Sizing ground wire for voltage drop

Status
Not open for further replies.

dpo

New member
Location
hudson new york
I have resently needed to increase a 20 outlet circuit to #4 wire for voltage drop.
Unfortunatly the conduit has already been sized 3/4".
2#4 and 1-#12 ground wire will meet the fill calculations.
I have read NEC section 250-118 and 250-122.
The conduit system is RMC with all threaded joints back to the source.
My question is this an acceptable installaion?
The rigid conduit is an acceptable EGC by itself.
The #12 is a supplimental parallel EGC.
Is this correct.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
The rmc is a sufficient equipment grounding conductor however if you run an actual conductor it must be sized proportionately as 250.122(B) requires. This would mean a #4 equipment grounding conductor.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
As Dennis stated the proportional ratio is 1 to 1 so your EGC must be the same size as the phase conductors. Either use a #4 EGC or remove the #12 completely and only use the raceway as the EGC. The NEC makes no provisions for a smaller EGC when used in parallel with a metallic raceway that qualifies as an EGC.
 
Status
Not open for further replies.
Top