Seal electrical boxes with aluminum tape?

[TomR]

I just had some new 100-amp electric service panels put in by a licensed electrician. One is a new house panel in the basement where the old panels were located, and the other two are in the upstairs apartments (one in each apartment). The new house panel is in the basement where there used to be two old panel boxes. The individual circuit wiring for each of the two new upstairs apartment panels drops down to where the two original panels were located and each circuit is tied in there. That leaves all of the house wiring as it was before, but connects the old circuits to the new panels.

Rather than use the original old panel boxes as junction boxes, the electrician created new smaller junction boxes there by starting with a regular metal 4-inch junction box and then stacking one or two 4-inch metal box extenders on top of that to create a larger junction box. And then, of course, there is a metal cover plate.

To be clear, here are 3 photo links showing the basic junction box type that I mean, plus the metal box extender, and the metal cover plate:

When I look at the newly-created junction boxes, it looks to me like they don't quite fit together too well and there are some visible gaps (maybe

1/16 to 1/8 inch max) between the stacked boxes. I am wondering if that may be considered a problem since theoretically there could be sparks inside the junction box sometime in the future and maybe the box wouldn't fully prevent the sparks from exiting the box.

I, of course, do have a permit and I am about to call for the final inspection. I will be there for the final inspection that will be done by the electrical subcode official.

Here's my question:

If by chance the inspector says the gaps are not acceptable, would it be possible and acceptable to solve that problem by just wrapping the boxes with several layers of metal aluminum tape -- maybe even high temperature aluminum tape? My plan would be to have the metal tape there with me just in case, and if it is okay with the inspector, just wrap the boxes quickly while he is still there so he won't have to come back and re-inspect.

I know it is up to the inspector, but I am just wondering if anyone has ever done this, or if sealing metal junction boxes with metal aluminum tape is ever done and considered acceptable.

[DerbyDad03]

I've never heard of using any type of tape to "seal" a junction box to keep sparks in. Seems to me that just what is sold is what is always used.

However, your description has me wondering about something else:

You said "...starting with a regular metal 4-inch junction box and then stacking one or two 4-inch metal box extenders on top of that to create a larger junction box."

I wonder how many of these extenders you are allowed to use before a panel is actuallly required. It seems to me that three 4" boxes (that's a foot!) sticking off of a wall would be an issue in and of itself.

I'd like to see a picture of that setup.

[clare]

plate:

I believe he is talking about 4 inch X 4 inch boxes that are about 2 inches deep - so mabee 6 inches thick off the wall - or was it standard gang-boxes? so 6 to 8 inches wide across the wall. That would make more sense to me.

[Ralph Mowery]

The boxes are 4 inches square and only 1 1/2 to 2 inches deep. It would only be 6 inches at the most.

[RBM]

plate:

They're 1 1/2" deep X 3 = 4 1/2" deep. Still a crappy job in my opinion

[TomR]

I may not have described it very well. I meant that the boxes are 4 inches across (as shown in the phot links), not 4 inches deep. So, each box is 4 inches across and 2-1/8 inches deep. Two boxes stacked would be 4-1/4 inches deep. Three boxes stacked would be 6-3/8 inches deep.

I never saw this setup done before to create a junction box, but that's what I have now. It does take up way less space than the old original panel boxes would have taken up. And, it does look better, except for the possible glitch of what looks like small gaps between the boxes.

Sorry, my camera is missing and it has been missing for about 3 weeks, I keep thinking it will turn up someplace, but so far no luck.

[RBM]

The extension boxes never fit tightly together so I doubt the inspector will have an issue with that. If the electrician needs to stack that many boxes together to achieve proper box fill, he should be using a different box or a small trough. Doing what he did will make it really difficult to access any of the splices made in the first box, not to mention being an eye sore. If there is no other violation found, IMO doing this doesn't meet Nec 110.12 " electrical equipment shall be installed in a neat and workmanlike manner"

[TomR]

Oops, I wrote that they are 2 1/8 inches deep, but I think you are right and they are 1 1/2 inches deep. I'll have to look again and double check to be sure.

And, yes, it did strike me as an odd (a.k.a. crappy) setup. I would have expected that he could have put in whatever size junction box that was needed as a single box rather than cobbling together 2 or 3 of these on top of each other.

But, that's what I got and now I have to wonder if the inspector will gig me on that or just let it go as is. Even if I don't get gigged on it, I think that I would like to wrap the boxes in high-temp aluminum tape anyway after the inspector leaves -- assuming that isn't a problem for some reason.

[TomR]

Thanks. That's good to know. Hopefully, I won't get gigged on that and I can move on from there.

[John Grabowski]

*He could have used a 4 11/16" square x 2 1/8" deep box for several circuits. Having multiple extensions doesn't make sense. Of course 4" boxes are cheaper than anything bigger. Maybe a low bid job. I hope the conductors are long enough to extend out of the box.

[willshak]

I am not an electrician, but I am wondering. If something required you to get to the first box in that stack, wouldn't you have to remove the second and third boxes to get to the first box, or am I missing the point?

[Ralph Mowery]

The boxes are not full boxes. The first box will have a bottom and 4 sides and provision for a cover. The second and other boxes if used will only have 4 sides and provision for a cover. It will not have a bottom. As you stack them, the upper boxes just make the first box deeper so to speak.

[Roy]

Do NOT wrap those boxes with ANYTHING. They must be left AS THEY ARE. They must be accessible at all times. There should be NO sparks inside those boxes EVER. Where did you get that idea of sparks?

[RBM]

must be accessible at all times. There should be NO sparks inside those boxes EVER. Where did you get that idea of sparks?

If a connection shorts out, or comes loose within the box, there WILL be sparks

[RBM]

Even so, as John Grabowski said, the Nec requires any spliced conductors to be long enough to stick out of the box 3 inches.

[Harry K]

The inspector will "gig" the job, not you and your electrician will have to fix it on his dime.

Harry K

[Harry K]

Except there is a "lip" around that open bottom on the inside. Very NOT fun to work in them.

My bet is the inspector will have an attack of the horrors when he sees that cobbled up job.

Harry K

[TomR]

True, but if he does gig the job, and a simple fix that can be done on the spot is acceptable to the inspector (such as sealing the gaps by wrapping the box with high-temp metal tape), I would rather just fix it myself and be done with it. I'll post back what the outcome is in a few days after the inspection.

[TomR]

First, it would only be the sides of the boxes that would be sealed, so the cover plates could still be taken off and the boxes would still be easily accessible.

About the potential sparks...., I think that is one of the main reasons why electrical connections have to be made inside a junction box or other electrical box -- so that if there are ever any bad or loose connections, shorts, or sparks, they won't cause a fire by burning nearby combustible materials.

[clare]

They are box "extenders - basically boxes with no top or bottom