supply conductor temperature of Aluminum cable?

[Joe Neidar]

Hi,

Does anybody know if there is a way to check what temperature an aluminum cable is rated for? The cable is 12 AWG NM aluminum. It doesn't give a temperature on the sheathing, but it does say 600 V.

Yeah, I got a new lamp and it says warning 'min 90C supply conductor'. I did a google search and the only thing I could come up with was for 14 gauge copper.

Thanks for any help.

oh, yeah, since I'm asking, is it true that I don't need any special wire nuts or connectors for this? I know it's required for connecting supply cables e.g. 12 Al to 14 Cu. Perhaps it's a dumb question, but I thought I'd double check.

Thanks again,

- Joe

[Greg]

Type NM is 60c conductors.

[Doug Miller]

This is not correct. The *cable* is rated at 60C, but the conductors themselves are 90C:

"Conductors shall be rated at 90 C. The ampacity of Types NM and NMC cable shall be that of 60 C conductors..." [1993 NEC, Article 336-26]

[Doug Miller]

The NEC requires 90C-rated conductors in type NM cable.

Not a problem.

No, that's not true. You need wire nuts that are approved for use with both aluminum and copper, and an anti-oxidant compound as well.

[Greg]

Nope NM-b is 90c. He said NM, which has type TW conductors in it (60c) and since it is aluminum that pretty much dates it prior to ~1985 when NM-b with the THHN was cut in.

[Joe Neidar]

[e-mail] (Doug Miller) wrote in news:%xsPc.2123$ [e-mail]:

Really? I was told the expansion of larger and smaller wire gauges wasn't such a big deal.

Anyway, assuming my supply wires are NOT 90C rated, can I pigtail the aluminum wires to some NM-B (or other 90C rated cable) with the ridiculously expensive Al-Cu wire nuts and anti-oxidant compound? Would that satisfy the temperature rating? How long should the pigtails be?

Thanks,

Joe

[zxcvbob]

What exactly are you connecting to; wires leads coming out of the fixtures, or terminal screws?

Assuming it's wire leads, I'd probably squirt deoxidizer paste into a wirenut and fasten it on the AL wire and the fixture wires really tight. It's a light fixture, not a receptacle; the current is limited by the lamp to about 1 amp. (could be more, could be a lot less, but it's not gonna be 15A)

If it's terminal screws that are not rated for AL wire, I'd do that copper pigtail thing. Six inches, or whatever length is easy to work with.

Bob

[Greg]

If you end up pigtailing and the 60c is in the same box as the fixture base you haven't really fixed anything. They are just covering their ass for people who don't believe the "60w max" warning. Is the insulation baked? If you are just pigtailing with purple wirenuts I would skip it and hook up he fixture directly with a purple.

[Joe Neidar]

[e-mail] (Greg) wrote in news: [e-mail]:

The fixture is a 22 W fluoresent with a circline T-9(?) bulb. It says to use only 90C supply wiring.

Incidently, the wiring on the old fixture (which was ancient and I assume rated for the wiring) was rather crusty looking.

I don't know, maybe I'll just return it and get something that isn't so picky.

[Greg]

They put that sticker on all of them. Lawyers. The 22w should not be a problem at all

[Joe Neidar]

[e-mail] (Greg) wrote in news: [e-mail]:

yeah that's what I thought (22W), but I went ahead and picked up a couple different fixtures just to have an alternative. None of them said anything on the box about wiring temperature, but on the inside of one it said the minimum temp was 85C (as opposed to 90C) as if to taunt me. The other one has a warning in the install instructions (homes before 1985 have 60C wiring blah blah) but doesn't say the fixture has any special requirements (and the fixture doesn't have a sticker or anything) so hopefully it actually doesn't and not they forgot to label it.