3 Wire Feeder

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mbrooke

Batteries Included
Location
United States
Occupation
Technician
They were legal only to detached buildings with no metallic connections between them and the home up until recently. Subpanels within the same buildings have always been required to have a separate EGC of some type (wire or approved conduit).
 

tkb

Senior Member
Location
MA
So within the same structure, a 3 wire feeder to a sub panel was never legal?

Are talking about three phase without a neutral or a residential 120/240 feeder?

Either one is legal as long as they have a metallic conduit as a EGC.
 

Smart $

Esteemed Member
Location
Ohio
Are talking about three phase without a neutral or a residential 120/240 feeder?
...
Whichever the case may be, a feeder with a grounded conductor.

This brings up a noteworthy point. The three in three-wire feeder refers to the number of circuit conductors. EGC is not included. I believe most participating or reading this thread understand we are discussing the associated equipment grounding of said feeder on the load end.
 

tkb

Senior Member
Location
MA
Whichever the case may be, a feeder with a grounded conductor.

This brings up a noteworthy point. The three in three-wire feeder refers to the number of circuit conductors. EGC is not included. I believe most participating or reading this thread understand we are discussing the associated equipment grounding of said feeder on the load end.

The OP is kinda vague and I don't think that it's good to assume that it was clear to everyone.
 

A/A Fuel GTX

Senior Member
Location
WI & AZ
Occupation
Electrician
This is a 3 wire, 30A/240V, Black/Red/White feeder from a residence to a detached garage. No EGC present. Wiring method is UF. Grounded conductor is bonded to the sub panel. It was written up by a home inspector as being a violation. Sub panel has been in for 10 years.
 

kwired

Electron manager
Location
NE Nebraska
This is a 3 wire, 30A/240V, Black/Red/White feeder from a residence to a detached garage. No EGC present. Wiring method is UF. Grounded conductor is bonded to the sub panel. It was written up by a home inspector as being a violation. Sub panel has been in for 10 years.
The fact it supplies a separate building makes a difference. As mentioned 2008 NEC is the year all new installations were required to have separate EGC to separate buildings. Before then it was allowed, with conditions. If it is 10 years old it very well could have been legal at time of install - and still would be under later codes as long as you are not replacing the feeder.
 

tkb

Senior Member
Location
MA
This is a 3 wire, 30A/240V, Black/Red/White feeder from a residence to a detached garage. No EGC present. Wiring method is UF. Grounded conductor is bonded to the sub panel. It was written up by a home inspector as being a violation. Sub panel has been in for 10 years.

They were legal only to detached buildings with no metallic connections between them and the home up until recently. Subpanels within the same buildings have always been required to have a separate EGC of some type (wire or approved conduit).

I agree with mbrooke. See article in the 2002 NEC 250.32(B)(2)

(2) Grounded Conductor. Where (1) an equipment
grounding conductor is not run with the supply to the build-
ing or structure, (2) there are no continuous metallic paths
bonded to the grounding system in both buildings or struc-
tures involved, and (3) ground-fault protection of equip-
ment has not been installed on the common ac service, the
grounded circuit conductor run with the supply to the build-
ing or structure shall be connected to the building or struc-
ture disconnecting means and to the grounding electrode(s)
and shall be used for grounding or bonding of equipment,
structures, or frames required to be grounded or bonded.
The size of the grounded conductor shall not be smaller
than the larger of
(1) That required by 220.22
(2) That required by 250.122
 

tkb

Senior Member
Location
MA
The fact it supplies a separate building makes a difference. As mentioned 2008 NEC is the year all new installations were required to have separate EGC to separate buildings. Before then it was allowed, with conditions. If it is 10 years old it very well could have been legal at time of install - and still would be under later codes as long as you are not replacing the feeder.

Legal as long as there were no other metallic paths between the buildings, like a water pipe, phone or CATV cable, branch circuit switching, gas piping or water piping.
 

iwire

Moderator
Staff member
Location
Massachusetts
Legal as long as there were no other metallic paths between the buildings, like a water pipe, phone or CATV cable, branch circuit switching, gas piping or water piping.

I do not know this to be a fact but I would still bet money that those restrictions are much newer then the allowance to use the neutral as the grounding means at remote structures and buildings.
 

tkb

Senior Member
Location
MA
I do not know this to be a fact but I would still bet money that those restrictions are much newer then the allowance to use the neutral as the grounding means at remote structures and buildings.

It is mentioned in the 2002, I'm not sure if it is in an earlier version. 2002 is as far as I go back electronically.
 
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