Conduit fill - Three #8awg plus one #10awg in 1/2 EMT?

[Jon456]

Any reason why you can't use the EMT as the EGC?

Technically, you probably can. As someone said earlier...

Anything can fail. The code does not generally require any special provisions for dealing with a failure.

But I would never use buried EMT as the EGC. In fact, I wouldn't use any buried metallic conduit as the sole EGC (that includes PVC-coated rigid conduit and stainless steel rigid conduit). Then again, I wouldn't use a bare conductor in any buried conduit as an EGC either.

 

[LarryFine]

About two years ago, I ran a 30a 120/240v feeder to a shed, using 1/2" rigid for minimal burial depth. Even though the conduit was properly bonded at both ends, I included an EGC. I happen to have some pics:

LB on house end in background:




Conduit through shed frame:




Ground rod right of conduit:

 

[Beaches EE]

Very nice Larry. It's robust, and with rigid if you're digging in rocky soil at least you don't have to go as deep as for PVC or EMT.

 

[winnie]

But I would never use buried EMT as the EGC. In fact, I wouldn't use any buried metallic conduit as the sole EGC (that includes PVC-coated rigid conduit and stainless steel rigid conduit). Then again, I wouldn't use a bare conductor in any buried conduit as an EGC either.

I think the bare copper would do just fine. If anything, the steel conduit will act as a sacrificial anode to protect the copper.

-Jon

 

[therobthompson]

It went!

Three #8awg THHN plus a bare #10awg in a 1/2" EMT

I think some extra steps really helped:

I cleaned and lubed the inside of the conduit with bits of rag tied on a pull string. First one soaked with 409, pulled through, more 409 at the far end and pulled back again. This yielded a good bit of dirt and grime. Then change rags and same process with acetone. Then same process again with conduit lube. So the pipe was as clean as possible and pre-lubed.

For the pulling head I stripped all the wires about 18", staggered the beginning insulation points by a few inches, cut the wires so their beginning points were staggered by 3" or so, tied 4 or 5 half hitches only on the stripped portion, and tape wrapped over all. This way the head had a very long gradual taper and never exceeded the diameter of the finished install, see photo.

I taped a radiator funnel over the entry conduit to make it easy to squirt lube into the pull. I got my son who can probably dead lift 500 lbs. to pull while I fed, keeping everything aligned and neat and squirting a whole quart of lube while it went.

As predicted the last several feet of the pull required a lot of force to get around the third bend, but around she went!

Thank you everyone here for the help.

 

[kwired]

Depending on neutral load you possibly could have helped the conduit fill by only using a 10 AWG neutral.

 

[Nuber]

Anything can fail. The code does not generally require any special provisions for dealing with a failure.

Agreed. Each repair option offered had positives and negatives associated with it. Glad to see the guy got it work without using my solution. I was merely providing a code compliant option, not necessarily the best one.