100 Days of the 2026 NEC Changes Day 77: 555.14 Equipotential Plane

Added: 2026-05-12

[00:00:01][music] [music] Hey everybody, Ryan Jackson once again.

[00:00:18]Hope you're doing well. We're still talking about article 555, Marinas, Boatyards, floating buildings, docking facilities. Let's take a look at section 14. So 555.14 equipotential plane the equipotential plane requirement was expanded and clarified kind of and the construction of the plane is now addressed and also uh we made a similar change to article 547 which is agricultural buildings and 682 which is for natural and artificially made bodies of water. Now, when I say a similar change, I mean we're actually telling people how to create the equipotential plane, whether it needs to be rebar or 8 gauge wire or what have you. All right? So, not so much when you need to have it, but what it's made out of. That was changed in 547 and 682 as well. Okay? So, 555.14 equal potential plane. An equal potential plane must be provided near all outdoor service equipment and disconnecting means for equipment in or on the water if the voltage exceeds 250 volts to ground and the equipment is within 10 ft of the water. Okay. So looking at this picture here, I do not need to do any sort of equipotential bonding for this because this does not exceed 250 volts to ground. Right?

[00:01:35]Remember 277480 is what we're talking about here. So, if you don't have 277480, then don't even read this section. But if you do, then you're going to have to have equal potential bonding. If you have 277480 and the equipment is within 10 ft of the water.

[00:01:51]Now, I'm going to tell you what the code says and then I'm going to tell you what the code was supposed to say. And when I say what it was supposed to say, um I brought this up this issue up.

[00:02:01]Unfortunately, I didn't catch this problem in time to fix it. Um, I usually because I read all the proposals and every comment, you know, I I'm I'm a nerd, you know me. And a lot of times I'll I'll be able to to fix things before they before they get printed. Uh, I didn't catch this and I brought it to the attention of panel 7 and they told me what this was supposed to say. Um, this rule is not intended to apply to equipment on the dock. Okay? It's intended to apply to equipment on land, not on the dock. All right? So, just try to remember that. And hey, if you're a person, if you're a literalist and you say, "Hey, I don't care what it's supposed to say, Ryan. I care what it does say." I I get it. I mean, I I understand, but I think that might be a close-minded approach. So, hopefully, you know, the intent is is pretty important.

[00:02:50]The equipment must be bonded to the plane and to any metal enclosures likely to become energized with an eight gauge or larger conductor, and the plane must comply with one through four. All right.

[00:03:02]So here we have some disconnecting means for equipment in or on the water and it's 277480.

[00:03:11]So I need to have an equal potential plane. So I'm basically going to be standing on the same voltage as the enclosure itself. Right? And that's the whole idea here. Remember if you uh if you take your meter and you touch both test leads to one object, the voltage is zero. Right? Even if the voltage to ground is 100 or 100,000, if you touch both your test leads to one point, the voltage is zero. So if I bond them together, the voltage from here to there is also zero. And that's my whole objective here. So I want my feet at the same voltage as my hands because I'm trying to reduce step potential and touch potential. All right. So the equipotential plane needs to be 8 gauge or larger or excuse me needs to be connected to the equipotential plane with 8 gauge or larger. The plane is going to be constructed as indicated in 1 through four. And all of this material is new.

[00:04:06]Number one, you can use rebar. If you want to use rebar in the pavement, in the concrete, great. Do it. That's your potential plane. And the rebar can be tied together by the regular old tie wires or similar. So you don't have to weld it or, you know, acorn clamp every piece of rebar or anything. Just just tie it together, put it in the concrete, pour the concrete, right? Connect the eight gauge wire to it, you're good.

[00:04:29]You can also use a copper grid if it's 8 gauge or larger solid copper bonded in accordance with 250.8, which would mean exothermic welding or listed clamps, right? It's probably going to be exothermic welding. Uh, and it has a maximum grid spacing of 12 by 12 with a 4 inch tolerance. So, 8 to 16 inch spacing and uses listed splicing devices or exothermic welding. All right. So, you can buy uh a roll of this, right, that you can use to bond your uh swimming pool perimeter surfaces. So, you can buy it in a three-foot roll. Get some of that, put it underneath the equipment. There's your equipotential plane. Run an eight gauge wire to it.

[00:05:13]Connect the eight gauge with a listed device or exothermic welding and you're good.

[00:05:21]You can also use steel welded wire. And steel welded wire would just be the, you know, the stuff that you normally see in a concrete slab because we're not trying to trip breakers here, folks. All we're trying to do is connect this to that. So it doesn't have to be some massive piece of four out wire here. Just regular old steel welded wire can be used as long as it's fully embedded in the surface material and bonded using uh steel tie wires or similar. So like this, it's all you got to do if the surface material does not contain steel. So here we're looking at non-conductive surfaces. If the surface material does not contain steel or if the steel is encapsulated in a non-conductive compound then a copper grid must be placed under the surface no deeper than 6 in below grade. This is uh a scenario where you would have to do that if this was within 10 ft of the water. Okay. So 480 volt non-conductive surface right grass. So, we're going to have to put a uh a bonding grid underneath it, underneath the grass, right? Not more than 6 in below grade. We've been doing that for a long time with uh with swimming pool decks. The the problem here is they basically they copied the rules from the swimming pool articles and pasted it here. And it makes sense for swimming pools. And it makes sense in this application when we're talking about equipment on land.

[00:06:55]But what if I have a non-conductive deck, right, that's over the water and it's wood like they usually are and I've got equipment out there. How would I have to put 8 gauge copper underneath the wood? That's not going to do anything. So, you know, I I'm going to ask you, you know, sometimes try not to be a literalist. Sometimes, you know, the code's written by humans and we're all fallible. We all screw up. God knows nobody screws up more than I do, right?

[00:07:24]So when you read a code rule and and the the end result is something that is totally absurd, then maybe you need to look back and and reach out, ask people that were invol involved in the process or ask, you know, ask for some other people's opinion because it would make no sense whatsoever to put a an equipotential grid under the wood deck, right, of the pier and and not have it do anything. So this was intended to apply to equipment on the land. And if you can remember it from that lens then I think uh you know understanding the intent makes a lot more sense.

[00:08:01]Utilization equipment on the dock or floating building is not required to be connected to the equal potential plane.

[00:08:06]Again the utilization equipment does not have to be. It's the disconnecting means for the utilization equipment that has to be all right. So don't worry about the utilization equipment. It's just the disconnect. All right. Uh something strange in that picture by the way. Let me know if you see it in the uh comment section. All right, there you go. Uh 555.14.

[00:08:28]Not a perfect section, but none of us are perfect, you know, and we'll fix it in the 2029, right? We'll we'll make it say what what it was supposed to say. In the meantime, I think, you know, use your brain, right? Don't just, you know, mindlessly read the words in the book and uh and assume that they're perfect because that's never going to be the case. All right, hope you enjoyed the video. We'll uh see you next time. And we've got another video in article 555 yet to come. I mean, look, it's a it's a big subject, so there's going to be a lot to talk about. Next time, we're going to talk about receptacles in 555.33.

[00:09:00]I'll see you then. Please continue to work safely and uh take care.