Sub-Panel Conduit Question

[J. Greg Jones]

I'm finalizing the plans for adding more capacity in my basement shop by adding a sub-panel and I have a question on conduit for the feed from the main panel to the sub-panel. The sub will be a 125a panel downsized with a 60a feed using (4) #6 THHN wiring. The sub will be about 5 feet from the main panel, on the same block wall, to put it where it will have the required access space.

My understanding that the minimum size conduit for (4) #6 is 3/4" and I thought about using 1" in case I ever want to go to #4 wire and bump the service to 100a. I originally planned on using EMT conduit, but if I understand the code correctly, I'll need to bend it to mount to the wall even over a short 5' run and I don't have the tools to do that. I could use PVC, but I'd still need to bend it with a heat gun, buy the glue, etc. just for this one-time project.

I was at Lowe's yesterday and I saw some moisture-tight, non-metallic flex conduit that looks like it would be perfect for what I want. For less than $10 I can get 5' of it in 3/4" and the necessary fittings to connect the panels-no bending, no glue, just simple. My questions on using this conduit are:

1) Would this be up to code and if so, any reason not to use it?

2) Is is available from an electrical supply house in larger diameters than 3/4", which is all Lowe's had on hand? I'd go with 1" if available.

3) Assuming it meets code, does it matter what material the wall hanger is (metal or plastic)?

One final question related to the sub-panel is where to have the feed enter the box. The panel is stamped "Line" on the top next to the largest knock-out, yet there are knock-outs on the side of the box that are up to 2" in diameter. I'd rather run the conduit as a straight line from the main into the side of the sub-panel, but I'm unclear if there is any code requirement to have the feed enter the top of the panel. Any thoughts on this?

Greg

[Andrew Thuswaldner]

Greg,
There are two sections in a breaker panel. The mains section, where the mains breaker is located, and the branch circuit section, where all of your branch circuit breakers are located. Your #6 feeder cable must enter the mains section only and not pass through the branch circuit section. The opposite is true for the branch circuit cables - they can only enter the branch circuit section. The breaker panel is typically oriented with the mains section at the top because in many cases the feeder cable more conveniently enters the panel from the top. But there are cases where the feeder cable is coming from below the panel and in this case, the panel can be installed with the mains section at the bottom.

I don't know if your local code allows you to use PVC indoors but provided that it does I suggest you consider it because it is easy to work with. You can cut the stuff with just about any saw or even used a pipe cutter if you want, the glue is not too expensive (just do it in a well ventilated area and don't inhale ;)). You can buy 90 degree elbows so you should be able to get from A to B in just about any circumstance.

I hope this helps,

Andrew

[Darrin Vanden Bosch]

You should be able to use 1" metallic flex, or even 1 1/4" and strap it properly and be code compliant as it would be under 6' long. The flex will more or less shape to the wall. You can get the material at an electrical supply house and they might be able to answer any questions you have.

Darrin

[Rollie Meyers]

Greg,
There are two sections in a breaker panel. The mains section, where the mains breaker is located, and the branch circuit section, where all of your branch circuit breakers are located. Your #6 feeder cable must enter the mains section only and not pass through the branch circuit section. The opposite is true for the branch circuit cables - they can only enter the branch circuit section. The breaker panel is typically oriented with the mains section at the top because in many cases the feeder cable more conveniently enters the panel from the top. But there are cases where the feeder cable is coming from below the panel and in this case, the panel can be installed with the mains section at the bottom.

I don't know if your local code allows you to use PVC indoors but provided that it does I suggest you consider it because it is easy to work with. You can cut the stuff with just about any saw or even used a pipe cutter if you want, the glue is not too expensive (just do it in a well ventilated area and don't inhale ;)). You can buy 90 degree elbows so you should be able to get from A to B in just about any circumstance.

I hope this helps,

Andrew

You cant use #4* wire for 100A , the ONLY exception is if it was dwelling service entrance and the same thing applies to #2 Aluminum all too small for a subfeed.

Mains section ??? That sounds like a Canadian panel. :D For those who dont know, Canadian panels are quite a bit different then the models used in the US market,more later...

* I am assuming this is a copper conductor.

[Jim O'Dell]

Hope the flex will work, code wise. It would be a lot easier. If it doesn't, I would check to see if the reason it needs to be bent and solid to the wall is so that it has support it's entire length. This seems the only logical reason, and I understand it's reasoning, if it is the reason. If so, can you anchor a piece of 2 X 4 to the wall that is cut to the right thickness so that the solid pipe comes straight out of one box and lays flat on the wood until it enters the sub panel's box? Would this suffice for the code?
And also I bet you could get the home store to bend a piece of conduit for you. Especially if you have to come out the top of the main box, and into the top of the sub panel box. If the idea above works, it would be a "U" shaped piece. Just mount it to the main box first, the position the sub panel under it to match.:rolleyes: At least that way the dimensions wouldn't have to be exact.
Just some rambling ideas. Jim.

[John Borysewicz]

This is my first post here, but the topic caught my eye. I added a subpanel in my garage a couple of years ago and went with exposed metal conduit for the circuits. Rather than bending pipe, you can buy pre-bent sections and angular fittings that will allow you to do what you need. It's not pretty, but it does the job. And it's not real expensive.

[Rob Russell]

There are also PVC conduit bends that get glued together - the big box stores sell them.

I agree with Rollie about the conductor sizing. In conduit you could use #3 copper or #1 aluminum.

If you can use Schedule 40 PVC, you'd need 1 1/2" to take (5) #1 AL conductors. I know that the Equipment Grounding Conductor can be smaller, but I'm too lazy right now to calculate the required conduit size for (4) #1 AL + (1) #4 AL.

[Bruce Wrenn]

Using the #4 copper, you could put in a #10 ground wire, if memory serves me correctly. If you know any "pipe jobs" going on in you area, you could probably get EMT bent for a "six pack." Just measure the distance, face to face between the panels. Don't fasten sub to wall, until your EMT has offsets bent. This way you know it will fit. Inspector may or may not require insulated bushings on each end of EMT.( Some require them on PVC- DUH?) Don't forget to buy TWO grounding bars, one for each side of the panel. It makes wiring easier.

[Rollie Meyers]

Using the #4 copper, you could put in a #10 ground wire, if memory serves me correctly. If you know any "pipe jobs" going on in you area, you could probably get EMT bent for a "six pack." Just measure the distance, face to face between the panels. Don't fasten sub to wall, until your EMT has offsets bent. This way you know it will fit. Inspector may or may not require insulated bushings on each end of EMT.( Some require them on PVC- DUH?) Don't forget to buy TWO grounding bars, one for each side of the panel. It makes wiring easier.


W/ #4 copper a 8 AWG Green insul. or bare equipment grounding conductor is required, plus any conduit fitting w/ #4 AWG or larger needs a bushing. BTW, any grounding conductor 6 AWG and SMALLER if insul. needs to be green colored, taping it is not acceptable per NEC rules.

[J. Greg Jones]

Thanks for all the helpful suggestions. I've decided to go with the EMT conduit. For this small job, it's more pricy than PVC or flex, but I know that there should be no problems with EMT passing inspection. I'm going to my local electrical supplier to see if they can/will bend it for me. Otherwise, I'm going to see if I can rent a bender or buy a cheap one at HF.