Conduit for outside electrical mains supply run?

Nov 21, 2004 4 Replies

We are upgrading our service to 200A and have several choices for how to clad the mains supply run from the aerial drop down the side of the house (about 20 feet).



Choices:



  1. Use flexible cable with tough plastic surface
  2. Place wire in PVC conduit
  3. Place wire in metal conduit

What are your recommendations taking into account? a] Paintability, neatness, and overall look b] Durability and minimal need for maintanance c] Relative cost


Local codes prevail in all cases. Here GRC or IMC is required for the mast. If you are in the south pvc will not last very long 4-10 years even when painted. PVC even the sunlight resistant type will not last for a long time exposed to the sun. Seal-tite same answer

GRC most expensive IMC next, neither will ever need maintenance unless there is physical damage. Seal-tite next, subject to physical damage PVC cheapest lest protective. See first statement. LOCAL code prevails. I would use IMC and "for-get-about-it"

although keeping it covered with latex will help.

randy

That is what is used here outside of Chicago, due to codes.

Good reasons, unless you want to maintain or repair it in the future.

Given that the main feed, before your main fuse/breaker, is limited only by the protection on the pole transformer, having the maximum protection seems to me a really good idea.

This is *very* helpful -- I hadn't realized that PVC was so unstable outside.

Would you recommend against it even in the Northeast (Massachusetts)? I mean if you only get 4-10 years in the South, how much longer can you get in the North? While we may get less heat, we still have plenty of sunlight and I can't imagine that the freeze/heat cycling is so good either? Right???

Now what diameter conduit would I typically need for 200A service? I want to use the smallest diameter possible and would be willing to even go copper over aluminum if it allowed me to use a narrower conduit.

Are there some good rules of thumb here for conduit diamter vs. Amperage for Aluminum and for Copper?

Thanks

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