370 foot run to a 200 amp panel underground? - Electrician Talk - Professional Electrical Contractors Forum
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Old 06-06-2019, 02:10 AM   #1
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Default 370 foot run to a 200 amp panel underground?

Im working on running about 160 feet of 3" conduit to a pull box, then unfortunateley the previous owner already ran a 2" another 220' to where a panel will go. Im supposed to fish tape that pipe or vacuum. Fun stuff...My voltage drop is around 9% leaving 236 volts at end of run/panel feeding small cottage and garage. Any thoughts? I was wanting to use 4/0 but dont know if Id get it through the 2"
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Old 06-06-2019, 06:35 AM   #2
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How are you doing that voltage drop calculation? That doesn't add up, 236v is not 9% drop from 240.

Do you think the old conduit's all in good shape? You might as well check that before you buy materials.

Would adding a handhole anywhere help?

If it's not an easy pull, the copper cost may be worth it.
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Old 06-06-2019, 09:17 AM   #3
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4/0 in 2 inch isn't to bad if someone is pushing at the other end and a bit of lube.


Tim.
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Old 06-06-2019, 09:20 AM   #4
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Voltage drop is entirely dependent on the load.

If the 200 amp panel only peaks at 80 amps of load, you will certainly have less voltage drop.

So what is the calculated load on the panel?

When there is money in the project or the customer requests it sized for the full bore panel rating, we do the voltage drop calcs at the full panel ampacity.

However, instances such as this or where it's just not needed, we do our voltage drop calcs at the calculated load rather than the panel rating. It's not uncommon to be done this way.
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Old 06-06-2019, 11:27 AM   #5
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How are you doing that voltage drop calculation? That doesn't add up, 236v is not 9% drop from 240.

Do you think the old conduit's all in good shape? You might as well check that before you buy materials.

Would adding a handhole anywhere help?

If it's not an easy pull, the copper cost may be worth it.
Its 236 at the starting point, where the meter is. Yes your right, Im probably going to try to put my fish tape in, but the conduit ends short of where its supposed to and is buried, so the homeowner has a backhoe, he needs to dig it out first. Thanks for the responce!
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Old 06-06-2019, 12:19 PM   #6
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4/0 in 2 inch isn't to bad if someone is pushing at the other end and a bit of lube.


Tim.
Not too bad, if the conduit's in perfect shape, slippery wire, plenty of lube, and not too much bend, and if possible downhill.
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Old 06-06-2019, 12:21 PM   #7
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Its 236 at the starting point, where the meter is. Yes your right, Im probably going to try to put my fish tape in, but the conduit ends short of where its supposed to and is buried, so the homeowner has a backhoe, he needs to dig it out first. Thanks for the responce!

I would put something more than a fish tape in to see if it's partially collapsed at all.



Actually if the homeowner has a backhoe that solves a lot of problems.
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Old 06-06-2019, 07:32 PM   #8
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Originally Posted by Cow View Post
Voltage drop is entirely dependent on the load.

If the 200 amp panel only peaks at 80 amps of load, you will certainly have less voltage drop.

So what is the calculated load on the panel?

When there is money in the project or the customer requests it sized for the full bore panel rating, we do the voltage drop calcs at the full panel ampacity.

However, instances such as this or where it's just not needed, we do our voltage drop calcs at the calculated load rather than the panel rating. It's not uncommon to be done this way.
Actually they dont know their load, just want some basic plugs and switches, no kitchen, etc. However in Trinity County Ca, some people like to put a zillion grown lights in, and dont want everyone to know what their doing, so Im planning on full load, or 80% of 200...
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Old 06-06-2019, 11:55 PM   #9
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I would put something more than a fish tape in to see if it's partially collapsed at all.



Actually if the homeowner has a backhoe that solves a lot of problems.
Thanks, I know what you mean, could be collapsed...He might have to dig alot of it up if that happens, but he has a big CAT backhoe...Thanks for the responce..
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