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Grounding Conductor Size?

MFortie

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Joined
Aug 9, 2010
Messages
921
Location
San Diego County
New meter pedestal, 220' run to subpanel, 100A @ 240V (single phase), using #1AWG copper (U/G in 2" conduit) yields a 2.72% voltage drop per Southwire's calculator.

Is a #6AWG adequate for the ground conductor?

Do the conductors need to be taped red / white in the handholes?

Thanks in advance.
 
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Jim greengo

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Joined
Sep 3, 2018
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7,415
Location
Behind my house
New meter pedestal, 220' run to subpanel, 100A @ 240V (single phase), using #1AWG copper (U/G in 2" conduit) yields a 2.72% voltage drop per Southwire's calculator.

Is a #6AWG adequate for the ground conductor?

Do the conductors need to be taped red / white in the handholes?

Thanks in advance.
Yes.
I'd pull 2 blacks,a white and a green so you dont have to worry about marking wires.
 

wyliesdiesels

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Joined
Aug 14, 2012
Messages
20,245
Location
Modesto, CA
New meter pedestal, 220' run to subpanel, 100A @ 240V (single phase), using #1AWG copper (U/G in 2" conduit) yields a 2.72% voltage drop per Southwire's calculator.

Is a #6AWG adequate for the ground conductor?

Do the conductors need to be taped red / white in the handholes?

Thanks in advance.
Southwire’s calculator sometimes has a habit of oversizing the wires (I have my suspicions of why) so it’s better to just do the calcs yourself to be sure. I posted the formula in the FAQ sticky
 
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wyliesdiesels

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Joined
Aug 14, 2012
Messages
20,245
Location
Modesto, CA
ok so i did the calcs using pvc conduit

#3 cu will give you a 4.4% VD
#2 cu will give you a 3.5% VD
#1 cu will give you a 2.9% VD

When you upsize ungrounded conductors, code requires the EGC to be upsized proportionally to the upsizing of the ungrounded conductors.

#3 is the min size for 100a and #3 is 52,633 cir mils. #8cu is the min size for 100a and #8 is 16,509

#1 is 83,690 cir mils so thats an increase of ~59.0067%. 1.590067 x 16,509 = 26,250 cir mils

thus you need #6 cu for the EGC which is 26,251 cir mils

good luck w/ your wallet. it will suffer greatly purchasing that much copper (over $2200) o_O :eek: 🤑
 
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