Russel's thread about schedule 80 PVC got me thinking about this.

UL and the NEC consider schedule 80 PVC in the same class as RMC as far as damage resistance?

UL says

I can not imagine running a PVC up a street pole. Beside the fact that our local POCO would not accept it, all it will take is one small bump from a car to break any PVC.

Is running PVC exposed to physical damage common in other areas?

Could I come up out of a slab with schedule 80 PVC at a loading dock and satisfy the NEC?

Sometimes I wish we could get schedule 120 RMC for some locations.

Bob

My thinking is that common sense should be used.

If it can get hit with a car,truck,or tractor,I like rmc. Sometimes a residential service will wind up on the drive-in end of the garage. I always use rmc on these for the stubdown on an ug service,pricey,but then if a car hits it,I've done all I can do.

Russell

Bob, I lost a job a few years ago by suggesting the use of rigid pipe on the ug in front of a garage, the owner told me i was a jack a$$, the other EC told him there was nothing wrong with using PVC, and that i was an old time electrician that din't know any other way of doing the job.
This past march his wife came home from the local lemon aid stand at 2:00AM and drove into the PVC, his neighbor told me they heard a loud thud, and there was a bright flash, and then, they lost power.
Bob, i suggested not only using rigid, but also installing a curb or post.

If a car runs into RMC and the surface behind is solid(like a pole) theres a good chance the RMC is squished. With PVC its definetely broken. In the winter up here you could kick PVC and have it break when its really cold.

The power company runs PVC down their poles for underground services around here.

The reality is that one cannot prevent accidents, and keeping damage from something like cars and trucks will take more than RMC.
GA.Sparky said it right, common sense generally prevails - when there is common sense .

Pierre

I just can not agree schedule 80 PVC provides even remotely the protection of RMC 40 or 80.

It will take a very substantial hit from one of todays plastic and rubber bumpered cars to damage RMC.

On the other side I agree with walrus,


I will stick with RMC where motorized vehicles can drive.

Russel's use of PVC at a deck seems like a perfect place for PVC.

So what the NEC is saying is that no matter the lack of common sense by the installer the inspector can not force the use of steel raceway in any area.

Job security.

Bob

Another option is to cover the section of PVC subject to damage with steel "U" guard. I always recommend this on pole risers and sometimes the utility will comply. This can be a less expensive and easier to install alternative to RMC but unfortunately supply houses do not carry the stuff.

-Hal

We wired a combination tractor shed/workshop on a farm a few years ago. We used Rmc for the stub down for the ug service. Last year,the owner whacked the rigid pretty good with a bush hog as he was turning the tractor. It dented the rigid,but no real harm. I believe it would have been bad news with even shed 80 pvc.

Russell

The deck area would most likley give the PVC additional protection, however, in a driveway area PVC or RMC should have additional protection, as Hal, noted the installation of a gutter, if you can find one is good. I like to use a guard post or curb in front of the pipe, yes this does increase the cost of the job, but at least suggest the additional protection, and let them refuse it.
Most of the time, we forget to look at other hazards that may exist.

I have seen Schedule 80 used extensively around coastal areas because the rigid/IMC rusts so bad. Areas where chemicals like chlorine or acids are used also seem to need the PVC over the metal so I guess it would also depend on the environment even if there are hazards of being hit by vehicles etc.

In areas where you must use PVC, such as the costal areas, which we have a lot of here in Jersey, we will add protection if needed.
And here in Jersey the Utility and EC's use PVC on the poles.

Bob:
FYI, our utilities also condone PVC for PRIMARY risers at poles, (going to UG, to pad mount xfrs) 4160/7KV & 13.5KV

Yes, PVC is used widely for 120/208 and 277/480 risers at poles. The utilities require that the risers be on "the quarter of the pole away from the flow of traffic", or some wording to that effect.

That should make your day

John

John.

It just scares me to think of 13 KV only protected by plastic.

Some of the utilities now make us use 4" or 5" RMC large radius sweeps with 10' of RMC on either side of that. 10' up the pole, sweep and 10' underground then we change to PVC

That said it also scares me that many times these RMCs are not bonded to anything. We will provide the POCO specified bonding fitting on the top of the RMC but it often goes unconnected.

Have you ever tried to move 20' and a large radius sweep in 5" RMC. Glad we rent all terrain fork lifts.

Delectric's post made me think about the times I've been on vacation on the SC and NC coasts.

I've never noticed any Rmc there,unless it's a riser on an OH service.

Disconnects,and other metal electrical parts quickly corrode away there,and you can see installations only a couple years old rotting off the wall.

Russell

Russell,
There's a panel I installed for a house in San Diego... Literally "on the beach", I've gone back there for additional work on numerous occasions, & every time, I put a new coat of noalox on the bus bars... Thing started showing corrosion about 6 months after install!.. So far so good though! (Corrosion was the reason for replacement in the first place!).. If you want to see EMT after its been at the beach here for a while...
click here
& scroll down to the 5th pic...

-Randy

Boy that is "disapearing emt"