Need help to determine 8awg from 6awg XHHW AL

[Mgarf33]

I’m working on a job and can’t see the wire labeling inside the wall, only the individual wires with the sheathing stripped back. I’m trying to determine whether it’s 8 or 6 awg. Is there a way to measure it. There’s 7 strands, but I believe both sizes have 7 strands. From what I’ve read the outer diameter is only about 1/32nds difference, no?

 

[infinity]

If you cannot measure it with something like a micrometer get a scrap piece of each size and compare it to what you have.

 

[Coppersmith]

I've been wanting to buy a wire gauge for just this reason. They are hard to find.

 

[Frank DuVal]

Here is a cheapie:

https://www.amazon.com/Whitelotous-...ocphy=9008196&hvtargid=pla-569821731309&psc=1


And a more expensive version:

https://www.zoro.com/mitutoyo-gage-wire-0-36-range-950-202/i/G3118333/

Or just get a dial caliper (never needs batteries like the digital version) :

https://www.harborfreight.com/6-in-dial-caliper-63730.html

But this takes up way more room in the truck then the simple flat gauge.

 

[Mgarf33]

Checked the outter insulation diameter to be about .28-.29”. I’m assuming this is 6awg, but I can’t figure out why they installed 6awg and used a 30A breaker? This is for a larger 4 ton AC unit, I can’t imagine a 10 SEER 4 ton unit had a max fuse of 30.
They had some minor additions and the system never keeps up so we’re going back with a 5 ton with min amp of 37A, max fuse 60A. So, I guess Im good even with 8awg, but I’d be more comfortable knowing it was 6awg.

Was it common practice to oversized the conductor to an AC unit disconnect from the panel in the late 1980’s.
I know these days they only run the minimum conductor size per min amp rating of the equipment.

 

[Mgarf33]

Crap, I found an old piece of 8awg XHHW at my house, and it was on a 30A breaker as well. it’s the same outter diameter.

 

[StarCat]

HVACR Breakers

HVACR Breakers

Checked the outter insulation diameter to be about .28-.29”. I’m assuming this is 6awg, but I can’t figure out why they installed 6awg and used a 30A breaker? This is for a larger 4 ton AC unit, I can’t imagine a 10 SEER 4 ton unit had a max fuse of 30.
They had some minor additions and the system never keeps up so we’re going back with a 5 ton with min amp of 37A, max fuse 60A. So, I guess Im good even with 8awg, but I’d be more comfortable knowing it was 6awg.

Was it common practice to oversized the conductor to an AC unit disconnect from the panel in the late 1980’s.
I know these days they only run the minimum conductor size per min amp rating of the equipment.

You need the MAX Breaker size for a single phase condensing unit. Especially one without start gear.

 

[kwired]

keep in mind compact conductors will have smaller diameter than non compact conductor of same AWG.

Don't know if I have ever seen 8 AWG aluminum, strands would be getting pretty small (for aluminum) if stranded. Pretty sure I never seen 10 AWG aluminum in anything but solid conductor.