Reduce wire

[OldeTimer]

I have a crazy situation where I have a number 2 wire that needs to fit on a 20a breaker that holds a max #10 wire. Any ideas? This is something I've never seen before. Appreciate the replies.

 

[roger]

Splice a smaller conductor to it

 

[augie47]

Pretty common in addressing voltage drop. Here most common solution is a polaris connector #2 to a short piece of #10

 

[don_resqcapt19]

Did you use a 2 AWG equipment grounding conductor as required by 250.122(B)?

 

[LarryFine]

Here most common solution is a polaris connector #2 to a short piece of #10

I wouldn't spend that much; I would just use a large wire-nut.

 

[curt swartz]

I wouldn't spend that much; I would just use a large wire-nut.

I have never seen a W/N listed for larger than #6.
I would use a Polaris or inline splice.

 

[LarryFine]

I have never seen a W/N listed for larger than #6.
I would use a Polaris or inline splice.

Okay, a split-bolt.

 

[winnie]

I have never seen a W/N listed for larger than #6.
I would use a Polaris or inline splice.

This will do the job:

https://www.etsy.com/listing/1660099584/giant-10-blue-large-jumbo-wire-nut

To the OP: the split bolt will be the cheapest way to make this splice, and learning to use split bolts is a good skill. But the 'polaris' style insulated set screw connectors mentioned cost more but are much faster to use.

https://www.homedepot.com/pep/ASI-14-2-AWG-Inline-Splice-Multi-Tap-Connector-Insulated-Black-AICD2-1/307768519

 

[brycenesbitt]

I just ran into this lovely wire:

Which is the wrong way to trim wire. That wire was installed in 1958, on a 70 amp breaker, with
the conductors trimmed to fit. That said in 67 years of service there's apparently be no problem.

 

[electrofelon]

Another option:

 

[brycenesbitt]

Another option:

Part number ?

 

[electrofelon]

Part number ?

Ilsco SPA-2, morris 90615, Burndy AMS2

 

[Joethemechanic]

I just ran into this lovely wire:
View attachment 2580801
Which is the wrong way to trim wire. That wire was installed in 1958, on a 70 amp breaker, with
the conductors trimmed to fit. That said in 67 years of service there's apparently be no problem.

That's ugly, but I've seen just as bad last a long time.

 

[herding_cats]

Okay, a split-bolt.

yup split bolt or split nut. You can get at home depot. Get some 6 mil rubber splice tape too.

 

[brycenesbitt]

When upsizing for voltage drop,
what section of the NEC specifically prohibits trimming stranded conductors?
Electrically it feel like there's more margin to using a trimmed stranded conductor with one connection point,
rather than the reducing tap that's three potential failure points.

 

[electrofelon]

When upsizing for voltage drop,
what section of the NEC specifically prohibits trimming stranded conductors?
Electrically it feel like there's more margin to using a trimmed stranded conductor with one connection point,
rather than the reducing tap that's three potential failure points.

Part of me is like its so hack to do that, and the other part is like what is the big deal? ITs probably better overall to trim in fact because you avoid a splice. With aluminum conductors, if you carefully cut around the perimeter with a sawzall blade, about halfway through a "ring" of strands, you can then bend and break them off and it ends up being super neat.

 

[Birken Vogt]

There is no way to assure that the trimmed strands have a tight connection to the untrimmed strands.

 

[electrofelon]

There is no way to assure that the trimmed strands have a tight connection to the untrimmed strands.

I dont understand, can you elaborate?

 

[ggunn]

I dont understand, can you elaborate?

I think he means that when you trim only some strands they can separate from the untrimmed strands back from the trim point

 

[winnie]

IMHO it is very very unlikely that there isn't pretty good conductivity between the various individual strands of a stranded conductor.

What you don't have is reliable assurance of such conductivity. At the terminations the strands are squeezed together in the lugs. But in the middle of the wire the strands are just laying together. I could imagine (unlikely, but possible) that water could wick into an aluminum wire and insulate the strands from each other.

What you also don't have is a tested mechanical connection. Another plausible failure mode is that the stress of the entire wire applied to the termination through only a few strands could lead to mechanical failure of the strands being used.

So my gut feeling is that trimming strands to fit terminations, for the case of conductors oversized for voltage drop, could plausibly work just fine, but that the installation is sketchy with untested failure modes, and not 'workman like'.