On Mar 18, 4:45*pm, "TomR" wrote:
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:http://www..grainger.com/Grainger/RA...050?Pid=search

http://www.grainger.com/Grainger/RAC...VU4?Pid=search

http://www.grainger.com/Grainger/RAC...-Box-Cover-5A0...

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.

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.