What would you do?

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AZsparky

AZsparky

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Scottsdale, AZ
Have to set a new underground fed 100 amp rated 240 volt sub panel 170' away from main service. Total load at sub panel will be a (used once in a while) 50 amp RV receptacle, a 4 amp load for a small 120 volt "bunny den" AC unit, a small 4 amp under counter refrigerator for a BBQ Island and then several convenience receptacles for the BBQ Island and a ceiling fan for a new pagoda. I figure a #4 CU 70 amp feeder in an 1-1/4" PVC conduit will still be fine, but am a bit concerned about voltage drop. Don't want to have to pull #2's. I have not measured incoming voltage in at the service entrance (400 amp service) Any thoughts on conduit and feeder size? TIA.
 
AZsparky said:
Have to set a new underground fed 100 amp rated 240 volt sub panel 170' away from main service. Total load at sub panel will be a (used once in a while) 50 amp RV receptacle, a 4 amp load for a small 120 volt "bunny den" AC unit, a small 4 amp under counter refrigerator for a BBQ Island and then several convenience receptacles for the BBQ Island and a ceiling fan for a new pagoda. I figure a #4 CU 70 amp feeder in an 1-1/4" PVC conduit will still be fine, but am a bit concerned about voltage drop. Don't want to have to pull #2's. I have not measured incoming voltage in at the service entrance (400 amp service) Any thoughts on conduit and feeder size? TIA.
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'm kay... it won't be code compliant. that's a given.
what's killing you, is the 120 volt loads. you are going
half a football field.

what's really killing you is the location. you live where
people refrigerate their pool water during the summer.
air conditioning and refers aren't nice to have, they are
something that runs 24/7.

that 50 amp RV plug, when plugged in, WILL have the
AC running. the voltage drop will kill the little AC unit
that is chilling the bunnies. the bunnies will have heat
stroke. the little refrigerator will not like the voltage
drop either, and you'll end up with dead rabbits and
warm beer. you have three chiller loads cycling on
the end of a long line.

run a 220 volt line out there, put a little single phase
transformer to give you 120 volts for the incidental
loads.

even then, 50 amps at 240 volts going 170', will give
you 2.26% voltage drop, using #2 aluminum. copper,
quite honestly, is a waste of money.

i'd use 3 #2's in 1 1/2" pipe, with a #10 copper ground.
but you could direct burial UF cable. save some money.
you only need a 1 1/4" pipe, but it's a long run...... i'd measure
the run with a mule tape, and see if you can get three
wires out of a 500' spool..... it'll be close....
 
Yeah, what they said. Buy that 4 conductor mobile home feeder quadplex in #2 AL. It's dirt cheap, phase identified, and ready to go.
 
Thanks

Thanks

Thanks to everyone for the money saving idea. But, never worked with an AL feeder. Is the 2-2-24 AL rated to be run in conduit, and if so, how hard is it to pull into a PVC conduit. Probably be right at 360 degrees of bends. Seems like the weight would be nothing next to the copper conductors I usually pull. It's going under a lot of new hardscape and pavers, so I need the feeder to be in conduit. TIA for your opinions.
 
AZsparky said:
Thanks to everyone for the money saving idea. But, never worked with an AL feeder. Is the 2-2-24 AL rated to be run in conduit, and if so, how hard is it to pull into a PVC conduit. Probably be right at 360 degrees of bends. Seems like the weight would be nothing next to the copper conductors I usually pull. It's going under a lot of new hardscape and pavers, so I need the feeder to be in conduit. TIA for your opinions.
Click to expand...

If it would happen to have THHN/THWN insulation it should pull about same other then overall lighter weight, but a lot of aluminum conductor usually has RHW or XHHW insulation and those typically seem to pull harder then THHN/THWN - make sure you use pulling lubricant and try to eliminate unneeded elbows as much as possible.
 
AZsparky said:
Thanks to everyone for the money saving idea. But, never worked with an AL feeder. Is the 2-2-24 AL rated to be run in conduit, and if so, how hard is it to pull into a PVC conduit. Probably be right at 360 degrees of bends. Seems like the weight would be nothing next to the copper conductors I usually pull. It's going under a lot of new hardscape and pavers, so I need the feeder to be in conduit. TIA for your opinions.
Click to expand...
It is direct bury rated, but it pulls in coduit just fine. I would use it without hesitation.

1 1/4" pvc, never had a problem.
 
Last edited:
AZsparky said:
how hard is it to pull into a PVC conduit. Probably be right at 360 degrees of bends.
Click to expand...
PVC conduit is cheap compared to the costs of wire, trenching, and labor. Upsize your conduit and use the longest sweeps possible. At 360 deg of bends, I'd strongly consider putting a pull box in at some midpoint location.

Before installing wire, pull a flexible rubber mandrel through the conduit to clean out any debris that might have gotten in during construction, then dump a bunch of lube in the conduit and pull a swab or rag through to spread it along the length. Also lube the wires as they enter the conduit. Don't just tie the mule tape to the wire head; use a swivel connection. Pull slow and easy and have men actively feeding the wire in. The mule tape can cut into the walls of PVC sweeps if too much speed and/or pressure is applied.

And as stated earlier, expect power demands on that circuit to grow over time. Size accordingly.
 
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