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pulling large wire through PVC

G

Guest

Jan 1, 1970
0
I need to pull 3 lengths of 2/0 copper THHN through about 270 ft of 2 inch
PVC conduit with two 90 and two 45 bends in it. I've done this before, but
always with three separate lengths of wire pulled together. My supplier
says they may be able to get triplex wire cheaper than three separate wires.
Is the triplex going to be harder, easier or about the same effort to pull
as three separate wires pulled together?

How feasible would it be to pull 3 lengths of 4/0 aluminium wire through
this conduit? It's code-legal, but is it doable? Three 2/0 wires is the
biggest load I've tried through this length of 2 inch PVC, and that was
hard.

I was talking with an electrician friend recently, and he mentioned that
heavy pulling with nylon or poly rope can saw through bends of PVC conduit.
I've always used nylon or polyester rope with no problems. My friend
recommends cotton rope. Is this worth doing? Cotton is a lot weaker than
nylon or polyester, which is a worry, plus I'd have to go buy it.

Mike
 
D

Dean Hoffman

Jan 1, 1970
0
I need to pull 3 lengths of 2/0 copper THHN through about 270 ft of 2 inch
PVC conduit with two 90 and two 45 bends in it. I've done this before, but
always with three separate lengths of wire pulled together. My supplier
says they may be able to get triplex wire cheaper than three separate wires.
Is the triplex going to be harder, easier or about the same effort to pull
as three separate wires pulled together?

How feasible would it be to pull 3 lengths of 4/0 aluminium wire through
this conduit? It's code-legal, but is it doable? Three 2/0 wires is the
biggest load I've tried through this length of 2 inch PVC, and that was
hard.

I was talking with an electrician friend recently, and he mentioned that
heavy pulling with nylon or poly rope can saw through bends of PVC conduit.
I've always used nylon or polyester rope with no problems. My friend
recommends cotton rope. Is this worth doing? Cotton is a lot weaker than
nylon or polyester, which is a worry, plus I'd have to go buy it.

Mike
I guess some people use steel elbows for this. A code class
instructor mentioned that the steel had to be grounded at one time even
if it was underground. Someone got electrocuted while doing repair
work because the steel elbow wasn't grounded. Code writers not familiar
with the history of the requirement later deleted the grounding provision.

Dean
 
B

bud--

Jan 1, 1970
0
Dean said:
I guess some people use steel elbows for this. A code class
instructor mentioned that the steel had to be grounded at one time even
if it was underground. Someone got electrocuted while doing repair
work because the steel elbow wasn't grounded. Code writers not familiar
with the history of the requirement later deleted the grounding provision.

Dean

I believe metal elbows in a PVC run have to be grounded unless buried
below 18 inches, or a concrete requirement for non-service wires (NEC
250.80-ex, 250.86-ex3).

Damaging effect of the rope should depend partly on the rope diameter.
Soft nylon is probably less abrasive than polyester.

I wonder about the effect on triplex pulling it around a bend. The path
around the outside of the bend is longer and the wires can't easily slip
past each other to adjust. And with separate wires the 'longer' wire
tends to stay the same wire.

If you need more answers than you get on this newsgroup you could try
posting on alt.home.repair which has several electricians.
 
On Wed, 16 Jan 2008 19:29:55 GMT [email protected] wrote:

| I need to pull 3 lengths of 2/0 copper THHN through about 270 ft of 2 inch
| PVC conduit with two 90 and two 45 bends in it. I've done this before, but
| always with three separate lengths of wire pulled together. My supplier
| says they may be able to get triplex wire cheaper than three separate wires.
| Is the triplex going to be harder, easier or about the same effort to pull
| as three separate wires pulled together?

My guess is the triplex will be slightly easier because you will not
have as many points where separate wires are contacting the edges.
When the triplex is rubbing on one side of the inside of the conduit,
it is pulling the other wires with it and they will thus not rub on
the other side at that point. OTOH, triplex may not as easily like
to bend going around those conduit bends.

BTW, what is the radius of the four bends?
 
G

Guest

Jan 1, 1970
0
Thanks for all the replies. Particularly for info on jam ratios and mule
tape. I'll either use 3 2/0 copper wires, 2/0 copper triplex, or 4/0
aluminum triplex (hope to avoid the latter, but $ may dictate it), and pull
with mule tape.

Mike
 
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