What is next size up for 50A subpanel?

[PoorOwner]

I was thinking of using 6AWG feeder and 50A breaker in conduit to feed a subpanel (max 125A, 8 space 16 circuit).

The wire distance needed is about 10 feet. I am thinking of going bigger but I am not sure what size is next? 4AWG feeder and what size breaker would that allow? Does ground wire need to upgrade from 10AWG as well, as I recall 10 ground is only good up to 60A feeds.

Also, does #4 wire requires a 1" conduit minimum?

 

[Aceman]

#6 thhn cu in conduit = 60 amp sub. #10 thhn cu green.

#4 thhn cu in conduit = 80 amp sub. 1" will work, we use 1.25" minimum, even at 10'. #8 thhn cu green

 

[pattenp]

If the subpanel is in the same building as the main panel have you considered to use SER cable? 2-2-2-4 Al SER will give you up to 90A. Not knowing your install situation you may or may not need conduit.

 

[PoorOwner]

Hey guys I just checked my panel (surface mounted), the biggest KO which I already knocked is 3/4" trade size, I think 1" EMT needs 1" KO.

It is ok to drill your own KO?

The main panel going into the wall cavity is pretty stuffed but plenty of KOs on the bottom. (both main and sub are surface mounted so I thought EMT and LBs are best to connect each other)

the other thing I didn't consider is I don't have a 1" EMT bender!

 

[Bert_]

#6 NM is rated 55A so it can be put on a 60A breaker.

As far as what size is next, here's your options. NM can't be higher than the 60* column, THHN 75*

 

[rburke65]

Aaahhh, that would be the 51 Amp. Panel! Sorry.... couldn’t help myself.

 

[PoorOwner]

I think I am going to pipe it with 1" PVC from the main panel bottom, to a LB into the wall, and meeting inside with a metal box with 1" KO, using a pair of 3/4" EMT, I will put the feed into the panel.

Since, I don't have a 1" bender or want to deal with IMC/RMC, and I don't have a 1" KO

I found out why there is not bigger KO on the subpanel, it was supposed to go on the top hub flange, but I used it as an exit (it is indoors)

 

[sberry]

Buy the HF step bit set, has a big one that can enlarge the hole for inch vs this booger box and separate 3/4 feeds.

 

[PoorOwner]

Can the step bit work on holes already punched out with nothing centering it?
it will just grab the hole and start reaming the next one right?

 

[sberry]

Yes, great for enlarging existing holes and the whole set is like 15$ or something, they are very good. Worth having. You can do this with a hole saw too, can do it with a pilot hole also but a unibit or step bit is faster and easier.

 

[PoorOwner]

Anything wrong with using PVC for a few feet indoors?

 

[sberry]

No, its legal.

 

[alfredeneuman]

Be sure to use Sch 80 PVC when it's subject to physical damage.

 

[PoorOwner]

Schedule 80? The 80 1” can only fit 3 4awg and putting the ground may go over 40% fill. Are there places below 8’ that won’t be subjecte to physical damage ?

 

[alfredeneuman]

Behind drywall or wood inside the wall.
Any surface mounting will require Sch80

 

[Bert_]

I don't agree that anything surface mounted is subject to damage or requires schedule 80. Emerging from a slab or maybe the bottom 2 feet of the wall might need schedule 80. Even then it would depend on other factors, just depends on the situation.

 

[sberry]

This is only from my experience. The code only says,, subject to damage which is subjective. Out in the world I have never had anyone look at the schedule, I did 20 of them before I knew it was a rule. The last service I did the guy was new to me, he grabbed the pipe that went from the bottom of the meter base to an lb that went thru the sill plate that was about 18 inches off the ground, made sure it was secure and didn't look at the pipe schedule.
I looked over a job a while back that was done by a handyman type. He had a couple issues but I opened a couple boxes and he had the grounds hooked together. I put some gfci and he had most of it tucked out of the way but for 1 piece around a column or something, it was about 10 ft up and low and behold the owner who is legally blind happened to find this 1 spot standing some 2x4's up against it and nicked the covering. I think I fixed it and nailed a cover piece over it.