Metal conduit size

JJJJ · May 21, 2023

I am planning on running two 4 awg wires and a 6 awg ground in metal conduit.

Originally I was planning on using one inch conduit since this is the outlet size from the breaker box.

My original plan was to fish the wire through a little at a time as I piece things together primarily because there will be a number of bends.

The total distance will be about 20 feet.

The two 4 awg wires side by side are just shy of 3/4 inch. The thought was to place the 6 awg on top between the wires.

Before I buy any more conduit and components am I mistaken to think that one inch would work?

goldserve · May 21, 2023

You can use this calculator to add different size wire. Fill < 40% will work. It will automatically bump you up to next size.

Conduit Fill Calculator | Southwire

Get accurate conduit fill percentages with Southwire's Conduit Fill Calculator. Perfect for electricians, engineers, and contractors.

www.southwire.com

JJJJ · May 21, 2023

Nice. I am not familiar with some of the abbreviations used in the app

timselectric · May 21, 2023

1" is what you need.

JJJJ · May 22, 2023

I am looking at my wire choices. I have some 4 awg welding wire from a previous purchase. Can this be used in metal conduit or is THNN required?

Just curious.

timselectric · May 22, 2023

JJJJ said:
I am looking at my wire choices. I have some 4 awg welding wire from a previous purchase. Can this be used in metal conduit or is THNN required?

Just curious.

The jacket is to rubbery and stretchy. (Highly technical terms) it won't be easy to pull through conduit without risking damage,

Solarisium · May 22, 2023

JJJJ said:
I am looking at my wire choices. I have some 4 awg welding wire from a previous purchase. Can this be used in metal conduit or is THNN required?

Just curious.

Use wire lubricant to make it easier and faster to pull wires through conduit.
I used a few drops of lubricant on the wires. It made a good difference.

EastTexCowboy · May 22, 2023

Personally I would avoid the welding cable in conduit for the reasons given by @timselectric plus it's just not as rigid, but definitely use some wire lube as @Solarisium said. I use way more than a few drops myself. Wire lube is relatively cheap so don't be stingy with it! ?

timselectric · May 22, 2023

Wire lube is a game changer, for long pulls.
But, welding cable is still not going to be a good idea.

JJJJ · May 22, 2023

timselectric said:
Wire lube is a game changer, for long pulls.
But, welding cable is still not going to be a good idea.

Point taken. Perhaps can use for another project.

THNN vs fine stranded. THNN has benefits of smaller diameter and less expensive. Tradeoff is stiffness. Suggestions?

timselectric · May 22, 2023

JJJJ said:
Point taken. Perhaps can use for another project.

THNN vs fine stranded. THNN has benefits of smaller diameter and less expensive. Tradeoff is stiffness. Suggestions?

THHN stranded

timselectric · May 22, 2023

Forgot we are talking about #4.
It's undoubtedly going to be stranded. lol

EastTexCowboy · May 22, 2023

I'd probably go with something like this for a short run like you're doing -

Southwire (By-the-Foot) 4 White Stranded CU SIMpull THHN Wire 20500599 - The Home Depot

Southwire type THHN or THWN-2 conductors are primarily used in conduit and cable trays for services, feeders, and branch circuits in commercial or industrial applications as specified in the NEC 2. When

www.homedepot.com

But then again, you can get a lot better per ft price if you buy something in precut lengths like this -

https://www.amazon.com/19-Stranded-Black-Copper-Building-Wire/dp/B08PZCL4QB/ref=sr_1_3?crid=IW9TQFPTA6GJ&keywords=4%2Bawg%2Bthhn%2B50%2Bft&qid=1684766093&s=industrial&sprefix=4%2Bawg%2Bthhn%2B50%2Bft%2Cindustrial%2C109&sr=1-3&th=1

I have a bunch of 4 awg (and everything else it seems) lying around left over from projects. You likely will have as well pretty soon.

But seriously, if I need 25' of something and I can buy a 100' roll for less than double the by the foot price I just buy the roll because I know I'll probably use it. For anything like 14 awg to 10 awg I just bite the bullet and buy the 500' spools. It has saved me a ton of money over the years.

JJJJ · May 22, 2023

The reason I asked about THNN vs stranded is I anticipate four 90 degree bends and remember the “joy” of working with THNN in tight spaces when wiring the MPPT and breakers

timselectric · May 22, 2023

Pro tip
Apply the lube to the wire, not the pull rope.

EastTexCowboy · May 22, 2023

JJJJ said:
The reason I asked about THNN vs stranded is I anticipate four 90 degree bends and remember the “joy” of working with THNN in tight spaces when wiring the MPPT and breakers

Definitely be generous with the wire lube. No farther than you're going you might consider 1 1/4 conduit and swept 90s as the cost wouldn't be that much different and it would give you lots of room, but I think you can pull it in the 1 inch if you make up a good tapered head and lube the wire good. I use mule tape for pull rope.

timselectric · May 22, 2023

Mule tape (aka flat rope) is the better choice.
Because it doesn't cut into PVC like a round rope will.

JJJJ · May 22, 2023

Thank you very much for the recommendations. Very much appreciated!!!

EastTexCowboy · May 22, 2023

JJJJ said:
Thank you very much for the recommendations. Very much appreciated!!!

One last thing. if you can get someone to push while you pull it makes ALL the difference. Short pull so not mandatory but if you have someone handy I'd so so.

MarkSolar · May 22, 2023

You're right at the limit, NEC limits total bends in one run to 360 deg.

Metal conduit size

Aspiring apprentice

Solar Enthusiast

Aspiring apprentice

If I can do it, you can do it.

Aspiring apprentice

If I can do it, you can do it.

New Member

Solar Wizard

If I can do it, you can do it.

Aspiring apprentice

If I can do it, you can do it.

If I can do it, you can do it.

Solar Wizard

Aspiring apprentice

If I can do it, you can do it.

Solar Wizard

If I can do it, you can do it.

Aspiring apprentice

Solar Wizard

Solar Enthusiast

Similar threads