voltage drop for residential

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zappy

zappy

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i have a run of a 130ft one way to feed a studio.one 20amp circuit, one 15amp circuit.15amp to some regular outlets.the 20 amp circuit i am putting a gfci outlet.i was going to pull 12awg thhn through conduit on building.if i pull a black,red,white mwbc do i count one way for vd or 130ft+130ft? do i use 240v.or 120v. ?will the gfci outlet work properly since its sharing a neutral with other outlets?the formula i'm using is L x I X R DIVIDED BY 1000 = VD.should i use table 9 alternating current resistance or table 8 conductor properties?
 
total circuit length appears to be 260'
are you installing a GFCI Breaker??
Is any portion of the run outdoors or underground??

Vd= k X L X Iline / CMA
or

Vd = E line / R line

break it out to a couple of questions
 
one gfci outlet.conduit ran on building outdoors.

one gfci outlet.conduit ran on building outdoors.

cpal said:
total circuit length appears to be 260'
are you installing a GFCI Breaker??
Is any portion of the run outdoors or underground??

Vd= k X L X Iline / CMA
or

Vd = E line / R line

break it out to a couple of questions
Click to expand...
so your saying i use 260ft even if its a mwbc i'm pulling?on the 20amp circuit im using the 80%rule so 16amps im using for the calculations.i'm getting about 6 1/2% vd.
 
zappy said:
...run of a 130ft...i was going to pull 12awg thhn through conduit...
Click to expand...
Without even doing a calculation, I'd pull no smaller than 10 AWG for 20A hot & neutral, and no smaller than 12AWG for the 15A hot.
 
Smart $ said:
Without even doing a calculation, I'd pull no smaller than 10 AWG for 20A hot & neutral, and no smaller than 12AWG for the 15A hot.
Click to expand...


I concur. Pull a 10.

next time break up your post had a hard time reading it.

for vd use table 8
 
Dominator said:
...next time break up your post had a hard time reading it.
...
Click to expand...
Your reply is to my post!

How should I break up a one sentence post to make it easier to read, sir? :wink:
 
I come up with a 6.8 % drop. The FPN's in Art. 210.19 and Art. 215 2(A)3 say no more than 5%. Not required but I would do what others here have said and run #10 & #12.
 
Dominator said:
next time break up your post had a hard time reading it.
Click to expand...


Here ya go.:D

i have a run of a 130ft one way to feed a studio.

one 20amp circuit, one 15amp circuit.

15amp to some regular outlets.

the 20 amp circuit i am putting a gfci outlet.

i was going to pull 12awg thhn through conduit on building.

if i pull a black,red,white mwbc do i count one way for vd or 130ft+130ft?

do i use 240v.or 120v. ?

will the gfci outlet work properly since its sharing a neutral with other outlets?

the formula i'm using is L x I X R DIVIDED BY 1000 = VD.

should i use table 9 alternating current resistance or table 8 conductor properties?
Click to expand...
 
GFCI question.

GFCI question.

No one answered your question on the GFCI properly working with shared neutrals. Same neutral, two different circuits? No, it wil not, nor will an AFCI. The GFCI looks for an imbalance between the ungrounded and grounded. With a shared neutral, (grounded), you can see why now.
 
76nemo said:
No one answered your question on the GFCI properly working with shared neutrals. Same neutral, two different circuits? No, it wil not, nor will an AFCI. The GFCI looks for an imbalance between the ungrounded and grounded. With a shared neutral, (grounded), you can see why now.
Click to expand...

The neutral cannot be shared downstream of the GFCI.

If it is a GFCI recep in the studio, it should be fine. Just don't run the neutral from the load side of the GFCI recep to any outlets on the other half of the MWBC. If a GFCI breaker in the panel, then what 76nemo said.
 
dhducati said:
The neutral cannot be shared downstream of the GFCI.

If it is a GFCI recep in the studio, it should be fine. Just don't run the neutral from the load side of the GFCI recep to any outlets on the other half of the MWBC. If a GFCI breaker in the panel, then what 76nemo said.
Click to expand...


Sorry, should of been more clear. I had to go back and read "outlet":rolleyes:

EDIT: phrasing
 
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