PVC direct bury

[brantmacga]

It is sad to see the extra expense being added to a project, where the client asking the contractor to keep the expenses down.

I've got one even more ludicrous for you. The site lighting specs for one of the restaurant brands we build are:

1" RGS from the panel to EACH pole. These are LED fixtures, about 200w ea. They require #10 wiring for 0'-80'; over 80' they want #8 THHN. Usually 6-8 poles per site with one fixture each.

 

[kwired]

I've got one even more ludicrous for you. The site lighting specs for one of the restaurant brands we build are:

1" RGS from the panel to EACH pole. These are LED fixtures, about 200w ea. They require #10 wiring for 0'-80'; over 80' they want #8 THHN. Usually 6-8 poles per site with one fixture each.

Specs are likely between engineer and the franchise. Franchisee is who pays for things and likely has no choice but to follow franchise rules and specifications.

Design probably based on boiler plate plans that maybe made sense on some worst case situation site.

 

[Eddie702]

I like @oldsparky52 s Idea. Quote the job as specd with 80, quote a deduct for 40.

Then your covered by submitting you bid as specified also letting the engineer know there is an alternate for cost savings. It will also bring to their attention that they should check all bids to make sure all bidders are using 80 as specified.


The code is the minimum the engineer has every right to ask for more......but he has to justify that to the owner

 

[ggunn]

We are currently estimating a project, the Engineer drawing up the prints has us installing Schedule 80 PVC underground with sand bedding. We asked the question why Schedule 80 and not schedule 40. His reply was, because schedule 80 was rigid and schedule 40 was not. He would be okay with schedule 40 but, we would have to cover it with a flowable fill or concrete this way it would be protected from damage. We sent him the code reference for PVC (Article 352) and he came back with, schedule 40 underground and it needs to be covered with flowable fill not sand.

Is there any way, to get the NEC reference 352 (G) to spell out Schedule 40 can be installed underground with native fill, sand bedding, or concrete encasement? Instead he is reading underground encased in concrete is the only way you can install it. His reply to our questions was; Schedule 40 shall be used in lieu of Schedule 80 for the duct banks.
How can we get the Code reference changed, to be more descriptive of the back fill? ie... Schedule 40 approved for direct bury / underground with native soil, sand bedding or concrete encased back fill.

How long is the run, i.e., how much of an added expense is the sch80 over sch40? Some things are not worth fighting about.

 

[petersonra]

The owner has the right to spec a job to a higher standard than an NEC code minimum standard.

yep. he can pay to have the conduit painted pink if he wants it that way.

personally, I am kind of a fan of using schedule 80 PVC over schedule 40. the schedule 40 stuff seems kind of flimsy to me and there is little difference in cost. but underground???

 

[oldsparky52]

yep. he can pay to have the conduit painted pink if he wants it that way.

personally, I am kind of a fan of using schedule 80 PVC over schedule 40. the schedule 40 stuff seems kind of flimsy to me and there is little difference in cost. but underground???

If they want to pay for it. My money says the owner is not aware of this.

 

[hillbilly1]

If your installing it in Evansville, Indiana, be sure to use purple primer! Had a inspector walk an entire parking lot making sure every joint was primered! LOL!

 

[kwired]

yep. he can pay to have the conduit painted pink if he wants it that way.

personally, I am kind of a fan of using schedule 80 PVC over schedule 40. the schedule 40 stuff seems kind of flimsy to me and there is little difference in cost. but underground???

Around here we use a lot of thin walled PVC pipe (not listed) with direct bury conductors inside especially on farms for long runs. The main reason is rodent protection, but seldom ever have trouble with collapsed pipe. We do transition to sch 40 or 80 as necessary when emerging from underground or running under a slab/building, etc.

 

[electrofelon]

If they want to pay for it. My money says the owner is not aware of this.

Exactly. However if you look back at the OP, it sounds like it's not because the engineer thinks it's better and worth it, but because he is misinformed about the requirements (or lack there of) for 40 underground.

 

[tortuga]

In that case I think everyone will agree that Sch 80 long radius bends would have been much better. Or maybe even RGS elbows.

My guess is that the same people who criticize engineers for spec'ing anything above the code are going to be the first ones to go to the owner blaming the engineer when something like that happens.

Seen it happen. Lots of EC's are very used to designing to the NEC and bid on municipal projects not reading the specifications.
Pete your at least reading the specs, a local EC here went bankrupt on a bridge lighting project due to installing the wrong conduit and wire. It met NEC (EMT and THHN/THWN) but not the specs (XHHW-2 and IMC)

 

[oldsparky52]