Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 02-25-2009, 06:37 PM   #1
Newbie
 
Join Date: Feb 2009
Posts: 21
Share |
Default

gfci in main feeding sub panel problem


I have a 50 amp double pole gfci in my main panel feeding my detached garage with 6/3 wire and i was having a problem with the gfci tripping randomly anywhere from a couple hours apart to a week apart. In the sub panel was one 30 amp breaker protecting the 12/2 wiring to the outlets. And the 2 lights in the garage was hoked straight to the other 110 lug. (Sub-panel has two 110 hots, neutral and ground). I knew the 30 amp breaker should have been a 20 amp so I changed it out. My biggest question is with this sub panel being fed with a 50 amp gfci are the grounds and neutrals supposed to be terminated at their own terminal block (neutral to neutral block, and ground to ground block in the sub-panel)? I have read that if the main breaker box has a standard 2 pole breaker feeding the sub then yes the grnds to grnd block and neut. to neut. block. But what if the sub panel is fed by a gfci? I changed the sub panel box to a 4 space 125 amp box and hooked to grns to grnd block and neut. to neut. block and also installed a ground rod into the earth and ran the 6ga grnd wire from the rod to the gdrn terminal block. (It previously had no grnd rod) And now the main 50 amp gfci trips almost immediately. So i hooked all the grounds and neutrals together and it works fine but I still need t know what is the proper way this needs to be wired. BTW the subpanel now has the 20 amp breaker and a 15 amp arc fault breaker protecting the circuits. Thanks in advance!


Last edited by scott2332; 02-25-2009 at 06:40 PM.
scott2332 is offline   Reply With Quote
Old 02-25-2009, 07:19 PM   #2
Member
 
Join Date: Jul 2008
Location: NW of D.C.
Posts: 5,990
Default

gfci in main feeding sub panel problem


Quote:
Originally Posted by scott2332 View Post
gfci tripping randomly anywhere from a couple hours apart to a week apart.
From another thread on this forum, if you're near a radio station you may need to retrofit an RF filter available from the manuf.

Yoyizit is offline   Reply With Quote
Old 02-25-2009, 07:33 PM   #3
Licensed Pro
 
Join Date: Mar 2007
Location: SC
Posts: 1,528
Default

gfci in main feeding sub panel problem


Make sure your neutral bus is isolated from the panel enclosure and from the ground bus. Any contact between the two will cause the gfci breaker to trip.
__________________
"Life is hard. Life is harder when you're stupid." John Wayne
HouseHelper is offline   Reply With Quote
Old 02-25-2009, 07:40 PM   #4
Member
 
Join Date: Oct 2007
Posts: 2,294
Default

gfci in main feeding sub panel problem


It's on a GFCI because........?
220/221 is offline   Reply With Quote
Old 02-25-2009, 08:38 PM   #5
Member
 
Join Date: Nov 2007
Location: Nashua, NH, USA
Posts: 6,856
Default

gfci in main feeding sub panel problem


Is your main panel GFCI braker feedint the subpanel tripping even if all the branch circuits in the subpanel have their breakers turned off? There could have been a ground fault in one of those branch circuits.
__________________
Stop wasting time re-adjusting the pattern. Have several lawn sprinklers, one for each pattern.
AllanJ is offline   Reply With Quote
Old 02-25-2009, 09:12 PM   #6
Newbie
 
Join Date: Feb 2009
Posts: 21
Default

gfci in main feeding sub panel problem


The GFCI only trips when i turn the 2 breakers to the on position in the subpanel. I didn't do them 1 at a time and check if it is just one breaker causing it to trip when i turn it on. I will do them 1 at a time however just to see right now. The previous owners put the GFCI in before I moved here and they may have done it because they didn't bury the wire deep enough possibly fearing someone would dig into it?? Neutral bus has isolators on it preventing it from grounding to the box and the ground bar. The gfci in main panel is properly wired with white pigtail to neutral/ground bar and 2 hots and neutral to gfci from the feed wire to sub-panel.
scott2332 is offline   Reply With Quote
Old 02-25-2009, 09:29 PM   #7
Newbie
 
Join Date: Feb 2009
Posts: 21
Default

gfci in main feeding sub panel problem


Ok, I just went out there and turned on the 20 amp first and it immediately tripped the gfci in the main panel. I left both subpanel breakers off and reset the gfci and then turned the 15 amp afci to on and all was fine until i plugged in a drop light and switched the light to on which tripped the 15 amp afci and the 50 amp gfci in main. So do you think that the grounds to ground block and neutral to neutral block in the sub panel is correct wiring if sub is being fed from a 50 amp gfci?
scott2332 is offline   Reply With Quote
Old 02-25-2009, 09:30 PM   #8
Electrician
 
Join Date: Aug 2007
Location: Connecticut, Litchfield
Posts: 2,015
Default

gfci in main feeding sub panel problem


One thing you have to remember is that itonly takes 5ma to trip a GFCI, so it could be a TOTAL of all your breakers that are making it trip, not just 1 or 2 circuits. I would remove that GFCI breaker.
chris75 is offline   Reply With Quote
Old 02-25-2009, 10:02 PM   #9
UAW SKILLED TRADES
 
Stubbie's Avatar
 
Join Date: Jan 2007
Location: Kansas
Posts: 4,865
Default

gfci in main feeding sub panel problem


Scott

You just changed to a 125 amp 4 space panel, and now your 50 amp gfci is tripping the instant you turn on a breaker in that subpanel. I can say with some certainty that your neutral and ground are not separated at the new subpanel and this is why your gfci is tripping.

The fact that you have a 50 amp gfci has no bearing on how the sub-panel is wired, whether you need a ground rod or not or how deep the cable is buried. However it sounds like you have a 4 wire feed to the sub-panel. 2 hots a neutral and a ground. You should have 2 bars in the sub panel if you have 4 wires feeding it. One is the neutral and one is the ground. The fact that it is on insulators only makes the neutral bar able to be isolated by not installing the main bonding jumper. If the green screw or whatever is used to bond the two bars in the sub panel is installed that is why your gfci is tripping. You need to check and remove it if you have 4 wires feeding the sub.

Can you post the model and make of your sub-panel?
__________________
" One nice thing about the NEC articles ... you have lots of choices"

Stubbie
Stubbie is online now   Reply With Quote
Old 02-25-2009, 10:13 PM   #10
Newbie
 
Join Date: Feb 2009
Posts: 21
Default

gfci in main feeding sub panel problem


one thing i just thought of and should have mentioned is that yesterday when my dad and i were looking over the wiring and installing the new sub panel i remember seeing a white wire connected to a black wire (it wasn't coded hot but should have been) and it went to the lights from the switch i believe. The garage has one single pole switch and 2 lights that turn on when switch it on. Anyhow my dad didn't like the idea of them wire nutting those inside the sub panel so he added 14/2 wire to go all the way to the switch along with the other 14/2 and when he done this he ended up connecting white to white and black to black in a new junction box which may be where the problem is now that I think of it. Without looking at the wiring at the lights in the garage i'm guessing it could be similar to this:http://www.electrical-online.com/two...yoneswitch.htm
scott2332 is offline   Reply With Quote
Old 02-25-2009, 10:20 PM   #11
Newbie
 
Join Date: Feb 2009
Posts: 21
Default

gfci in main feeding sub panel problem


it is a seimens sub panel with seimens breakers, it did come with a bonding bar but i never installed it. I'll bet what my dad did with the wires in the junction box is the problem. Now with that breaker off for the lights the other breaker and the gfci in main panel would only trip when plugging into a receptacle in garage and switching the drop light or any other load to the "on" postion. Guessing power is trying to feed through the neutral when this happens causing it to trip?
scott2332 is offline   Reply With Quote
Old 02-25-2009, 11:10 PM   #12
UAW SKILLED TRADES
 
Stubbie's Avatar
 
Join Date: Jan 2007
Location: Kansas
Posts: 4,865
Default

gfci in main feeding sub panel problem


The neutral current must equal the current in the hot wire. If 5 amps are flowing in the hot 5 amps must be flowing in the neutral. It is almost always neutral current getting to ground that causes a gfci to trip. So check for any neutral and ground connections.
__________________
" One nice thing about the NEC articles ... you have lots of choices"

Stubbie
Stubbie is online now   Reply With Quote
Old 02-25-2009, 11:17 PM   #13
Newbie
 
Join Date: Feb 2009
Posts: 21
Default

gfci in main feeding sub panel problem


also just wanted to ad to my last post that at the light switch it is black wire into switch and black out of switch and white wire wire nutted to other white. I will have to ask my dad tomorrow if the switch was originally wired with a black and a white (hot coded) wire. uggghhhh I wish he would have left the wiring alone at least until we got the new sub panel in and tried it. I will double check the wiring tomorrow everywhere and see if I need to re-wire the light circuit back to how it was before dad re wired it. Thanks for all the help!


Last edited by scott2332; 02-25-2009 at 11:53 PM.
scott2332 is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Converting Main Panel to Sub: How to jumper? HomeOwner42 Electrical 46 02-19-2009 03:28 PM
main panel splice thriemer Electrical 1 02-16-2009 09:50 PM
Nuetral from feeder cable to main panel question? TW Lucas Electrical 14 05-08-2008 11:33 AM
Replace main panel or use subpanel? MasterofNone Electrical 8 02-12-2008 12:24 AM
Splice in Neutral to Panel - OK or Not? allpraisebob Electrical 4 08-12-2006 05:54 AM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.