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#115252 - 08/29/03 04:15 PM "Which is better, plastic or Steel?"
Admin Offline

Registered: 10/07/00
Posts: 3417
Loc: NY, USA

About year ago someone started a thread about "Which is better, plastic or Steel?"

I came down squarely on the side of plastic and took some flak for it. My reasons were it does not rust, bust, or collect dust, or it does not deteriate as easily, and was easier fixed if damaged.

Naturally there were those that spoke of the strength of steel. I understand that argument, but my decision stands that I prefer plastic.

Last week, a building engineer at one of our schools was cleaning up behind one of our modular classrooms. When he moved some grass and leaves, he found this pipe. Rigid (not intermediate) that has been in a very long time. The conduit is completely separated, and you can see the conductors. The edges are sharp, and Lord help us in the event of a fault.
We have to schedule an outage to replace it WITH PVC.

The last pic shows the footer washed away under the brick, a non-electrical issue to be sure, but still ugly.

George C.
Tools for Electricians:
#115253 - 08/29/03 04:35 PM Re: "Which is better, plastic or Steel?"
walrus Offline
Registered: 07/25/02
Posts: 680
Loc: Bangor Me. USA
So how long has the install been there and what if joe blow maintenance man hit a plastic riser with a lawn mower and it broke. Would you have to schedule a shut down to repair it right??. I'll take steel.
#115254 - 08/29/03 04:56 PM Re: "Which is better, plastic or Steel?"
iwire Offline
Registered: 01/05/03
Posts: 4391
Loc: North Attleboro, MA USA
I would replace it with steel, this is just my personal opinion.

I use plastic exclusively underground but I always break the surface with steel.

How long did it take to rust out like this?

We have no way of knowing if plastic would have lasted as long, for all we know that steel may have taken many hits with a lawn tractor and remained undamaged.

Service conductors in exposed plastic raceways scare me.

JMO, Bob

As a side note if I was getting this shut, down the disconnect and the trough look in tough shape too.

Why is one disconnect rustier than the other, they look identical (other than rust)????
Bob Badger
Construction & Maintenance Electrician
#115255 - 08/29/03 05:59 PM Re: "Which is better, plastic or Steel?"
Nick Offline
Registered: 08/13/01
Posts: 599
Loc: Riverside, CA
The Ultimate in strength and corrosion protection!
#115256 - 08/30/03 07:10 PM Re: "Which is better, plastic or Steel?"
PCBelarge Offline
Registered: 06/08/03
Posts: 681
Loc: Dobbs Ferry, NY, USA
I myself like both PVC and Rigid, they both have their special uses.
What I would really like to see (but know it is unrealistic) is more preventative maintenance.
BTW - great pictures!

Pierre Belarge
#115257 - 08/30/03 08:15 PM Re: "Which is better, plastic or Steel?"
Bjarney Offline
Registered: 04/10/02
Posts: 2527
Loc: West-Southern Inner-Northeast ...
For galvanized-rigid conduit, the points of transition from soil to air, concrete to soil or air to concrete are said to be most susceptible to corrosion.

I don't know of a reference to back this comment.
#115258 - 08/31/03 01:45 PM Re: "Which is better, plastic or Steel?"
iwire Offline
Registered: 01/05/03
Posts: 4391
Loc: North Attleboro, MA USA
Scott, I think your back up to that statement could be a look at any wood or steel pilings in water, they always rot out at the transition from water to air, both are need for decomposition.

Nick, we use that conduit or a type like it, on many jobs and you make a good point, one 10' stick of this would "fix" this service for a long time.

Bob Badger
Construction & Maintenance Electrician
#115259 - 09/18/03 07:52 AM Re: "Which is better, plastic or Steel?"
Zapped Offline
Registered: 10/01/02
Posts: 482
Loc: Huntington Beach, CA, USA
I have to agree with PCBelarge...each has it's own advantage and each has serious disadvantages. I prefer PVC underground, transitioning to metal a couple of inches above grade. This way, the only PVC exposed is usually the coupler, which is naturally thicker plastic and stronger. Metal, especially right near the ocean where most of my work is, WILL disolve eventually if in contact with the soil. You can bet on it.

I recently had an association community with pole lights fed from galv rigid that had corroded and collapsed UNDER ROADS in the community. We had to abandon those runs and route power from other sources, add pilasters, cut through 4" thick roots, etc.. My arms are still sore from all the trenching (in the middle of August, I might add)!
#115260 - 09/18/03 08:38 PM Re: "Which is better, plastic or Steel?"
u2slow Offline
Registered: 09/18/03
Posts: 200
Loc: Salt Spring, BC, Canada
Supposing PVC was used underground and transitioned to rigid or EMT a few inches above grade... how about pouring a concrete curb around it?
#115261 - 09/20/03 03:19 PM Re: "Which is better, plastic or Steel?"
sparky Offline
Registered: 10/18/00
Posts: 5303

peanutbutter in my chocolate, chocolate in my peantbutter?

2 thumbs up Nick......

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