4wire for 3 wire system

Daja7

Senior Member
odd question and i should know this, installing a service upgrade and customer has 4 wire ser cable he wants me to use. from meter to panel only requires 3 wire SE. is there a code that prohibits this?
 

102 Inspector

Senior Member
Location
N/E Indiana
Actually inspected the same thing yesterday on a detached garage. New service with 4-wire, installer used neutral and grounding conductor as parallel. Connected to grounding lug in meter base(utility does not ground from meter base) and connected to terminal in load panel. He said the guy at the supply shop had a short piece he would give him. Less then 2 feet total distance.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
Actually inspected the same thing yesterday on a detached garage. New service with 4-wire, installer used neutral and grounding conductor as parallel. Connected to grounding lug in meter base(utility does not ground from meter base) and connected to terminal in load panel. He said the guy at the supply shop had a short piece he would give him. Less then 2 feet total distance.
Did he use a double lug or put them both under the same lug? What size wire? Can't parallel under 1/0. I wonder if the equipment grounding conductor is 1/0 or larger
 

Daja7

Senior Member
thanks, that is what i thought. If used as a parrallel do they not need to be the same size. just an aside :?
 

102 Inspector

Senior Member
Location
N/E Indiana
Conductors were #2 alum and were not connected under a double barrel lug. This meter base had the neutral lug in the center of the meter base with a grounding lug beside it. The panel had the neutral connected at normal location, with 4th wire connected to grounding busbar with approved lug. Did I miss something with paralelling less than 1/0. Never even thought of it while I was standing there. First mistake this year.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Did he use a double lug or put them both under the same lug? What size wire? Can't parallel under 1/0. I wonder if the equipment grounding conductor is 1/0 or larger
Even if #1/0 or larger the two conductors in parallel would need to be the same size and have the same characteristics, like both being insulated or bare.
 

Daja7

Senior Member
so bottom line is nothing prevents using 4 wire for 3 wire application if i leave both ends of the spare wire disconnected and taped up?
 
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