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Posted By: acetoday Customer Installed PVC - 10/25/04 09:38 PM
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.
Posted By: velect Re: Customer Installed PVC - 10/25/04 09:47 PM
I would never let a customer install any conduit, especially underground.
Posted By: Roger Re: Customer Installed PVC - 10/25/04 09:50 PM
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
Posted By: iwire Re: Customer Installed PVC - 10/25/04 09:51 PM
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
Posted By: iwire Re: Customer Installed PVC - 10/25/04 09:52 PM
Roger. [Linked Image]
Posted By: Roger Re: Customer Installed PVC - 10/25/04 10:10 PM
Bob, here we go again. [Linked Image]

Roger
Posted By: iwire Re: Customer Installed PVC - 10/25/04 10:20 PM
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. [Linked Image]

I consider myself in good company. [Linked Image]

Bob
Posted By: capt al Re: Customer Installed PVC - 10/25/04 10:22 PM
Is not most THHN also listed THWN and vice versa?

Al
Posted By: Roger Re: Customer Installed PVC - 10/25/04 10:47 PM
Bob,
Quote
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. [Linked Image]

It's almost erie at times. [Linked Image]

Quote
I consider myself in good company. [Linked Image]
and let it be known this is mutual. [Linked Image]

Roger
Posted By: iwire Re: Customer Installed PVC - 10/25/04 11:37 PM
MOB oh I mean Capt Al. [Linked Image]

Quote
Is not most THHN also listed THWN and vice versa?

I think you are correct. [Linked Image]

The reason many of us point out the need for a "W" type insulation is only to show off. [Linked Image] Well that and make everyone aware of 300.5(D)(5)

Quote
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
Posted By: capt al Re: Customer Installed PVC - 10/26/04 12:00 AM
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
Posted By: PCBelarge Re: Customer Installed PVC - 10/26/04 02:20 AM
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.
Posted By: ga.sparky56 Re: Customer Installed PVC - 10/26/04 03:42 AM
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. [Linked Image]

(Ducking for cover)

Russell
Posted By: Roger Re: Customer Installed PVC - 10/26/04 10:01 AM
Russell, no need to duck, being put in the same post with these three guys is quite the honor. [Linked Image]

BTW, Bob keeps his side of the dorm room pretty neat. [Linked Image]

Roger
Posted By: energy7 Re: Customer Installed PVC - 10/26/04 11:07 PM
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
Posted By: iwire Re: Customer Installed PVC - 10/26/04 11:21 PM
Very true energy7, luckily very few items are not marked as 75 C. [Linked Image]

Bob
Posted By: Active 1 Re: Customer Installed PVC - 10/27/04 12:38 AM
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
Posted By: Pat@Amber Re: Customer Installed PVC - 11/01/04 11:43 AM
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!
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