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#40013 07/10/04 08:11 PM
Joined: Jan 2003
Posts: 4,391
I
iwire Offline OP
Moderator
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
Quote
The marking ‘‘Schedule 80 PVC’’ identifies conduit suitable for use where exposed to physical damage and for installation on poles in accordance with the NEC.

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. [Linked Image]

Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts
#40014 07/10/04 09:15 PM
Joined: Nov 2002
Posts: 558
G
Member
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

#40015 07/10/04 11:58 PM
Joined: Jan 2003
Posts: 1,429
L
LK Offline
Member
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.

#40016 07/11/04 06:24 AM
Joined: Jul 2002
Posts: 680
W
Member
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.

#40017 07/11/04 09:12 AM
Joined: Feb 2002
Posts: 375
G
Member
The power company runs PVC down their poles for underground services around here.

#40018 07/11/04 09:30 AM
Joined: Jun 2003
Posts: 681
P
Member
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 [Linked Image].

Pierre


Pierre Belarge
#40019 07/11/04 09:47 AM
Joined: Jan 2003
Posts: 4,391
I
iwire Offline OP
Moderator
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,

Quote
In the winter up here you could kick PVC and have it break when its really cold

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. [Linked Image]

Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts
#40020 07/11/04 10:24 AM
Joined: Dec 2003
Posts: 886
H
Member
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

#40021 07/11/04 10:29 AM
Joined: Nov 2002
Posts: 558
G
Member
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

#40022 07/11/04 01:42 PM
Joined: Jan 2003
Posts: 1,429
L
LK Offline
Member
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.

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