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#180967 - 09/17/08 06:58 PM GFI outlet on knob & tube
HCE727 Offline
Member

Registered: 11/11/05
Posts: 190
Loc: Delaware County, PA, USA
Years back I installed a GFI outlet in a bedroom that was wired in K&T. Every time I turned on the hallway 3-way, the GFI tripped. Has anyone ever had a problem with GFI's and K & T? After that I now install non-gounding outlets on K & T.
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Hank

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#180968 - 09/17/08 07:11 PM Re: GFI outlet on knob & tube [Re: HCE727]
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9012
Loc: Estero,Fl,usa
I bet you have a short to ground on a neutral. That could have gone on unnoticed forever. It could also be high resistance ground on a hot (petrified mouse or something.
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#180971 - 09/17/08 07:38 PM Re: GFI outlet on knob & tube [Re: gfretwell]
twh Offline
Member

Registered: 03/11/04
Posts: 892
Loc: Regina, Sask.
I put gfi protection on K&T fairly often.

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#180978 - 09/17/08 08:33 PM Re: GFI outlet on knob & tube [Re: twh]
EV607797 Offline
Member

Registered: 10/25/06
Posts: 756
Loc: Fredericksburg, VA, USA
My guess would be that the far end of that three-way circuit (light fixture) is getting it's neutral from something other than the GFI's LOAD neutral output.

Basically, your hot LOAD output is feeding the point wire of the 3-way switch at one end, and the point wire at the other end is feeding the fixture. Problem is that the fixture is getting it's neutral elsewhere, even if it is on the same circuit ahead of the GFI.

Do you need to have the GFI protecting the circuit downstream form the device itself? It's a bit odd for K&T circuits to loop from device to device, but this does happen. Why not just put the in and out wiring on just the LINE terminals and be done with it?
_________________________
---Ed---

"But the guy at Home Depot said it would work."

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#181008 - 09/18/08 06:02 PM Re: GFI outlet on knob & tube [Re: EV607797]
HCE727 Offline
Member

Registered: 11/11/05
Posts: 190
Loc: Delaware County, PA, USA
This happened to me years ago. There was only one hot and one neutral in the box that I installed the GFI in.
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