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#53532 06/28/05 05:07 AM
Joined: Jun 2005
Posts: 124
P
poorboy Offline OP
Member
Running secondaries underground from pad mount x'former to a CT cabinet on the back outdoor wall of a mall store. Coming out of the ground on the building end up to the cabinet I am planning to use sch.40 PVC. Bollards protect the service from vehicular traffic. There are two 4" conduits and there will be less than 3 feet exposed from ground level to bottom of cabinet on the building end.

Does the code allow this use of PVC? Is the definition of physical damage the deciding factor?

#53533 06/28/05 06:31 AM
Joined: May 2001
Posts: 717
G
Member
The code does allow this, and you are correct that damage is the deciding factor.

Sometimes the possibility of damage is what decides FOR PVC. We quit using metal channel up poles in this area because if the cable underneath were crushed into the channel, it would keep arcing and burning, often onto a wrecked vehicle with injured occupants and gasoline. We decided that it would be better to have the cable severed, and firing into a non-conductive material NOT producing arcs. Lotsa folks disagree with this, but it also takes care of a rust problem.

The first time ya feel like a geezer is when you go back to a service you built from rigid and made a piece of artwork out of it, only to find it rusted to pieces and dangerous.

NOTHING wrong with PVC, It'll likely outlast anything else you would put out there. Consider Schedule 80 though (yes 40 is legal), it's the difference between rigid and emt.

#53534 06/28/05 12:13 PM
Joined: Mar 2005
Posts: 399
A
Member
Check with the inspector before you use the schedule 40.
Many inspectors require schedule 80 if it is exposed coming out of the ground regardless of bumper poles.
The underground run can be 40 and then switch to 80 for the stub up.
Small cost difference, big headache to make changes.
Alan--


Alan--
If it was easy, anyone could do it.
#53535 06/28/05 07:04 PM
Joined: Jan 2003
Posts: 1,429
L
LK Offline
Member
"Bollards protect the service from vehicular traffic."
_____________________________________________
Hope these are not Lighting Bollards they will not protect anything, we noticed this in back of a bank.

They made us install a curb, and footing for the rail support, every area has it's own rules on this , best to check first.

[This message has been edited by LK (edited 06-28-2005).]

#53536 06/28/05 08:40 PM
Joined: Jun 2005
Posts: 124
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poorboy Offline OP
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No, they are what Alan prob is referring too as "bumper poles". 6" steel poles in 18" sonatube full of concrete. Which brings up another interesting point...why do they always wait till just before paving to bring in the auger truck and drill these holes? They are 5 or 6 ft deep and the ground is full of gas, water, and elec pipes. They corkscrewed thru a 1" water line this week requiring a large excavation to fix. Thankfully they asked me to spot where my conduits were before starting.

#53537 06/28/05 09:55 PM
Joined: Apr 2002
Posts: 7,274
Likes: 2
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Sounds like another well planned job, with superior scheduling.

The owner/GC probably found out that the POCO or AHJ 'really' wanted the bollards

John


John
#53538 07/01/05 07:47 PM
Joined: Jan 2003
Posts: 1,429
L
LK Offline
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John, missing bollards seems to be a big problem, it looks like everyone is looking for someone else to put them in, the utility usually gets after them, if they forget.

#53539 07/08/05 11:49 AM
Joined: Dec 2004
Posts: 20
R
Member
Check with your UTILITY - Her on Long Island it is REQUIRED, anything above ground MUST be Sch 80 PVC. NO MATTER WHAT !!!

#53540 07/08/05 12:18 PM
Joined: Jul 2002
Posts: 8,407
Member
I can't go against what has been said.
But, being a PoCo/Utility worker myself, we bury our cables (400/230/11kV and 33kV) in PVC.
We've done it this way for over 30 years like that here and no worries so far.
I've worked with PVC Conduit up to 600mm(2ft) diameter and yes, it can be bent to an offset, if you are careful.
These days they use multiple little ones.
Oh well it was good for the experience I suppose. [Linked Image]
Just my own opinion, I'd never put metal in the ground, that carries live conductors.
In one word, Rust.

#53541 07/08/05 08:31 PM
Joined: Jan 2003
Posts: 4,391
I
Moderator
I agree it can meet the NEC minimums.

I feel like I am on my own here but I will not break the surface exposed with anything less than RMC. Very few of our contracts would allow us to use PVC like that in the first place.

In my area we will have to think about snow removal equipment. A good size snowblower can break frozen PVC easily, particularly if it is held fast by cement or asphalt.


Bob Badger
Construction & Maintenance Electrician
Massachusetts

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