ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Top Posters(30 Days)
Trumpy 5
Recent Posts
What do you do?
by gfretwell. 09/24/17 12:05 PM
75 kva tranformer
by sparkync. 09/23/17 06:41 PM
Another generator question
by gfretwell. 09/23/17 04:15 PM
Supporting conduit bodies
by ghost307. 09/18/17 12:12 PM
Thermal Imaging Camera upgrade
by Potseal. 09/18/17 11:57 AM
New in the Gallery:
Gallery Test
Popular Topics(Views)
240,948 Are you busy
176,744 Re: Forum
168,595 Need opinion
Who's Online Now
0 registered members (), 47 guests, and 8 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate This Thread
#180967 - 09/17/08 09:58 PM GFI outlet on knob & tube  
HCE727  Offline
Member
Joined: Nov 2005
Posts: 186
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.


Hank

Work Gear for Electricians and the Trades

#180968 - 09/17/08 10:11 PM Re: GFI outlet on knob & tube [Re: HCE727]  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,118
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.


Greg Fretwell

#180971 - 09/17/08 10:38 PM Re: GFI outlet on knob & tube [Re: gfretwell]  
twh  Offline
Member
Joined: Mar 2004
Posts: 918
Regina, Sask.
I put gfi protection on K&T fairly often.


#180978 - 09/17/08 11:33 PM Re: GFI outlet on knob & tube [Re: twh]  
EV607797  Offline
Member
Joined: Oct 2006
Posts: 745
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."

#181008 - 09/18/08 09:02 PM Re: GFI outlet on knob & tube [Re: EV607797]  
HCE727  Offline
Member
Joined: Nov 2005
Posts: 186
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.


Hank


Member Spotlight
RonKipperDatacom
RonKipperDatacom
Kansas City, KS
Posts: 30
Joined: January 2013
Show All Member Profiles 
Featured:

2017 Master Electrician Exam Preparation Combos
2017 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Shout Box
Powered by UBB.threads™ PHP Forum Software 7.6.0
Page Time: 0.017s Queries: 15 (0.004s) Memory: 0.7687 MB (Peak: 0.9100 MB) Zlib enabled. Server Time: 2017-09-26 05:28:27 UTC