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?
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.
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--
"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).]
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.
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. Just my own opinion, I'd never put metal in the ground, that carries live conductors. In one word, Rust.