14-50R range outlet with aluminum SE cable in plastic box. Need avice please.

I need some advice about installing a breaker and receptacle on some 6 gauge cable that was put in when the house was being built. I am comfortable with the usual 120V stuff but this heavy cable is beyond my experience and I really need some help (and I will hire an electrician if need be but I want to understand exactly what I should expect).

In my garage I have a plastic 35 cubic inch box (Slater S235RAC) fed with 6 gauge aluminum SE/SER cable (Zaner Wyatt AA8176 compact aluminum). In the box all conductors are wire nutted and in the panel (Siemens) the neutral and ground are connected but the hots are wire nutted (no breaker installed). I have a Siemens QP 50A breaker and Leviton 14-50R receptacle, both rated CU-AL and 75C. Here are my questions:

1. Someone who works for an electrical contractor (but I don't know if he's actually an electrician himself) told me that you can't use a plastic box with SE type cable. Is this true? If I need to replace the box with metal, is it possible to extract the plastic box and install an old work metal box without cutting drywall and/or screwing up the cable? If this needs to be done specific box and or technique recommendations would be helpful. I sure hope this isn't the case.

2. If a plastic box is ok, is 35 cubic inches big enough? I don't know if the clamps on this box count as internal or external, and I'm not completely sure I understand how to do the calculation for this kind of receptacle. The front of the box is set back a little from the drywall so I think I could use an extension ring (I see my local store has a Carlon plastic box extender marked 7.4 cubic inches). EDIT: OK, so I think the 6 gauge wire counts a 5 cubic inches (20 total), the receptacle counts as 4 wires because it doesn't fit in a 1-gang box (20 more = 40), and the clamp counts as internal (5 more = 45). So I would need 10 cubic inches worth of extension rings. Is that correct, and if so can I use 10 cubic inches worth of extension rings? Can I double them up, and can they stick out from the wall surface? Again this is all assuming a plastic box is ok in the first place.

3. Does anti-oxide grease need to be used on the wire? I have two other circuits using aluminum wire and I can't see any grease on them, but I don't know how obvious it would be.

4. Is the torque so important with aluminum cable that special tools are needed, or can I just get it good and tight with a regular screwdriver?

This came to pass because the builder owed me a small refund and I asked him to put in the cable instead just in case I ever wanted it; the cable was run (based on a photo I have) days before the date on my panel inspection sticker so it should all be good in terms of permitting and I don't think this would be considered a new circuit. House was built under 2005 NEC. Now I need to sell the house and my realtor says people will be scared of an unfinished circuit because most people don't understand electricity very well (and I guess maybe I don't either or I would be here asking all these questions. ). Thank you for any help you can give me.

 

Plastic boxes can be used with SER cables with the proper clamps.

Each #6 is 5 cubic inches. I don't remember the allowance for the device. I believe it would be 4 allowances.

No-alox does not need to be used, but is a good practice.

I don't know why your Realtor is worried about a blanked off wire in the wall.

Proper torque is always the proper way.

 

Do you know if the box I have has proper clamps for SER? And if there's a way to extend the box to from 35 to 45 cubic inches (if I'm correct that the clamps count as internal)?

Thanks!

 

We have no idea what box you have. Can you post a picture?

 

I am assuming by wire nutted you mean that each wire is individually capped with a single large wire nut. Keep in mind that aluminum wires CANNOT be spliced with any type wire nut. The cable needs to be protected at 40 amps, you'll need a Q240 breaker if you connect this circuit.

I agree with PCboss, if the box has a proper blank plate and the circuit is not connected in the panel I'd just leave it alone.

 

According to post #1, this is the box he has:

Switch & Outlet Box, S235RAC | by Legrand

 

Yes, that's what I meant. Not that the wires are wire nutted together.

I'm thinking that's a good idea.

Of course. I guess what I was wondering is if electricians typically use torque screwdrivers or do they just crank down with a screwdriver. Kind of like how all cars have lug nut torque specs but good luck finding a professional mechanic who will use a torque wrench on lug nuts.

The cable is rated for 75C and the builder/electrician assured me that it could be used for 50A. Why do you say 40? I think the 2008 NEC said SE cable can only be used at 60C for interior applications but the house was built under 2005 and my understanding is that the newer code has relaxed that.

 

Oh, and also, my ovens are wired with exactly the same cable and those are on a 45 A breaker, so I hope it's good for more than 40 A.

I am planning to tell potential buyers that they can use it for a 50A circuit, so if that's wrong please explain why.

 

Thanks for posting the link to the box Wirepuller. I have never tried to use those clamps on a cable that large so I am not sure it would pass based on that alone. I think it is also too small volume wise.

The temperature rating is going to be based on whatever code it was installed under.