Cool and rainy, stuck at home taping and floating ceiling when all of a sudden...

Keith_J

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Power outage! Dang, I will have to use the MMEP 002A. The double M is for more as it is self propelled[thumbzup]. But still, 75 yards to the shop in the torrential downpour, motoring it 200 yards around the house to the service entrance point, then manual hook up...there has to be a better way.

Fortunately, it was a brief outage but there has to be a better way. I know remote start is an option but how about 150 yards of service entrance wire to the shop? Voltage drop over 3C #8 SE for that length? Or should I go with #4 aluminum SE? The cost is about the same for either, I would think the AL would have less voltage drop.

This will be all manual reconnection with safety interlock. The 002A is run once a week, load tested monthly. Old PMCS habits die hard.
 

PeterD

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If it is a permanent installation, mobile home feeder may be an option. You can direct bury it, which you can't with SE.
 

NDT

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Can you figure out a compliant method to use your shop power feed to reverse feed your main panel?
 

doghead

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Hate to sound like the grammar police but, MEP = Mobile Electric Power.

No need for the second M.
 
NO NO NO ....

SMEPP - Self Mobile Electric Power Plant

or

The new trend in the military is an acronym of acronyms, so MM 002A would work: Mobile Mobile Electric Power.

Yeah, that's the ticket, it even has redundancy. We know the guberment loves that.
 

PeterD

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Can you figure out a compliant method to use your shop power feed to reverse feed your main panel?
I was an EE in a prior life. I spent a lot of time on this problem a few years ago when someone online kept trying to back-feed from their detached shop.

Though I did come up with a way that might work, it is impossible to create a system that meets the legal (code) requirements without enormous expense for custom equipment. The cost of a second cable was a small amount compared! MH feed is about $1 a foot, so a 100 ft run is trivial cost wise.
 

DieselAddict

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I was an EE in a prior life. I spent a lot of time on this problem a few years ago when someone online kept trying to back-feed from their detached shop.

Though I did come up with a way that might work, it is impossible to create a system that meets the legal (code) requirements without enormous expense for custom equipment. The cost of a second cable was a small amount compared! MH feed is about $1 a foot, so a 100 ft run is trivial cost wise.
+1 on mobile home cable. That will be the low cost option.

A reverse power relay interlocked to the main breaker on the panel should do it. Assuming you could get the local utility and inspector to sign off on it since it would be an unusual setup for a residential environment. BUT as you rightly point out running 100' of cable for the generator would have been easier and cheaper. ;)

To the OP - I wouldn't go less than #4 aluminum for that length. If you were considering a larger generator in the future I would put in #2. That should keep your voltage drops below a few percent. Your AC compressor will thank you.
 

PeterD

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It gets complicated. You need a transfer contactor with a low voltage coil at the house (the utility feed transfer) and that transfer contactor has to have (built in, not simulated with another relay) a contact that goes back to the gen set's contactor. The gen set then can't apply power until it is able to confirm that the main transfer contactor has in fact thrown isolating the utility from the local system.

So you end up with two contactors (one in the remote generator site and one at the utility connection (main panel)) and at least two pairs of low voltage communications between the two. I could draw it up if anyone wants it, but it is complex, requires some expensive parts and as we've agreed: there are much better and cheaper solutions!

I watched a guy who was not a good EE (not an EE at all, he just thought he knew what he was doing...) go to great lengths to try to do it another way. He'd draw some Rube Goldburg setup up and I'd explain how and why it would not work.
 

NDT

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I was an EE in a prior life. I spent a lot of time on this problem a few years ago when someone online kept trying to back-feed from their detached shop.

Though I did come up with a way that might work, it is impossible to create a system that meets the legal (code) requirements without enormous expense for custom equipment. The cost of a second cable was a small amount compared! MH feed is about $1 a foot, so a 100 ft run is trivial cost wise.
Thanks. I tried to make this work but the designs always resulted in a utility back feed possibility, so I ripped out the wiring. I ended up with a system where the cable between my main panel and shop has to be manually transferred from the lugs on the main panel breaker to the lugs on the transfer switch. A pain, but the outages we have here on the Gulf Coast are hurricane related and last for days, so it is manageable.
 
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