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Rolling Thunder
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Discussion Starter · #1 ·
Ok let me see if I have this right. I'm running (2) 120 volt circuits 375 feet for two gate openers that use 12 amps starting and 8.5 amps running. I will be installing (2) # 4's on 20 amp circuit breakers, and (1) #10 neutral and one #10 ground. All in pvc. This should keep my voltage drop to 2%. Do these calculations look correct. Any comments are appreciated.
 

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What is the load current? Oh never mind, you said it. Let me check my code book and see what I get.

Rough calculation I get you could use something closer to a #6-#8. I'd have to get a pencil and paper to do a solid calc.
 

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Why a reduced neutral when running 2 x 120 volt circuits? I know a reduced neutral is normal when there are mixed 240 volt and 120 volt loads, but should you do it when you are only running 120 volt circuits?
 

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What if only 1 is running? It will need a full size neutral. You could put a SQ D AC disconnect at the first one and swap out the dummy CB for 2 QO120 CB's.
 

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I would run a full size neutral, but I would probably run #8 instead of #4 and put it on a 15A breaker anyway… not that that makes any difference.
 

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I make all the electrons line up for their Flu shots
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Ok let me see if I have this right. I'm running (2) 120 volt circuits 375 feet for two gate openers that use 12 amps starting and 8.5 amps running. I will be installing (2) # 4's on 20 amp circuit breakers, and (1) #10 neutral and one #10 ground. All in pvc. This should keep my voltage drop to 2%. Do these calculations look correct. Any comments are appreciated.

Do what calculations look correct? You posted your results only , not your calcs. Show us how you arrived at those sizes and then we approve or not. I have apps on my computer that do all the work, but those are not my calculations.
 

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Estwing magic
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Ok let me see if I have this right. I'm running (2) 120 volt circuits 375 feet for two gate openers that use 12 amps starting and 8.5 amps running. I will be installing (2) # 4's on 20 amp circuit breakers, and (1) #10 neutral and one #10 ground. All in pvc. This should keep my voltage drop to 2%. Do these calculations look correct. Any comments are appreciated.
The calculation is probably okay but is there any reason you need 2% VD?
 

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Rolling Thunder
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Discussion Starter · #9 ·
Ok I will figure at 3% VD. 120volts, copper, 1 phase, 375 feet, and use the running amps for each at 8.5 amps. I come up with #6 for each hot, a #6 for neutral and #6 for ECG.

Using #6
2x12.9x375x8.5 = 822375/26240 = 3.13 VD
 

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Estwing magic
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Ok I will figure at 3% VD. 120volts, copper, 1 phase, 375 feet, and use the running amps for each at 8.5 amps. I come up with #6 for each hot, a #6 for neutral and #6 for ECG.

Using #6
2x12.9x375x8.5 = 822375/26240 = 3.13 VD
I would aim for 4 to 5% VD and go with Frunk's suggestion.
 

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What's the voltage at the supply end, and what's the dataplate voltage tolerances on the opener? Might not even need to care about voltage drop.
 

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Ok let me see if I have this right. I'm running (2) 120 volt circuits 375 feet for two gate openers that use 12 amps starting and 8.5 amps running. I will be installing (2) # 4's on 20 amp circuit breakers, and (1) #10 neutral and one #10 ground. All in pvc. This should keep my voltage drop to 2%. Do these calculations look correct. Any comments are appreciated.
Your EGC needs to be full sized as well.
 

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Yeah #10 would get you somewhere around a 3% VD.

If I was worried about it, I'd just go #8 so long as it's coming out of the customers pocket and not mine.
 

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I'm still saying check the supply voltage and the dataplates on the equipment. It might not matter a damn. Even if it does, you can often buy a buck-boost cheaper than all the extra copper.
 
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