Irrigation pump in lake

D

dekeSC

Owner
Location
South Carolina
Occupation
Electrical Contractor
I am tasked with wiring a 120v irrigation pump for a residential customer. A circuit was previously pulled from the house panel and stubbed out near where the conduit and wiring will be install down to the lake. That circuit is a 12-2 romex, knowing or at least assuming the pump would need to be GFI protected I let the homeowner know that this would work. Today I was informed that the pump will need to be 240v, don't know why but it does. My question is will a 2 pole GFI circuit breaker work correctly without a neutral? Or any suggestions?
 
I remanned a failed pump for something similar and would not install it, fed by old ratty 2 wire NM underground from old service. They were intending on selling and didnt want to upgrade.
 
dekeSC said:
I am tasked with wiring a 120v irrigation pump for a residential customer. A circuit was previously pulled from the house panel and stubbed out near where the conduit and wiring will be install down to the lake. That circuit is a 12-2 romex, knowing or at least assuming the pump would need to be GFI protected I let the homeowner know that this would work. Today I was informed that the pump will need to be 240v, don't know why but it does. My question is will a 2 pole GFI circuit breaker work correctly without a neutral? Or any suggestions?
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If that 12-2 NM (Romex) is run outdoors, that is not permitted, conduit or not.
To your question about the GFCI, yes it will work. You don't need a load neutral, just neutral from GFCI to neutral bar.
 
AFAIK, outside of things like types S/W/R cables, the un-insulated grounding conductor isn't counted, so 12/2 NM is two 12g insulated wires and a 12g bare wire, all inside one jacket. At least "I've always done it that way" :cool: .

To me "romex" is kind of vague - it could be NM (wrong), or it could be UF (suitable).
 
zbang said:
AFAIK, outside of things like types S/W/R cables, the un-insulated grounding conductor isn't counted, so 12/2 NM is two 12g insulated wires and a 12g bare wire, all inside one jacket. At least "I've always done it that way" :cool: .

To me "romex" is kind of vague - it could be NM (wrong), or it could be UF (suitable).
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Maybe you're to young to remember when both were available and we had to specify.
 
ptonsparky said:
Maybe you're to young to remember when both were available and we had to specify.
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Since the OP mentioned the circuit was pulled and stubbed out. I highly doubt is was run 60 years ago, since that's about when the ground was added to the NM. So the mention of 12-2 most certainly means 12-2 with ground.
 
I guess I should have been more clear. Someone prior to myself had installed a 12-2 non metallic sheathed cable (one black, one white and a bare ground) from the house panel to a junction box on the outside wall of the house. I will be extending that in a trench approximately 150' in length and 20" deep with 3/4" pvc conduit. I plan to pull #10 thhn stranded conductors to a weatherproof junction box mounted on a 4x4 pressure treated wood post. I'm not 100% sure of the actual requirements for the pump yet, but my main concern was if a 2 pole GFI circuit breaker would function correctly without the neutral conductor available? Because I will only have two hot conductors and a ground available.
Thank you for all your support. I am a one man shop so I have no one available to bounce these questions off of.
 
dekeSC said:
I guess I should have been more clear. Someone prior to myself had installed a 12-2 non metallic sheathed cable (one black, one white and a bare ground) from the house panel to a junction box on the outside wall of the house. I will be extending that in a trench approximately 150' in length and 20" deep with 3/4" pvc conduit. I plan to pull #10 thhn stranded conductors to a weatherproof junction box mounted on a 4x4 pressure treated wood post. I'm not 100% sure of the actual requirements for the pump yet, but my main concern was if a 2 pole GFI circuit breaker would function correctly without the neutral conductor available? Because I will only have two hot conductors and a ground available.
Thank you for all your support. I am a one man shop so I have no one available to bounce these questions off of.
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In this case, the NM is allowed since it terminates just on the outside in an enclosure. As to the GFCI, they don't usually do well on runs that long. There will be a lot of nuisance tripping. It's better to put them at the load end. A small panel at the load, and a GFCI breaker there. Since you only have 12-2 to work with, you would need to run a 12-3 so you could send a neutral to the panel. The load itself doesn't need the neutral, but the GFCI does to power the electronics in it.
So you either take a chance on the GFCI holding, or run new feeder cable with a neutral to the subpanel at the load end.
 
I agree with Bill about the distance being a possible problem.
 
is 100 all that long. I mean its getting there but I have gfci on 250 ft of 12 too. Millions are ran on long circuits and a great way to add to fault protection where V drop might be a concern. I had a gfci trip on a borrowed machine a while back and didnt feel like fooling with it. Tripped 2 different ones and plugged direct. That is the only "nuisance trip I can even recent in recent decades.
 
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When I was 20 I was all about v drop (only thing I knew) and thought 50 ft was a long circuit. Now that I am in mid 60s and ran and used 1000 circuits I found about 150 ft where things start getting fuzzier for loaded circuits. Compressors, small welders. Saws not so bad as they can get to speed before loading and have operator on them.
 
Nuisance tripping as a concern wouldnt even crossed my mind until it actually happened. If this is a small motor,,, and you have 10 it wont even recognize it aint sitting at the service.
 
You will be fine... The speculation on the net can be endless. Not saying it doesnt happen,,,, just saying I have done this for decades, more than once and never seemed to be an issue and if something tripped it t 100 would at 10 ft too.
 
Sberry said:
When I was 20 I was all about v drop (only thing I knew) and thought 50 ft was a long circuit. Now that I am in mid 60s and ran and used 1000 circuits I found about 150 ft where things start getting fuzzier for loaded circuits. Compressors, small welders. Saws not so bad as they can get to speed before loading and have operator on them.
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Voltage drop is not the real reason, it's more to do with leakage, it doesn't take a lot to reach .006ma
 
I understand that,,, was merely making it a point we have used it on long circuits, the protection is a hedge against drop.
 
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