In this episode of the Structure Talk podcast, the hosts welcome special guest Mike Casey, an experienced home inspector and educator. The conversation focuses on the topics of grounding and bonding in electrical systems. Mike explains that grounding connects the system to the Earth, maintaining a reference of 120 volts to the ground and providing a path for current to flow in the event of a lightning strike or other overvoltage occurrences. Bonding, on the other hand, connects metal components together that have the potential to be energized, ensuring that current has a path back to the source and preventing people from being in the path of a potential circuit. The hosts and Mike discuss the importance of proper bonding and grounding in various systems, such as pools, CSST, and detached buildings. They also address the changes in electrical code regarding bonding and grounding requirements. In this conversation, Reuben Saltzman and Mike Casey discuss the importance of bonding in electrical systems. They cover topics such as bonding gas piping, water distribution piping, and metal ductwork. They also touch on the bonding of metal siding and soffits. Mike emphasizes the need for proper bonding to ensure safety and prevent potential hazards. They also discuss the role of grounding electrode systems and the importance of understanding electrical theory. Mike recommends consulting an electrician or a knowledgeable home inspector for proper grounding and bonding inspections.
Takeaways
Grounding connects the electrical system to the Earth, maintaining a reference of 120 volts to the ground and providing a path for current in the event of overvoltage occurrences.
Bonding connects metal components together that have the potential to be energized, ensuring that current has a path back to the source and preventing people from being in the path of a potential circuit.
Proper bonding and grounding are essential for safety and preventing damage to electrical systems and appliances.
Changes in electrical code require separate paths for neutral current and equipment grounding and the use of four-conductor feeders for appliances with both 240V and 120V components.
Specialized grounding requirements exist for systems like CSST and pools, and it is important to follow the specific guidelines for each system to ensure safety and compliance. Proper bonding is essential in electrical systems to ensure safety and prevent potential hazards.
Gas piping, water distribution piping, and metal ductwork should be bonded to prevent potential energization and protect against electrical shocks.
Metal siding and soffits do not require bonding.
Understanding grounding electrode systems and electrical theory is crucial for proper bonding and grounding inspections.
Consulting an electrician or knowledgeable home inspector is recommended for proper grounding and bonding inspections.
Chapters
00:00 Introduction and Eclipse Experience
06:10 Grounding and Bonding: Definitions and Purposes
14:07 The Difference Between Grounding and Bonding
29:31 The Role of Electricians in Verifying Proper Bonding
39:02 Bonding Metal Ductwork
50:12 Understanding Grounding Electrode Systems
TRANSCRIPTION
The following is a transcription from an audio recording. Although the transcription is largely accurate, in some cases it may be slightly incomplete or contain minor inaccuracies due to inaudible passages or transcription errors.
Reuben Saltzman: Hey everyone, Reuben here. I’ve got a quick note for you about this podcast before sharing it. This is a lost episode, Tessa and I recorded this on April 11th this year and I lost it. But, it is now found again and I’m delighted to share it with you. Enjoy.
[music]
RS: Welcome to my house. Welcome to the Structure Talk podcast, a production of Structure Tech Home Inspections. My name is Reuben Saltzman. I’m your host alongside building science geek Tessa Murry. We help home inspectors up their game through education, and we help homeowners to be better stewards of their houses. We’ve been keeping it real on this podcast since 2019, and we are also the number one home inspection podcast in the world, according to my mom. Welcome back to the Structure Talk podcast. Tessa, as always, great to see you. Tessa, you just got back from watching the eclipse, didn’t you?
Tessa Murry: Me? Yeah. Good to see you too. I did, I took a road trip with family out to… Well, we didn’t know exactly where we were gonna view it. It depended on weather, cloud cover, traffic, all of that. But, we ended up in a small town south east of Indianapolis called Shelbyville in Indiana and saw the total eclipse for kind of the maximum amount of time. It was like four minutes and two seconds and it was unlike anything I’ve ever experienced. I am so glad that I was able to do that and travel and see it. And for anyone that has the opportunity to see a solar eclipse in totality, I would highly recommend it.
RS: Really? Okay.
TM: Yeah. Yeah.
RS: Now, I’m wishing I had gone.
TM: I don’t know. Yeah, it was fascinating just to be there for the whole process. And the temperature dropped, it got much cooler the more the sun was covered up by the moon. And then when it hit totality, it was dark out. We were at a park viewing this and all the lights went on in the park and it just took a look around and did a 360 view and it was like a 360 sunset. It was fascinating.
RS: Oh, cool.
TM: Yeah, and all the birds stopped chirping. It kinda got this weird… It was a weird color and it was just a weird feeling. And then the sun itself being blocked out by the moon was incredible, and it was beautiful, too. It was just really spectacular. So, fascinating, and, yeah. How was it in Minnesota?
RS: It was overcast and I wouldn’t have known anything was going on.
[laughter]
TM: Yeah, yeah, totally. Well, I don’t wanna take up any more time talking about this eclipse because we’ve got a special guest on today.
RS: We’ve got very special guest.
TM: Reuben, do you wanna introduce him?
RS: Yeah. Thank you. So today… And I think a lot of home inspectors, if they even heard the chuckling when we were describing it, you recognize that voice. We’ve got Mike Casey on the show today. Mike, welcome, sir.
TM: Mike Casey.
Mike Casey: Thanks to you both for having me, it’s a pleasure. We’re gonna have some fun here for an hour.
RS: Yeah, we are.
TM: Yes, we are.
RS: And for anybody who doesn’t know Mike, I feel like you’re the guy who needs no introduction but for anybody who doesn’t know him, Mike has been an educator, a voice in the home inspection world for much longer than I’ve even known about home inspections. How long you been doing this, Mike?
MC: This is my 38th year in home inspection.
RS: Wow!
TM: Whoa!
MC: I know, I can’t believe it myself. I can’t believe I’m that old. I actually had another profession before this.
TM: 1986? You’ve been inspecting since 1986? Wow.
MC: Yes. Mm-hmm.
RS: Holy cow.
TM: What did you do before that, Mike?
MC: I was a plumbing mechanical contractor in New England.
TM: Wow! Oh, my gosh. Okay.
MC: Yep.
RS: And Mike has got such a CV. I mean, I’d wanna list some of his accomplishments but that would take up the whole show. But, I mean, Mike, well, you’re a past ASHI President, right?
MC: Yes, 2002.
RS: Okay, 2002. And he has served on so many different boards. He’s run so many different education companies and…
MC: Yeah, several.
RS: Mike is just known as one of the best teachers, maybe the best in this industry. I mean, whatever conference I go to, you talk to people and if you got like five different classes being taught at the same time, you always try to pick which class you’re gonna go to. And you always run down, you kinda look at the speakers and it’s like, oh, Mike Casey is talking. Well, I don’t care what the topic is. It’s gonna be good.
MC: Well, thank you. You know what? Whatever the topic is, I do try to have fun. That’s for sure.
RS: You do and it shows, it shows. He’s always got such a smile and he laughs at his own jokes.
MC: Yeah. If I’m not having fun, I’ll fall asleep. I’m at that age now, so I have to have fun out there.
[laughter]
RS: I love it. Yeah. Mike, I want to be you when I grow up. There’s no doubt about it.
[laughter]
MC: Well, thank you. I appreciate that.
RS: Well, thank you so much for coming on the podcast, Mike.
MC: Sure.
RS: I thought, what do I want Mike to talk about? ‘Cause Mike could literally talk about any home inspection topic out there and I thought we’re gonna give him a tough one because we’ve had a number of electrical experts on here. We’re going electrical. We’ve had a number of electrical people on here, but Mike has got a gift of making stuff entertaining even if it’s a really boring topic. So, I thought about one of the most boring topics I could come up with for Mike and he’s still gonna make it fun.
MC: [chuckle] I know.
RS: So, we’re gonna talk about…
TM: I would add to that and say he makes it understandable and it’s…
RS: Yeah.
TM: The topic we’re talking about today, you might call it boring, Reuben, but I think for a lot of people in the home inspection industry, it’s one of the most confusing topics.
MC: Yes.
TM: And so, I think Mike is… I’m excited to hear kinda Mike dive into this today because I think he has a really great way of taking complicated things and making them easy to understand.
RS: Yes. Yes. Amen. Agreed. So Mike, today your challenge is to teach us all about bonding. And I don’t know how you can talk about bonding without getting into grounding…
MC: Grounding.
RS: A little bit. I mean, you gotta kinda distinguish the two. So Mike, please educate us.
MC: Alright. Well, I guess first of all, we should talk about grounding and bonding and they… Basically, they are two systems that overlap, however, they serve different purposes. So, they’re pretty similar. So, I think maybe we’ll talk about grounding first.
RS: Okay.
MC: So, grounding the ground basically is connecting your system to earth. And essentially what we’re doing is we’re maintaining the earth reference of 120 volts to ground. So, when you connect a neutral, when you connect a transformer to feed a house, you’re gonna have a neutral, the white insulated wire, and then you’re gonna have your two hots, usually a black and a red insulated. It doesn’t really matter the color insulation, but we create a neutral which is the grounded conductor and then that feeds into the house. Now, we wanna connect to the ground at the house too because we have this potential for millions of volts that could be in your system when there’s a lightning strike.
MC: So, lightning, where does it wanna go? Well, it wants to go to the earth. Its positive ions wanna party with the negative ions in the earth and it wants get there any way that it can. So, it’ll go through the systems in your house. If it doesn’t have access to the ground through a low resistance or impedance path, it’s gonna try to get through the systems in your house to get to the earth. And that’s your, telephone, your cable, your… Whatever systems you have in the house and this could actually ruin equipment in your home. So, we wanna limit this potential, we wanna give it a place to go. So, that’s why we earth the system. So, we’re maintaining potential to voltage. We have a location for where we have overvoltage occurrences which is lightning is one, could be a line surge and utilities have issues with… Something could go wrong or a transformer could blow up or who knows what could happen, but it could create a surge and we wanna limit that potential. So, grounding is basically connecting to the earth. And we’ll talk about equipment bond or grounding conductors a little bit later on ’cause that kinda interrelates with the bonding system.
MC: So, bonding is essentially connecting metal components together that have a potential to be energized. So, these are the components that aren’t part of the designed current-carrying system in the house. So, they’re not wires, they’re not conductors. These could be metal boxes, it could be ductwork that’s metal, it could be metal piping, not only for water piping but also for gas. And any of these components, if they become energized, we wanna make sure that we have a path for current to go. So, we wanna provide it a path back to the source, not to the earth, but back to the source of the electricity because without the current circle, I mean, you gotta have that path that two wires or to a path back to the transformer, current’s not gonna travel.
MC: So, if it doesn’t travel, it’s not gonna trip the overcurrent protection device or the fuse. So, if you don’t give it a place to go by bonding things together and then connecting to the equipment, grounding system, you’re not giving the current a place to go. So, what’s it gonna do? It’s gonna hang out, let’s say, in the gas pipe. Electricity is gonna hang out and it’s waiting for a path to get back to the transformer. And that could be you grabbing ahold to the gas piping and then maybe touching a water pipe at the same time and that water pipe is grounded, it’s a grounded surface ’cause it’s connected. So, it’s gonna try to go through you.
MC: So, basically, when we bond things together, we’re trying to keep people from ever being in what we call a series pass with electricity. You are always trying to keep people in parallel. And a person is a highly resistive path, we don’t work good as wires. We tend to burn up. [laughter] It doesn’t end well. So, if you have a wire, that’s gonna provide a good pass for that electricity and it’ll travel as fast and as much as possible, and it’s gonna trip to break. So, it clears the circuit and it provides it for safety. It turns off the electricity that’s basically leaking, which is what we call a ground fault. So, it’s a long explanation, I know, but it’s a complicated subject.
RS: So, basically, we’re making it so that if there is a leak, we make sure that it is a huge leak…
MC: Right.
RS: And it’s such a big leak that our safety devices, overcurrent protection devices, fuses, circuit breakers, whatever, it’s such a big leak that they recognize it.
MC: That it reacts, yeah.
RS: And then they shut stuff off.
MC: Right. Because not every circuit is protected by a GFCI that’s designed to protect people. That would be like kitchen, bathroom circuits where you have just a GFI that protects down to maybe six milliamps, which is a very little amount of current, but not everything in the house is protected by a GFI and it might not make a difference. So, basically, we’re trying to protect other metal components that are not part of the designed electrical systems. So, piping, ductwork, all these systems that could become energized. And a good example of that, I had it actually happen in a house that I was remodeling one time. We bought this house and I was fixing it up. After working all day, we were working on it at night, this is back when I was much younger.
MC: I was using a drywall screw, I think I was putting it into the wall for something and I’m putting this drywall screw in the wall and I hear in the other room. Oh, because I knew it was a breaker tripping. I’m like, what the heck? So, what happened was that screw just nicked a little bit of a BX cable which is a armored type of a cable and scraped a little bit of insulation off of the hot wire. So, it energized the screw as I was putting it in and the tip of the screw came to rest on a piece of copper water pipe and the water pipe was bonded. So, since the water pipe was bonded, that current that I now injected into that, or reduced, I should say, into the copper water piping was traveling as fast and as much as possible because there’s no resistor.
RS: Yeah.
MC: So, the breaker said, oh, hold it, that’s too much. So, the breaker immediately trips which prevents people from getting hurt where you would go in and maybe touch that or maybe the faucet in the kitchen you’d touch with one hand and touch the refrigerator with another hand. And if the refrigerator’s grounded, you could be in a path of a circuit. So, we wanna protect people from ever being in the path of any potential circuit. That’s the key thing that we’re doing with both equipment grounding and bonding. Now, the equipment ground is part of the branch circuit, but that doesn’t necessarily protect copper water pipe or galvanized water pipe or iron gas pipe because you normally wouldn’t be connecting anything to them, right?
RS: Yeah.
MC: There’s no electrical components there. So, that’s why we bond them to the system because they do have a potential to become energized. So, that’s the key thing is you gotta give the current a place to go. And the thing to remember is that electricity as soon as it leaves the transformer, it always is trying to return back to where it came from through any path possible. And it will try every path, not just the path of least resistance like you’ve heard with some electrical myths. It’ll take every path possible. Now, the amount of current that travels depends upon the resistance. The less resistance paths, the more current will travel but electricity will take all paths possible. So, that’s what we wanna do is reduce that potential for the path being a person because that’s never good.
RS: Yeah.
TM: So, just to clarify something, Mike. So, the electricity needs a way to get back to the main panel in your house and so that it can trip a circuit or blow a fuse, but ultimately it needs to get back to the main panel because then it goes back to the transformer where it came from. Correct?
MC: Absolutely correct.
TM: Okay.
MC: Yes, absolutely correct. Yeah, everything… Go ahead.
TM: I was just gonna ask, what about lightning then? Is lightning trying to get back to the earth? What is its source?
MC: Well, the source is basically the nature. Now, lightning wants to go to the dirt. Lightning is one thing, is voltage that wants to get to the dirt. It doesn’t care about the transformer, it’s not looking for that. The lightning wants to get to the dirt. That’s why it’ll hit… A lot of times, it hits trees because it’s a shorter path to the dirt because the tree has liquid in it and it’s a conductor and it’ll… Like golf courses, they tell you never stand under the tree in the middle of a golf course because that’s what’s gonna get hit. Now, lightning wants to go to the earth. That’s why we connect the house… One of the reasons we connect the house to earth is to provide a pass for that overcurrent.
TM: Okay.
MC: Or current spikes and lightning is one of those. You could potentially have millions of volts in your house, if there’s a direct lightning hit. It’s a lot of electricity and your house is definitely not designed to handle that. So, you wanna give it a place to go.
TM: Thanks for clarifying that, Mike, ’cause there’s multiple things going on in our electrical systems in our house, like we wanna connect all of these metal components that could carry current and we want them to feed back to the panel for overcurrent protection device and tripping of circuit breakers. We want that electricity to have a path back to the source where it came from.
MC: The source. Right.
TM: But, we also wanna protect our systems and our circuits and our appliances from overcurrent with like a lightning strike or a surge or something like that.
MC: Overvoltages, right.
TM: Yeah, overvoltage back to the earth and that’s why we’ve got things like grounding rods and all of that. So, all these different things are serving different purposes but they’re all really important.
MC: Yeah. Well, they do kinda overlap, bonding and grounding, but they do serve different purposes. A good example that I see quite often of improper bonding would be pools and pool equipment and bonding of your pool equipment. And the reason that we do it is because we wanna keep… And the reason we do it in your house as well is to keep everything at equal potential to ground. So, in other words, if one thing becomes energized, let’s say 40 volts, everything becomes energized at 40 volts. So, when you touch two different things, if it’s already energized, guess how much current’s gonna travel? So, it’s equal potential to ground.
TM: Mm-hmm, okay. Zero.
RS: Zero.
MC: So, if you touch something that’s energized at 40 volts over here and zero over here, what’s gonna happen? It’s gonna try to travel through you.
TM: Yeah.
MC: So, what we’re doing is keeping everything at zero potential to ground.
TM: Yeah.
MC: And I’ve seen pool equipment where they’ll connect the metal component like the pump, the filter and maybe another component that’s metal, connect them together and then run a wire, a piece of copper wire and then connect it to a piece of pipe or a rod stuck in the dirt. That provides you absolutely no protection…
TM: Okay. Yeah.
MC: Because electricity doesn’t like to travel through the dirt, it’s a highly resistive path. That connection needs to go all the way back to the panel.
RS: Sure.
TM: That makes a lot sense.
MC: Everything needs to…
TM: Yeah, you wanna trip it.
MC: You have to provide a pass for it.
TM: Okay.
MC: Yes. Now, typically with pools, if it’s a underground pool, you’re gonna connect your metal grid and everything all together and anything within four or five feet of the pool too because if you could reach it from the pool, you wanna make sure that it’s connected at equal potential to ground. So, just sticking something in the dirt isn’t gonna get you that path. You have to connect everything all together.
TM: That makes a lot of sense.
RS: Alright. Okay.
MC: I know. It’s complicated.
RS: Alright. Technical question.
MC: Yeah.
RS: And maybe I just can’t wrap my head around this. Why is it that up until 2008 in the electric code, it used to be allowed where you could have an outbuilding like a garage or something, a detached garage. If there’s no metallic pass between the two, you could have a subpanel and then you wouldn’t need to have a ground wire going from the subpanel back into the house. You could just have a ground rod for that subpanel. Why was that allowed?
MC: Okay, so just to clarify, maybe back up a little bit. You’re talking about a distribution panel, not a main panel.
RS: Yep.
MC: And installed on the same property and it’s a detached building.
RS: Yep.
MC: So, you would’ve a subpanel and years ago we were allowed to run a three-conductor feeder to that subpanel.
RS: Right.
MC: That’s what we’re talking about, right?
RS: Exactly.
TM: Mm-hmm.
MC: Okay. And what we would do at the subpanel is wire it like a main panel and they would connect grounds and neutrals together.
RS: Uh-huh.
MC: Right?
TM: Mm-hmm.
RS: Yep.
MC: And you would have a grounding electrode driven into the dirt, right?
RS: Right, yep.
TM: Mm-hmm.
MC: Okay. Well, that’s still required. Regardless. Any detached building requires its own grounding electrode mainly for lightning strikes and so on. But however, we now require a four-conductor feeder which separates the neutral current from the equipment grounding conductor which is the bare conductor and the white insulated conductor. Now, years ago, it was allowed because there was really… In that feeder that goes from the house to the separate building, there was really nothing connected that was potentially where you would be inducing neutral current into it. You see what I mean? In that that conductor didn’t connect to anything else, the feeder. But we still know it’s definitely better installation and much safer to keep the neutral and the equipment ground separate because you don’t wanna have the return neutral current traveling in parallel paths back to the source. You wanna keep those two separate.
RS: Got it.
MC: Now, years ago, I think you said ’08? I think… Yeah…
RS: Yeah.
MC: That’s probably about right where we were allowed the three-conductor feeder as long as there was no continuous metal path like you said, a fence or something, a water pipe, even. If there was a conductive water pipe like copper pipe between the two buildings, you weren’t allowed to do that. So, any type of conductive path between the buildings because there was a potential for inducing neutral current into the grounding system and that’s the reason for that. Okay?
RS: Ah, got it. Okay.
MC: So, any time there’s a… And that’s why now everything requires separation. So, as soon as you leave the main panel, there should never be a connection between neutrals and equipment grounds, ever, inside the house. So, we changed the rules for clothes dryers, kitchen ranges require the four-conductor branch circuit now. So, we’re trying to keep everything separate because we had lots of appliances that were connecting the equipment ground to the neutral and that neutral current was now traveling back in parallel paths. Now, it probably isn’t really gonna hurt anybody because there’s very little or no voltage behind it. However, as you know, the neutral carries current and if there’s a loose connection somewhere, what’s it gonna create?
MC: It still creates heat and it could cause a fire. So, that’s the reason why we wanna keep it on separate paths. It’s not a good idea to have those two overlap where you could send that return neutral current into your entire equipment grounding system. That equipment grounding system should not have any current travel at all ever unless there’s an emergency or a malfunction and it should only last a couple of cycles. So, maybe a tenth of a second until the breaker trips and turns off the power.
RS: And you know what, Mike? Maybe you can just clarify my thinking on this. My understanding of this has always been that on those older appliances, let’s say an old clothes dryer…
MC: Right.
RS: You didn’t… All it was was a 240-volt appliance. It was not a 120/240, it was only 240. So, everything that powered it was the two hot wires coming in and then that third wire was only a ground wire.
MC: Right. But then we started putting… Well, the problem was they changed the motor that turns the drum to 120, and the timer clock, the piece that you move, the time clock is 120 volts.
RS: Okay.
MC: Only the heating elements are 240 volts.
RS: Okay.
MC: And the same thing with the kitchen range is you’ve got 240 and 120-volt components inside. So, your heating elements are 240 but the time clock and the LED readout and the little buttons that you push, they’re all 120 volts. So, they require a neutral and they’re gonna send return current back on that neutral. So, you do not want it connected to the equipment ground. They need to be separate. We used to have clothes dryers, I remember hooking these up back in probably the ’70s where you would connect the cord to an electric clothes dryer. And inside under the cover, there was the two hot screws where you would connect the flexible cord and then there was another screw and it said on the little sticker, “Combination neutral ground,” which there’s no such thing. It just it was silly and I don’t know, we did it for a long time. That was just changed maybe 30 years ago.
TM: And which one would you connect…
RS: Yeah, I think it…
TM: To the neutral or the ground or both?
MC: Well, it was the same screw. It was one screw and it just said, “Combination ground neutral,” where you would just… And the cord only had three conductors in it, so you didn’t have a separate neutral like you really should.
TM: No.
MC: So, everything now is a four. If you look at modern receptacles for 240-volt appliances like arranged in a clothes dryer, it’s four slots instead of three slots because you have to have that equipment ground separate from the neutral.
RS: Got it. Okay. Thank you.
MC: Yeah. It’s a lot, I know, and it’s hard to understand. And a lot of this stuff, bonding and grounding and so on, there’s a lot of other systems that requires specialized grounding like yellow CSST and at gas feeders. I can’t tell you how many times I’ve seen where people make a mistake, they see that there’s a tracer wire sticking out of the dirt next to a riser from the city and somebody will say, “Whoa, that’s a bond and it needs to be connected.” Well, that’s incorrect. That’s a tracer wire because the pipe underground is plastic and that’s so that you can find it. So, that wire should never be connected to anything. It just hangs out there, just in case.
RS: Sure.
MC: Some states even have in their home inspector regulation, I know California is one of them, if we see yellow corrugated stainless steel tubing for fuel gas, we’re required to recommend an electrician verify the bonding.
TM: Wow.
MC: And that’s it. Yeah. It has to be an electrician which is a good thing because most plumbers don’t understand the bonding anyway or what it’s even for. They’re the guys that undo the telephone bonds and all this stuff underneath the house and you see ’em hanging all over. So, this is why we’re seeing a lot of inter-system bonding connections now where it’s all done at one place. And Reuben, I think you had just brought that up briefly earlier…
RS: Yeah.
MC: Where a lot of your main panels now have a wire that goes outside to that terminal log that’s designed for all the low-voltage systems like DirecTV or satellite TV or whatever it is and all these other systems to connect together with the house grounding and bonding system. So, everything’s all connected together. So, you have zero potential to ground and everything’s gotta pass for current flow to go where it needs to go. So, you either open the circuit breaker or if it’s from lightning, it goes to the dirt. It gets to where it wants to be and doesn’t try to go through your house to get there.
TM: Mm-hmm.
RS: Sure.
MC: So, it’s pretty complicated. Modern systems electrical are rather complicated.
RS: Now, let me ask you, Mike, for CSST, I mean, in California, so you guys got this rule where you gotta say have an electrician come out and verify it was properly installed.
MC: Other states too, so a couple other states too.
RS: Now, don’t you feel like most home inspectors ought to be qualified to figure that out themselves?
MC: Well, yes.
RS: I never thought it was that complicated.
MC: Yeah. Well, however, the state law and this was pushed by the manufacturers of the CSST like Omega and the other one. And they pushed it because they were having the issues with fire. So, they pushed… An electrician is the appropriate trade but they put the onus on the home inspector that if we see it, we have to recommend that an electrician verify a proper bond. So, they felt that the electrician was the proper license which I agree and that’s fine with me. If they don’t want us to do it, okay. I’ll just recommend an electrician.
RS: Okay.
MC: So, I got no problem complying with the law.
RS: Now if it is properly bonded, if you’re gonna bond your CSST, your yellow CSST, what would that look like?
MC: Well, the proper way to do it is as soon as the hard pipe enters the house, it should be bonded usually within about five feet of where it enters the house. And you wanna connect the bond wire, and usually it should be about a number of six copper. So, that’s a pretty fat wire. That’s like pinky size wire, it’s a pretty big one. And that should be connected to the hard pipe, the iron pipe before it changes to CSST within about five feet of where it enters the house and it should be done with a proper clamp, a bonding clamp that clamps, not a stainless steel hose clamp but a proper electrical clamp. Well, I’ve seen it, so it should be a proper clamp for bonding and it needs to be connected where there’s no paint and so on and then it should connect back to the neutral terminal bar in the main panel or you can’t connect it. What’s that?
RS: Could it go anywhere else on the system? Could it go… Let’s say you’ve got copper water tubing coming up from the ground, could you bond to that instead?
MC: I don’t think so. I think you have to either go back to the neutral terminal bar in the main panel or you could splice it to the grounding electrode conductor.
RS: Okay.
MC: You could connect air with like an acorn clamp maybe or something or a split bolt…
RS: Okay.
MC: Would be a way to do it, but that’s about it.
RS: Okay. Got it.
MC: As far as I know, that’s it. So, you don’t wanna be… ‘Cause here’s the problem with water piping, it’s not reliable. Piping gets changed.
RS: Well, let’s say it’s the piping coming up from the ground that stubs up and then you’ve got another bonding clamp for your whole system right there bonding the water piping.
MC: Well, in theory, I agree with you. Yes, it would work. However, there’s a likelihood that piping would be changed to plastic some day.
RS: Okay.
MC: So, I wouldn’t consider it to be reliable. If you connect to the grounding electrode conductor or the neutral terminal bar in the main panel, you could pretty much rely on it not being molested if there’s a changeout in the plumbing.
RS: Okay.
MC: ‘Cause at some point that copper pipe’s gonna get replaced, most likely.
RS: Sure.
MC: It could be 50 years from now, but at some point it’ll get replaced.
RS: Okay.
MC: So, it wouldn’t be considered to be permanent. Really the main thing you wanna do is protect that copper pipe with a bond in case it ever became energized. And that’s separate, that’s a different piping system than the fuel gas.
RS: Okay. Got it.
TM: Mike, you bring up a good…
MC: Yeah, that number…
TM: Yeah.
MC: I’m sorry, that number 60 is to go, the best way is, all the way back to the main panel.
RS: Okay.
TM: Well, you bring up a good point, Mike. Yeah, I was just gonna say, if someone’s remodeling their house and they’ve got a bunch of either galvanized steel, water distribution piping or copper or whatever and they replace a section of that and maybe it’s disrupting that potential flow of current, now they’ve potentially created some really unsafe conditions in their house that they’ve messed up that connection. Right?
MC: Well, yeah, we see that all the time in basements and crawl spaces where we can get to the piping and I’ve seen it where the galvanized piping has been abandoned. It’s still in place because it costs money to get rid of it.
TM: Yeah.
MC: It’s labor to take it out, so a lot of times it gets left in place but it’s no longer used and it’s disconnected. So, it’s just kind of a system that’s hanging there. Now, it still has a potential to become energized, I think.
TM: Yeah.
MC: And something could touch it and energize it…
TM: Yeah. Yeah.
MC: But, sometimes it won’t be bonded. It’ll be just left there. Sometimes, the bond is still connected to it but there’s not a new one to the copper pipe that’s installed in the house. So, my feeling is both pipes systems should be bonded. Even though one is abandoned, it’s still there and it still can become energized and it still could hurt someone. So, the old and the new system should be bond. If you wanna get away from the bonding requirement, you could just remove the old galvanized… That’s the way to get around it, but I think… I don’t care if it’s being used or not, it’s still a metal piping system that has a potential to become energized and hurt someone. So, some people may disagree with me, but usually it’s just disconnected from the supply, but it’s all still hanging there and the same hazard exists.
RS: Yeah.
MC: It still could become energized and if it doesn’t have a place for that current to go, somebody could get hurt when they grab ahold of it.
RS: That makes sense. Sure.
TM: Unless you have a really good home inspector who understands grounding and bonding and you have all of this, the plumbing and ductwork and all these metal components exposed, like there’s a good chance that a house has an issue with this bonding or grounding system or both. And so…
MC: All the time.
TM: What should a homeowner do if they’re concerned about this? I mean, who should they contact? What should they do?
MC: Well, I guess, the appropriate trade is an electrician to check your house for proper grounding and bonding. So, an electrician would be the properly licensed person to do this. Now, an appropriately educated home inspector, if you’re purchasing a house or maybe you’ve already purchased it and you would like to have things spot-checked, a home inspector should be able to determine if there’s a pattern of issues with the electrical system and would most likely be recommending an electrician who would then do a more in-depth study of the grounding and the bonding system and, of course, the line supply system as well. So…
TM: Yeah.
MC: Electrician’s the appropriate person, but a home inspector should understand equipment grounding, earthing of the house and also bonding of the metal components. It’s very important; it’s a safety issue and it’s something that inspectors should learn, should know about.
RS: Yeah. Alright, we talked about gas piping. I got another one for you, Mike, if you can just explain this one. We used to see gas piping would be bonded to the water piping, you’d have a couple of big clamps and you have a thick copper wire going from the gas piping to the water piping back when we had stuff like gravity furnaces, but now most of those gravity furnaces are gone and they’ve switched over to forced air and we don’t have that big thick copper wire going there anymore. Please explain what we’re doing to bond our gas piping now.
MC: Okay. Well, gravity furnaces typically did not have 120-volt circuit going to. They used what’s called a milliamp system to open up the gas valve. So, it was fueled… Actually, it made a little bit of electricity milliamp with a flame. So, you didn’t have a line voltage system to it. Modern systems now what we see are forced air. They use 120-volt branch circuits to operate the fan and so on. So, you are allowed to bond hard pipe fuel gas pipe, so non-CSST. So, the non-flexible stuff, basically. So, hard pipe that’s threaded, iron, you are allowed to bond that by its connection to a gas valve that’s inside the furnace as long as that system has an equipment grounding conductor. So, it’s bonded by virtue of its connection to the metal gas valve and to that system, that furnace that has the 120-volt usually branch circuit to it with a hot, a neutral and an equipment grounding conductor ’cause remember, everything inside the furnace is bonded together. It’s all connected together in case something becomes energized.
MC: And so if that gas pipe became energized, the current from it would travel from the equipment grounding conductor in the gas furnace back to the main panel and it would go up to the transformer or down or wherever it has to go to the transformer and that would trip the circuit. And even sometimes it doesn’t trip the circuit because it’s such a small amount of current. It might just be a 2-amp leak, which is a ground fault is basically leaking current, kinda like water leaking out of a pipe. With this case, it’s electricity. So, it’s such a minor leak, it’s not enough to trip the overcurrent device. However, if you’ve got a bond wire or an equipment grounding wire connected, that’s the path back to the transformer for the current. So, you’re still keeping people in parallel with a potential circuit, not in series and if you touch it, it’s not gonna like you ’cause you’re a much higher resistant path than that wire that’s connected to that gas furnace.
RS: Okay. Got it.
MC: So, it’s a much more desirable path. Remember, more current will flow through the path with the lowest impedance, which is resistance. So, you’re gonna have a lot of resistance. That’s why when people are being electrocuted, they tend to burn and so on. That’s because we’re not very good conductors, so we heat up and it doesn’t end well.
RS: Yeah, yeah. Alright. So, we’re thinking about furnaces and that makes me think about the metal ductwork for your furnace. Does that have to be bonded?
MC: Well, it’s bonded by virtue of its connection to the furnace, typically, to the box, to the metal plenum and so on. However, on systems with metal ductwork, let’s say in commercial buildings where… Residential almost everything is flexed up, so you don’t really have any potential there for it to become energized except maybe the little tiny wire that’s the reinforcement through the plastic, which that’s not gonna carry a whole lot of current. But if you have metal ductwork, oftentimes we have to bond across that, especially across the vibration dampers…
RS: Yep.
MC: Which are kinda like a neoprene sort of a boot between ductwork to try…
RS: We got ’em in basically every house in Minnesota.
MC: Yeah. There should be a bond across that. Usually, it’s a little jumper, a little piece of copper wire or something because if you have a vibration damper and it separates electrically, the metal box, the enclosure that’s bonded because that’s where the electrical connection is, right?
RS: Yep.
MC: That’s where the equipment ground is. Now, the rest of the ductwork, the other side of that vibration damper is not gonna be protected at all. So, it could become energized and that current could just be hanging out there waiting for you to touch it. So…
RS: See, that’s interesting.
MC: I would recommend it be a jumper to cross.
RS: I have never seen such a device.
MC: Really?
RS: I mean, thousands and thousands of inspections I’ve done in Minnesota, never seen such a device. I don’t even know what it would look like. I’d know it if I saw it, I’m sure.
MC: Yeah. It’s just a little strap.
RS: Interesting. I wonder why we dont.
MC: So, you have metal ductwork throughout the house?
RS: Yeah. I mean, the return ductwork is always metal. The supply trunk is always metal and then maybe, who knows? Depending on the age of the house, older houses, you’re gonna have metal ductwork going all over the place and I bring this up because I had an inspector on my team who was… He was barefoot at the time or maybe had damp socks on and he was standing on a concrete floor. He reached up and he touched the metal ductwork and it was fully energized and he got lit up. It’s one of the few people I’ve ever sent to the emergency room on my team…
MC: Wow.
RS: ‘Cause he was having like weird heartbeats after that, and it wasn’t bonded.
MC: Yeah. Because remember, the concrete slab is actually a grounded surface if it has steel in it.
RS: Oh, yeah.
MC: Yeah, it could… It’s not gonna… You have a potential for current flow through you. Well, there’s the reason why the ductwork should be bonded.
TM: Yes.
MC: I don’t know why they’re not doing it. I know when I was a mechanical and plumbing contractor in New England, it was a requirement and when I see it mostly here in California where I inspect, the only time I see metal ductwork is in commercial and it’s pretty much required. So, if I don’t see the bond, the strap, I recommend it. And a lot of times it’s there but it’s laying to the side, it’s not connected on both sides. Somebody unscrewed it and just left it. They were doing some work and didn’t put it back. Kinda like what we see in basements and crawl spaces all the time with the telephone system bond, with the satellite TV bond, they’re hanging in the air. Air is not a good bond, it has to actually connect to…
[laughter]
RS: I think Rayback [0:44:06.3] ____ is gonna like you.
MC: Well, electricity can travel through the air because it’ll burn the oxygen. That’s a plasma flame, that’s really hot. So, you definitely don’t want that to happen in your house. That’s arc fault. So, we don’t want that to occur but…
TM: Plasma flame is an arc fault. That’s a new terminology.
RS: Arc flash, right?
MC: Arc flash, I’m sorry. Yeah. Arc flash, you’re right. So yeah, you don’t want that occurring in your house especially with you close to it.
TM: No.
MC: It probably can happen.
TM: No, not all.
MC: So yeah, ductwork should definitely be bonded because it has a potential to become energized and if there’s no pass back to the source, there’s no way to open the circuit with the circuit breaker.
RS: Well, I’m not gonna start tilting at windmills here in Minnesota and trying to change that, but I might ask somebody locally why we don’t do that. That is interesting.
TM: Or maybe why it’s not enforced.
MC: Yeah. Maybe check with your local… Your electrical inspector or combination inspector. Just give ’em a call and see what’s up.
RS: Yeah. That’s a good question, ’cause we adopt the national electrical code in whole. We don’t make any amendments to it.
MC: Well, any metal system then is required to be bonded, so that usually includes ductwork.
RS: Alright, I got one more I got to ask you about.
MC: Sure.
RS: What about water distribution piping? It’s bonded where it comes in at the house, you got a water meter that breaks the bond but then we always have a jumper going over the water meter…
MC: Never say always.
[laughter]
RS: Well, I was supposed to. Yeah, I’ve seen it missing many, many times but it’s supposed to be there. And then the piping goes into the water heater, it comes back out of the water heater. What is maintaining the bond between the water piping going in and coming out?
MC: Steel tank.
RS: Okay, alright.
MC: Yeah. Now, we used to put in jumpers because it came with the water heater but I think… This is years ago. When you purchased a water heater, it would come with a couple of clamps and a piece of wire, so did washing machines where you could connect the green wire from the washing machine to the metal water pipe or something. They don’t come with those anymore. We figured out we don’t need it. But with a water heater, it’s a steel tank.
RS: Alright.
MC: Now, some jurisdictions still require a jumper. I think they’re probably in New England somewhere that require that because it’s just… You don’t need it. You got a steel tank and that’s gonna maintain the continuity in your equipment grounding system or your bonding system.
RS: Okay. So, every time I replace the water heater, I like to install dielectric unions to make it easy for me to replace that water heater next time. I’m breaking that bond now, right?
MC: Well, you just broke it. You just broke it, yeah.
RS: I just broke it.
MC: Yeah.
RS: So technically, there should be a jumper going across those, right?
MC: Yeah, above the dielectrics.
RS: Yeah. I’ve never seen that done.
MC: Never?
RS: Tessa, have you ever seen that done?
MC: No, I’d recommend it. When I see dielectrics, I recommend that it be done. But typically, your hot water piping connects somewhere else. It’s gonna bond somewhere.
RS: Like the shower valve?
MC: Yeah. You’re connected to different valves that are gonna be brass through your faucets. But the problem is with faucets is usually your supplies are plastic. So, shower valve or a tub valve would be another connection but we don’t know what’s in the wall. So, that’s unreliable. So yeah, if you see dielectrics, which I don’t see those very often.
RS: Okay.
MC: So, I would recommend just a jumper across. And I’m sure nobody does it, but I’d recommend it.
RS: No, no.
MC: And there’s a little picture of it that you can put up, so.
RS: Yeah, I’ve seen it in code check before.
MC: Yes.
RS: I think they’ve got a picture of it.
MC: Yep. Yeah, you can do that. So, it just depends but I just wanna see some kinda connection to the cold water piping. Now, you also, if you’ve got metal piping coming in from the street or from the well, that has to be connected to the equipment or the…
TM: Grounding electrode?
MC: Grounding electrode system. Gosh, I have to think about my topics here. The grounding electrode system because you have to connect to all available electrodes. So, anything that’s metal that’s in the dirt that goes to the house has to also be connected to that system. So, you might be looking at that too.
RS: Sure.
MC: That works. That’s all interconnected with… That does go to the neutral terminal bar in the main panel. So, that provides you with a path for current too.
TM: Well, Mike, can you say just in practical terms like what a grounding electrode system looks like, what it is? What’s an example of that?
MC: Well, typically, what we see are the most common in new construction, let’s say in the past 20 years, the grounding electrode for the house is the concrete-encased steel. So, it’s the rebar that’s in the foundation, minimum 20ft long. And you see a clamp connects to that and they stick it up out of the foundation stem wall, usually close to the main panel somewhere. And there’s a blank cover that goes over that box. It’s a 4X4 box usually or 6X6. And inside that is the clamp, that’s our grounding electrode. Some homes will require a driven rod. You see when it’s a replacement, like a heavy up of the service. Many houses require two of ’em to get the proper resistance. To get below the number that you need, you have to put in two of ’em.
MC: And there’s other ways to do it. You can use a grounding ring around the house and all kinds of other complicated methods. But the most common that we see is gonna be the rod or a concrete-encased electrode. And then from that, there’s a wire that’s clamped to it and then that wire goes to the neutral terminal bar in the main panel. And that’s pretty much it.
RS: Cool.
MC: Yeah, not much to it. Although if you break it, if you disconnect it, then if lightning hits the house, you have a problem because it can’t get to the dirt. If you have an overvoltage condition, maybe a line surge or something like that, it’s got no place to go. So, you really need that to maintain that 120 volts to ground reference that you created at the transformer by creating the grounded conductor which is the neutral.
TM: Okay.
MC: I know it’s a lot. Electricity is complicated but it’s fascinating.
TM: But it’s life or death too, so it’s an important thing to understand.
MC: It can be.
TM: So, going back to the bonding different things, we talked about metal water piping and metal ductwork and gas piping, I’m curious about, what about metal siding on a house, Mike? Are you supposed to bond that or metal soffits? And how do you do that?
MC: It’s not required.
TM: Really?
MC: It’s not required to be bonded.
TM: Okay.
RS: Okay. Good, ’cause I’ve never seen that either.
TM: Haven’t neither.
MC: No, it’s not required. Now, it used to… 50 years ago, I used to see it where they try to bond it and drive a metal rod into the ground next to it which isn’t gonna do any good. And it’s probably bonded by virtue of it touching boxes and so on anyway, but it’s not required to have its own separate system for bonding or grounding. Good question. I’ve heard that.
TM: Yeah, thanks for clarifying that ’cause I have seen in a few situations where you’ve got an overhead service coming to a house and those lines go behind the siding, they’ve sided over it and with metal siding…
MC: Okay. Well, that’s a different… Yeah, it’s probably not supposed to do that. So, if they… That’s a job where they came in to put the siding in and was the low bidder who didn’t have an electrician pull that off the wall, so they could put the new siding and then reattach it correctly. So typically, the service drop should not go behind the siding and even the SE cable that would go from the weatherhead down to the main panel, that should be surface mount. You should not see it going bulge behind the siding. That would not be correct path.
TM: Okay. Thanks for clarifying that.
RS: Got it.
MC: Sure.
RS: Well, Mike, this has been fantastic.
MC: Oh, we’re done? Wow.
[laughter]
RS: We’ve got an hour we just talked about bonding. It goes by fast, doesn’t it?
TM: Yeah, well…
MC: It sure did. I know. It’s a complicated subject.
TM: I was gonna say, I don’t think our brains can take anymore, Mike. So, thank you.
RS: Yeah, I don’t… We’d have to do a part two if we talked anymore ’cause…
MC: Sure. I know. I need to take a nap now.
[laughter]
RS: Small bites of this. This is a big bite.
TM: Yeah.
MC: Yeah. This was a big one, that’s for sure. It’s a lot to understand. And you know what? It takes some time and study and really, once you just believe electrical theory, if you go to a class about electrical theory and how it works and if you just believe…
[laughter]
MC: It makes… It’s hard because you can’t see it, but if you just believe, then it all makes sense.
RS: Yeah.
MC: If you just believe how it works, you’re like, “Oh, I got it,” basically, the light bulb goes off and you’ll understand and it’s much easier to inspect because you understand how things work and what they’re for.
RS: Yeah.
TM: Yeah.
MC: So, that’s my recommendation.
RS: Well, Mike, let me give you a plug. Where are you speaking next? You got a speaking engagement coming up soon?
MC: Gosh.
TM: Which one? [laughter]
MC: Which one? And I know I’d have to… I know in the fall we’re doing Inspection Fuel in Dallas. I think I’ve got something. Let me take a look here.
TM: You teach all over the country, don’t you, Mike? You teach at a lot of different ASHI chapters?
MC: Yeah, usually the summer is slow. Yeah, all over. I just got back from Ohio and Arkansas and Florida.
TM: Wow.
MC: So, the summer kinda slows down a little bit. So, yeah, probably in the fall like Inspection Fuel in Dallas. That’s the next big one that I’m speaking at. So, just all over the place.
RS: Anything else you wanna plug, Mike?
MC: Gosh, I can’t think of any. I’ll probably remember it as soon as we hang up.
RS: Well, if you do, you send me an email and I’ll put it in our show notes. I’ll give you a link where people can find you.
MC: Oh, okay. Great.
RS: You got a website to throw out there?
MC: Michaelcasey.com. Easy.
RS: Perfect.
TM: Nice.
RS: Excellent. Alright.
MC: Alright.
TM: That was no pun intended when you asked if he had a plug, right?
[laughter]
MC: Oh yeah, that’s a good one.
RS: That’s not intended, Tess.
[music]
MC: The proper term is receptacle.
TM: Oh, yeah.
[laughter]
[music]
TM: Very good.
RS: Love it. Well, Mike, can’t thank you enough for all your time. Appreciate it, sir.
MC: It was fabulous.
TM: Thanks, Mike.
RS: Always good to see you.
MC: Alright.
RS: Alright.
MC: See you. Take care. Thank you very much.
TM: Take care.
MC: Bye.