Has anyone tried to install 4 conductors of # 6 THHN copper in 1 inch PVC. It's approximately a 70 ft run with 3 nineties and two offsets.
My customer had insisted on installing this portion to save money even though I told him to use 1 and 3/4 inch PVC.
I know the code allows up to 4 conductors in 1 inch PVC, and not more than 3 90's. However, I was forced to install two offsets due to knock outs not lining up.
I'm concerned I'll run into major problems when I pull this wire. I may even ask the customer to install 1.5 inch PVC to make it easier.
Any suggestions would be greatly appreciated.
I would never let a customer install any conduit, especially underground.
Ace, this shouldn't be a difficult pull.
6 number 6 THHN conductors are allowed in 1" PVC, and the 2 offsets shouldn't exceed 360 deg when added to the 270 deg of the 3 90's
Roger
OK
First I would mention that if this run goes underground you need THWN.
Moving on, five or six - 6 AWG THHNs are allowed in 1" PVC. It depends if you are using schedule 80 (five wires) or schedule 40 (six wires)
The NEC allows 360 degrees of bend between pull points, three 90s and two offsets should be fine unless you made you offsets sharp.
I do not see a problem with this pull, although I would definitely use wire pulling lube, you can get small containers of it at any decent supply house. I like Dyna blue pulling lube it cleans up easy.
Bob
The inside joke here is that Roger and I have a strange habit of answering the same posts at close to the same moment with very similar answers.
This has happened many times here and elsewhere.
I consider myself in good company.
Bob
Is not most THHN also listed THWN and vice versa?
Al
Bob,
The inside joke here is that Roger and I have a strange habit of answering the same posts at close to the same moment with very similar answers.
This has happened many times here and elsewhere.
It's almost erie at times.
I consider myself in good company.
and let it be known this is mutual.
Roger
MOB oh I mean Capt Al.
Is not most THHN also listed THWN and vice versa?
I think you are correct.
The reason many of us point out the need for a "W" type insulation is only to show off.
Well that and make everyone aware of 300.5(D)(5)
300.5(D)(5) Listing. Cables and insulated conductors installed in enclosures or raceways in underground installations shall be listed for use in wet locations.
Bob
Bob, you can call me an MOB anytime. Showing off can be a good thing when you are right. 300.5(D)(5) is a good point to remember also.
Al
The difference of the "THHN or THWN" type conductor is the temperature rating of the conductor for ampacity rating.
If you use the "THHN or THWN" conductor (dual rated conductor) for underground, you can only use the THWN using the 75*C column of table 310.16, even for ampacity adjustment.
Example: 2 AWG THHN is rated for 130 amps at 90*C, 2AWG THWN is rated for 115 amps at 75*C.
Bob and Roger are actually College students who room together,and hatch this stuff up.
I think they learned it from two other guys named Ed and Bennie,who went to the same College.
(Ducking for cover)
Russell
Russell, no need to duck, being put in the same post with these three guys is quite the honor.
BTW, Bob keeps his side of the dorm room pretty neat.
Roger
Per PCBelarge' comments:
don't forget that the "weakest link" in the circuit governs. The terminals at equipment usually are rated at 60oC or 75oC, so that is the limitation on ampacity. i.e. Column to use in Tbl 310-16ff.
(310.15(B)FPN1
Very true energy7, luckily very few items are not marked as 75 C.
Bob
One time a customer did not want to wait for us so he ran 1 1/4 plumbling pvc. Nothing was glued together. He used plumbing elbows for bends. Under a new brick patio and 1/2 wall.
Tom
The "plumbing pipe" thing happens to me all the time. Customers call me after they have poured the patio and tell me they already installed the pipe for the hot tub to make things "easy" for me. It's usually 1/2 inch plumbing pipe and fittings no where close to where I need them. Thanks for the help!