1) There is a special lug INSIDE the forming shell for this termination.
If your light is that old it may not be there and I am not sure what you could do. Without this lug you may be SOL.

2) At a REAL electrical supply house. It is made by 3M and is a grey epoxy type of substance.
NO, it cannot be used under water.

3) Your "electrician" is wrong and obviously does not know pool codes very well. Galv is NOT an approved conduit. You need brass or bronze, or PVC.

Replacing the section of brass would be the only proper way to fix it. You will never get a #8 and the light cord through a 1/2" brass conduit. Dont know where you live but call one of smaller local pool builders and find what company they use for their electrical installs. Let them fix it, or ask them where you can pick up a piece of brass from. You will have to cut and thread it of course. If it is a center section then you will need a brass union.

I agree that replacing the brass is the better way to go, but I don't see where he states this is 1/2" conduit. Typically it is 3/4" and there is no problem with the cord and a #8.

Just a assumption. Brass is very expensive, I dont know of anyone, or any reason you would take 3/4" to the niche. Different areas, different set of standards. That may be how they do it in your neck of the woods.

I have NEVER seen anything but 3/4" (or even 1") from the deck box to the niche. Every niche I have ever seen has had a 3/4" hub. If they use 1/2" brass and reduce it down in your neck of the woods then they obviously have enough money to do it RIGHT and use 3/4".

I have not seen brass used in many years. 20 years ago on LI that's all we used.

Using 1/2" PVC and reducing the hub down is foolish because you are correct, you'd never get the cord and #8 in there.

Not that it matters to this post, but niches come in 1/2, 3/4, and 1" hubs.
everything they do in AZ is brass, and 1/2". No ruducing anything.

Interesting. I've never seen 1/2", then again, I've never bought one either.

If all you do is brass then 1/2" would not matter. Although getting the cord in a long run must be fun.

Thanks for the discussion. I'm still left with my problem. I did discover that I have enough brass conduit left if I can straighten out a section, add threads to a couple of ends, and join some pieces. Is this possible and who could do it - plumber or electrician. If have have to scrap the brass and go with PVC can't I just run an external bond wire from the existing brass conduit that comes from the niche to the junction. There's already some bonding wire attached to the brass conduit with a bracket and the new junction box has an external terminal? Wouldn't this just do what the continuous brass did anyway? I'd just have some PVC joining the existing brass conduit and the junction box all externally bonded together with bonding wire...please help. I can send pics to anyone that can help!!! jcoelho@hotmail.com

No, you can't do that. I mean you can, but it would NOT be correct, or safe IMO.

The external bond is part of the bonding grid. The bond inside the conduit is only to bond the PVC pipe and connects inside the deck box. The bonding grid has no connection to the deck box, and there is no place to connect to to it externally.

Thanks. So, I have a section of 2/3 brass conduit from niche to the surface, and now need to extend the conduit to the junction deck box. I want to do it in the proper manner. It appears my best bet is to find someone who is capable of rethreading and using my sections of brass conduit. Is this a possibility? Any other suggestions.

is there a home depot near you, you can have them thread the pipe, it is the same thread as the gas pipe, only the metal is softer, they also sell brass couplings, and a brass union if you need it.

Plumber rethreaded existing conduit, cut, theaded, and joined other pieces. Had my electrical inspector stop by and provide guidance. He said the connected conduit would be fine; could use a small curved peice of galvanized to connect exposed (coming out of future concrete) brass conduit to junction box - so all but a small part will remain brass and the galvanized will be joining the box to the brass. The other method would be to try to use another brass nipple to a 90 degree brass, to a brass nipple, to junction box but I don't think I'll get the wire pulled throught the 90. My other issue is to ensure the bonding grid is bonded to the wire mesh the concrete contractor will use for the deck. Where can I get brass hardware to attach a #8 bond wire to the mesh? Can I use bronze split bolt connectors? I also want to replace a 3/4 pipe bonding clamp on the light conduit and a 5/8 rebar clamp before pouring the concrete. Of course I'll also need to bond my diving board and ladder again. Just having a hard time finding the proper connectors...! I can probably get the pipe and rebar clamps but I'm not sure exactly what I need to bond the concrete deck metal mesh material. Any suggestions? Thanks.

I have a similar project and came across this discussion. It seems like you have repaired your pool light. I am looking into doing the same for mine. My 1/2 inch brass conduit looks to be collapsed under a long patio section (cannot get fish tape through, end of wire I pulled out looks to have been improperly spliced at some time in the past, under the deck!) and i am looking to replace / reroute. I have found a source for the brass 1/2 inch schedule 40 c230 pipe as well as a threader and bender at Amazon. Have a question about your brass unions of which I will need several due to the length. I assume they were NPT self sealing threaded and the unions themselves are sufficient for ground continuity? Were additional straps needed? Also, did you need to bend the pipe? If so, what tools did you use?

pacificdune, you DO realize this thread is just over four YEARS old, right?
It is extremely rare that folks come back after their problem/project is done.

First off, as stated, it is highly doubtful that you have 1/2" conduit. Are you absolutely sure??

Second, Where would you need straps for an underground installation? If you need them it is still rigid electrical conduit. Straps for the appropriate size rigid conduit will work.

Bending conduit is not exactly something for a DIYer, especially brass conduit. I'd get pre-made 90 deg sweeps.