breakers are off. Looking for possible explanation

Reply

  #1  
Old 05-03-18, 07:34 AM
Member
Thread Starter
Join Date: May 2018
Location: United States
Posts: 12
Received 0 Votes on 0 Posts
breakers are off. Looking for possible explanation

Hello,

Last few weeks I experience the same situation in the morning (not every). I have no light and 2 * 20A breakers are popped up and the main breaker as well.

1. If turn off one of the breakers manually, problem is gone . I replaced with new breakers - no changes.
2. It looks like there might be some relation to my dishwasher that I run at night. But I'm not sure about it. And it's not wired to any of mentioned breakers

This happens at night, so almost 0 load in the panel. Is there any good explanation of what could cause 2 small and main breakers to be tripped at the same time? For me it looks like a mystery, but I'm not an electrician.

Thanks
 
Sponsored Links
  #2  
Old 05-03-18, 07:46 AM
Member
Join Date: Feb 2014
Location: USA
Posts: 2,104
Received 0 Votes on 0 Posts
What do the 2 breakers feed??
 
  #3  
Old 05-03-18, 07:51 AM
Member
Thread Starter
Join Date: May 2018
Location: United States
Posts: 12
Received 0 Votes on 0 Posts
Outlets in the bedrooms - second floor. There is one in bathroom.

My main concern.. why main breakers is tripped..
 
  #4  
Old 05-03-18, 08:05 AM
Member
Thread Starter
Join Date: May 2018
Location: United States
Posts: 12
Received 0 Votes on 0 Posts
Pictures

https://drive.google.com/file/d/11mm...ew?usp=sharing
Name:  panel1.jpg
Views: 333
Size:  83.8 KB

https://drive.google.com/open?id=1Xq...bFAklb3xzlHT37
Name:  panel2.jpg
Views: 193
Size:  96.1 KB
 

Last edited by PJmax; 05-03-18 at 10:16 AM. Reason: added pics from links
  #5  
Old 05-03-18, 08:13 AM
Member
Join Date: Feb 2014
Location: USA
Posts: 2,104
Received 0 Votes on 0 Posts
What are you calling " main breaker" ? OK just saw the main breaker.
 
  #6  
Old 05-03-18, 08:15 AM
Member
Thread Starter
Join Date: May 2018
Location: United States
Posts: 12
Received 0 Votes on 0 Posts
The top one. That shuts off everything.
 
  #7  
Old 05-03-18, 08:19 AM
Member
Join Date: Feb 2014
Location: USA
Posts: 2,104
Received 0 Votes on 0 Posts
I would suspect a weak main breaker.
 
  #8  
Old 05-03-18, 08:25 AM
Member
Join Date: Feb 2014
Location: USA
Posts: 2,104
Received 0 Votes on 0 Posts
I would also verify that that breaker does feed the bedroom and bath.
 
  #9  
Old 05-03-18, 08:32 AM
Member
Thread Starter
Join Date: May 2018
Location: United States
Posts: 12
Received 0 Votes on 0 Posts
Breaker 13 does feed the bedroom outlet and the outlet in bathroom. I mentioned it in my first post.
If it happens because of the dishwasher.. why problem is gone if I turn off breaker 13? I have only laptop charger in during the night.

In theory, what could cause to trip off main breaker and small breakers at the same time?
 
  #10  
Old 05-03-18, 08:39 AM
Member
Join Date: Feb 2014
Location: USA
Posts: 2,104
Received 0 Votes on 0 Posts
I just wanted make sure nothing else is on circuit 13.
 
  #11  
Old 05-03-18, 08:49 AM
Member
Thread Starter
Join Date: May 2018
Location: United States
Posts: 12
Received 0 Votes on 0 Posts
A few outlets only and one of them is GFCI . This is 20A breaker.. It cannot trip 100A main breaker, right?
 
  #12  
Old 05-03-18, 10:05 AM
Member
Join Date: Feb 2014
Location: USA
Posts: 2,104
Received 0 Votes on 0 Posts
Your right, if something shorted out and drew over 100 amps you would have a burnt smell some where in the house.
 
  #13  
Old 05-03-18, 10:24 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 54,685
Received 521 Votes on 491 Posts
I've seen main breakers trip with a momentary short on a circuit. That in itself is not a problem.

What concerns me is that both 20A breakers feeding that multiwire branch circuit are tripping at the same time. That would seem to indicate a direct short happening between the red and black wire. That point would be where the circuit split into separate circuits.

It also looks like that MWBC is fed by UF cable. Is the circuit run up the outside of the house to the second floor. ?
 
  #14  
Old 05-03-18, 10:47 AM
Member
Thread Starter
Join Date: May 2018
Location: United States
Posts: 12
Received 0 Votes on 0 Posts
Now it starts to make sense for me... 2 hots might be shorted and this will trip the main breaker.
I don't see where the black cable goes on the picture. So let me check it tonight and I will try to verify where those 2 hots go.
I have the outlet outside, but I believe it sits on breaker #16. Again, I will confirm this tonight and post my results.

Thank you
 
  #15  
Old 05-03-18, 08:05 PM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: Twin Cities, MN
Posts: 13,065
Received 74 Votes on 66 Posts
Sounds to me like you have a line to line short. That could trip a main breaker and branch circuit breakers. Start looking at the boxes serving the multiwire circuit.
 
  #16  
Old 05-03-18, 09:19 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 54,685
Received 521 Votes on 491 Posts
What I'm calling UF is very dark gray. Look outside the house in that area. It could be loosely run on the surface or sleeved in some type of conduit. If you follow it to where it goes on the second floor it should take you right to the problem area.
 
  #17  
Old 05-04-18, 06:56 AM
Member
Thread Starter
Join Date: May 2018
Location: United States
Posts: 12
Received 0 Votes on 0 Posts
You're right about the cables. 2 breakers feed two hot wires in 1 grey (UF) circuit (cable). That cable goes outside right next to the electric panel. On the outside wall it goes straight up behind the leader and comes to the attic. On the attic I see big box with grey cable in and 6 yellow out (probably it's too much for 1 box? Looks like 4x4x4).
This grey cable feeds all second floor.

https://drive.google.com/file/d/1clA...ew?usp=sharing

https://drive.google.com/file/d/17aG...ew?usp=sharing

I cannot check the quality of the grey cable. I need a big ladder for it.
For now I have 3 possible reasons of why it can make a short.

1, Something's wrong in the box. - That would be the easiest fix.. But I doubt it's the reason.. Box looks fine visually
2, The company changes the siding for me last autumn. They could damage it?!
3. Squirrels. One year ago I had a big problem with the squirrels. They made a hole in old wood siding and had a nest on my attic. It was fixed and they did it again. This cable is right there where they built their hole. So they could damage it.


1 and 2 require to replace the whole cable.. So I will need to hire someone, just because it's very high location.

I'm still not sure why it tripped only at night.. Maybe temperature changes..
 
Attached Images   

Last edited by ray2047; 05-04-18 at 07:29 AM. Reason: A images.
  #18  
Old 05-04-18, 11:04 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 54,685
Received 521 Votes on 491 Posts
Looks like a good clean installation. if the problem was inside it would have to be in that box. You could turn the two breakers off and pull the splices out of the box looking for any insulation issues. If all ok there.... that leaves the problem outside and that will take a full visual inspection.

It would have to be fairly visible where the problem was outside. This isn't a simple cable nicking.... this is a well insulated cable getting shorted out.
 
  #19  
Old 05-04-18, 11:41 AM
Member
Thread Starter
Join Date: May 2018
Location: United States
Posts: 12
Received 0 Votes on 0 Posts
I bet it's damaged by squirrels. But that piece of cable is not reachable easily. It's located in narrow corner between the roof and attic floor (and might be between the outside walls). So I can inspect it only after complete removal.

If I install new cable, from what I know, I need a conduit at least 6-8' from the ground. My question is: Do I need to remove the insulation of UF cable of the part that will be in PVC pipe? I've heard somewhere that it's required to prevent the cables from overheating. But I cannot confirm it anywhere.
 
  #20  
Old 05-04-18, 11:44 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 54,685
Received 521 Votes on 491 Posts
You can run the UF thru a protection sleeve of PVC without stripping it.
The UF is required to be protected from damage. It looks like it was ok the way it was previously installed.
 
  #21  
Old 05-04-18, 11:47 AM
Member
Thread Starter
Join Date: May 2018
Location: United States
Posts: 12
Received 0 Votes on 0 Posts
Hmm.. How is it protected now? It's located behind the leader. I thought it should be in pvc pipe or other type of conduit.
 
  #22  
Old 05-04-18, 12:01 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 54,685
Received 521 Votes on 491 Posts
It's installed in the shadow of the leader. It would be pretty hard to damage it without taking the leader out too. You can sleeve it anywhere there is a chance of damage.

You could replace that UF with a 1/2" PVC conduit and eliminate the UF completely.
 
  #23  
Old 05-04-18, 12:09 PM
Member
Thread Starter
Join Date: May 2018
Location: United States
Posts: 12
Received 0 Votes on 0 Posts
I thought about replacing current UF cable with 2 UF cables with 1 hot wire inside each.

You mean use regular indoor cable and run it inside PVC conduit?
 
  #24  
Old 05-04-18, 12:18 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 54,685
Received 521 Votes on 491 Posts
If you replaced the run with PVC you would use 4 #12 THWN wires individually in the pipe.
 
Reply

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


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: