Electrical help needed

[Pooh_Bear]

I thought about doubling up on the cable run.
Just buy a 1000 ft roll of 10-2 with ground.
Run 500 feet and use all 3 wires for one hot side,
and run the same for the other hot side.
Drive a ground rod at the pump site and bond on to it.

The calculations seem to bear it out.

# 6 AWG wire has a diameter of .162
Which gives a cross sectional area of .0206

# 10 AWG wire has a diameter of .1019
Which gives a cross sectional area of .0082

So using all 3 wires in 10-2 w/grnd romex,
I get a total cross sectional area of .02445
Which is close to being a #5 AWG size, .02957 CSA

AWG size tables. http://www.powerstream.com/Wire_Size.htm

Don't think the NEC would allow this.
But I'm not subject to inspection.
Not to worry. A 1000 foot roll of 10-2 is out of my price range.

Pooh Bear

 

[Bill_C]

Actually, it's better to mix the phases up on each multi-conductor. In other words, run one 10-2 with ground as you normally would. Then run the second 10-2 with ground, connecting each leg from that wire in parallel with the other 10-2. It's more work but there's physics behind this....

 

[Pooh_Bear]

OK, I gotta know. What's the physics behind it.
I was a math major in college and had a lot of physics.
Thought about switching majors.

I'm sure I'll understand it. Please explain it to me.

Pooh Bear

 

[_RaT_]

I have a sump pump. According to the plate on the motor it is 230v and 9 amps.
I'm trying to find the smallest wire I can use to power it.
I'm using this site to do my calculations.
http://www.powerstream.com/Wire_Size.htm

Scroll down near the bottom to get the online calculator.

I picked copper wire. 240v single phase. length=500 feet. Amps=9
According to that, looks like I can use 10 AWG wire. Is that right.
I asked on a forum of electricians and they said 4awg or at the most 6awg.
10 awg is out of my budget. Forget 4 and 6.
I mite could scrounge up enough 10-2 romex. Mite have to do some splicing.

This is my sump pump. The model 4290. Got it for $20 out of the classifieds.
http://www.zoeller.com/zcopump/products/agricultural/agricultural.htm

What do y'all say. can it be done somehow.

Thanks.

Pooh Bear

#10 copper 500 foot paired run with a 9 amp load will drop the voltage from 240V to 230V or a little over 5% voltage drop. I would be OK with that on something like the pump you showed. #8 copper obviously would be ideal, but copper is a fortune. Put the wire(s) in a 1" PVC conduit and remember to run a ground wire as well, #12 will be sufficient since the breaker need not exceed 20A/240V. Pull individual wires, its simple. Keep the bends to a minimum and flex the conduit as much as possible instead of buying prebent 90's or 45's. You get 360 degrees of bend (flex of conduit does not count as a bend) before you need a J box or LB (little box with oval cover) to pull from. When done, turn on the pump and verify the voltage when the pump is under load.

 

[Inspector507]

Don't think the NEC would allow this.
But I'm not subject to inspection.

Pooh Bear

You're right it won't. Paralleled #10 not allowed, driving a rod to "make" a ground not allowed and dangerous. Using all 3 wires together in one cable for one hot conductor not allowed........

 

[Bill_C]

OK, I gotta know. What's the physics behind it.
I was a math major in college and had a lot of physics.
Thought about switching majors.

I'm sure I'll understand it. Please explain it to me.

Pooh Bear

My specialty isn't electrical power transmission design, but I was told many years about why it wasn't allowed by Code...magnetic flux from self-inductance? My memory ain't very good and I've forgotten the particulars. Coincidentally, Friday at work a couple of guys around me were talking about an installation where somebody put parallel conductors together (three conductors of one phase together in one conduit, three conductors of second phase in a conduit, three of the third phase in a conduit) and they couldn't believe a licensed contractor would do that (and the contractor didn't know it didn't meet Code). They also were kinda surprised the conduit held up to the forces that were generated.....

 

[ccsial]

If you could scrounge up some control transformers, 220 to 440 you could run 440 and the amps would be 1/2 of the amps at 220. That's what I did for my 1400 foot run to my cabin. I went with 120/440. You need about a 1 KVA transformer for your pump. The transformers may even be cheaper than the wire.

 

[_RaT_]

#10 copper 500 foot paired run with a 9 amp load will drop the voltage from 240V to 230V or a little over 5% voltage drop. I would be OK with that on something like the pump you showed. #8 copper obviously would be ideal, but copper is a fortune. Put the wire(s) in a 1" PVC conduit and remember to run a ground wire as well, #12 will be sufficient since the breaker need not exceed 20A/240V. Pull individual wires, its simple. Keep the bends to a minimum and flex the conduit as much as possible instead of buying prebent 90's or 45's. You get 360 degrees of bend (flex of conduit does not count as a bend) before you need a J box or LB (little box with oval cover) to pull from. When done, turn on the pump and verify the voltage when the pump is under load.

Wow, this new software has me all screwed up. I thought there was but one post to your question. Unknown to me were the almost 3 pages of replys. Get #8, put it in conduit of just forgo the project, it's really that simple. Add a neutral and have 120V there for lighting etc. A 1" PVC conduit will handle two #8's, a #12 ground and a #10 or #12 neutral. Doing parallel runs is just not worth it until you are up into the high current distribution panels. At that point you typically go to aluminum, you cannot get it at Home Depot and you cannot pull it without a lot of effort.

 

[Pooh_Bear]

I stopped yesterday in Home Depot to check prices.
#6 stranded wire was 87cents per foot.
I would need 1000 feet of it. Plus conduit.
I'll buy a generator before I'll spend that much on wire.

Pooh Bear

 

[Lindblom Lawn Care]

Buy an old fire truck (pumper) with suction hose and length of fire hose. An old pumper will move 500 to 1000 gallons a minute and you would have another toy Granted you wouldn't want to get to close to the river bank with it.