Go Back  DoItYourself.com Community Forums > Electrical, AC & DC. Electronic Equipment and Computers > Electrical - AC & DC
Reload this Page >

troubleshooting a breaker kicking off in mobile home circuit breaker panel

troubleshooting a breaker kicking off in mobile home circuit breaker panel

Reply

  #1  
Old 06-20-17, 06:02 PM
Member
Thread Starter
Join Date: Aug 2013
Location: United States
Posts: 65
Received 0 Votes on 0 Posts
troubleshooting a breaker kicking off in mobile home circuit breaker panel

One switch of a 15A tandem breaker kicks off approximately 1-1/2 to 2-seconds after resetting (pushing to full OFF, then back ON). No noise or arcing from breaker. Removed wire from the breaker kicking OFF, and inserted wire from the other switch on this tandem breaker (the circuit not kicking OFF), then breaker doesn't kick OFF.

This is a 14' x 70' mobile home. Have opened up all 120v wall receptacles (working & non-working), ceiling fixtures for lights (working/non-working), ceiling fans with lights (working/non~, ceiling fans without lights (working/non~, two wall lamp fixtures with ON/OFF switches (working/non~), all wall switch cover plates removed (working/non~)... all the above inspected...wire nuts removed (HOT & Neutral) and wire connections that were not twisted, were twisted.

All items shown are the non-working items. All X's are duplex receptacles, excepting the three outdoor lights (one next to the front entry door & two on the outside of the exterior kitchen wall).

When this breaker was turned ON, the two receptacles in MBR and the one on the exterior wall of 2nd BR momentarily turned on their receptacles (one receptacle of the two in the MBR had a lamp plugged into it; the other had a 3-prong tester plugged into it. The one on the exterior wall of 2nd BR also had a 3-prong tester plugged into it... so when the breaker was turned ON, the lamp and both 3-prong testers came on momentarily, just before breaker kicked OFF.

Both sets of wall switches shown are for kitchen and outdoor lights. The two outdoor lights on exterior wall of kitchen were not opened up/inspected. I assume these are end of circuit fixtures (well, one of them, anyway), as is the one near the front entry door.

I understand how working items that have two cables (one IN and one OUT) can be the cause of the next item in the same circuit not working, because of a bad (loose, corroded, overheated/brittle) connection on the outgoing cable, but found no such conditions. All wire connections in this old home were surprisingly clean & not overheated, not even where space heaters were used during winter. And if I'm forgetting one or two that might have been a little overheated, its wires were cut back to shiny copper and re-connected.

Circuit breaker panel is behind MBR entry door, which is at the end of the hallway shown at bottom of the sketch.

The only place I remember finding power IN & power OUT (2-cables in the box) was the receptacle to the left of the Front Entry door. This receptacle was on the wall to the left of the Front Entry door, and I have unintentionally omitted it from the sketch.

Could all these non-working items be on one circuit? The one that's kicking...?









Name:  Scan.jpg
Views: 231
Size:  21.2 KB
 

Last edited by plumducy; 06-20-17 at 06:26 PM.
Sponsored Links
  #2  
Old 06-20-17, 07:40 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 33,597
Received 13 Votes on 11 Posts
Will the breaker reset if no wire is connected to it? If so then
first unplug everything. If it still trips then you are going to need to open everything on the circuit and look for a short.
 
  #3  
Old 06-20-17, 08:46 PM
Member
Thread Starter
Join Date: Aug 2013
Location: United States
Posts: 65
Received 0 Votes on 0 Posts
ray2047
Will the breaker reset if no wire is connected to it? If so then
first unplug everything. If it still trips then you are going to need to open everything on the circuit and look for a short.


I assume it would reset with no wire connected to it, because it didn't trip with a good circuit wire connected to it. There isn't anything plugged into the circuit now. The aforementioned lamp in the MBR can be unplugged and it will still trip the breaker. I've already had everything opened and found no short.

Your suggestion has reminded me of another approach I've read about, but never tried yet... to open up an outlet in the middle of the non-working circuit, disconnect both cables, then see if breaker still trips. If it does, half of the circuit has been eliminated. Then pick another mid-point on the half that's still tripping, and repeat...

Maybe that will eventually isolate a pinched cable or a short I may have missed. Have seen a pinched cable situation in an old mobile home when working as a helper, long ago.
 

Last edited by plumducy; 06-20-17 at 09:14 PM.
  #4  
Old 06-20-17, 09:25 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 33,597
Received 13 Votes on 11 Posts
I've read about, but never tried yet... to open up an outlet in the middle of the non-working circuit, disconnect both cables, then see if breaker still trips.
Yes, that is similar to what my next suggestion would have been but...

Edit: Pete's suggestion below would be a better next step.
 

Last edited by ray2047; 06-20-17 at 10:57 PM.
  #5  
Old 06-20-17, 09:43 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 53,064
Received 371 Votes on 348 Posts
so when the breaker was turned ON, the lamp and both 3-prong testers came on momentarily, just before breaker kicked OFF.
That tells me that the short is far from the panel.

A dead short will trip the breaker the instant it is turned on. If the breaker holds for a second or two then there is a lot of resistance in the line. The resistance is caused by length of the wire. It could also be caused by something you haven't found yet.

The way I find these problems is to use a VERY low resistance ohm meter. It reads 0-10 ohms very accurately. The closer to the short..... the lower the reading.
 
  #6  
Old 06-20-17, 10:05 PM
Member
Thread Starter
Join Date: Aug 2013
Location: United States
Posts: 65
Received 0 Votes on 0 Posts
The way I find these problems is to use a VERY low resistance ohm meter. It reads 0-10 ohms very accurately. The closer to the short..... the lower the reading.
I'm not following you as to how you are using the ohm meter.
 
  #7  
Old 06-20-17, 10:30 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 53,064
Received 371 Votes on 348 Posts
Just connect the ohmmeter to the white and black at every device.
I stick the probes right into the receptacle.

What you might want to do is to identify the circuit at the panel and remove the white wire from the neutral bar and the black from the breaker.
Check for the short between black and white and black and ground.
 
  #8  
Old 06-21-17, 01:30 PM
Member
Thread Starter
Join Date: Aug 2013
Location: United States
Posts: 65
Received 0 Votes on 0 Posts
The way I find these problems is to use a VERY low resistance ohm meter. It reads 0-10 ohms very accurately. The closer to the short..... the lower the reading. Just connect the ohmmeter to the white and black at every device. I stick the probes right into the receptacle.
So I pick a point on the circuit with probes in receptacle hot & neutral side, then do the same at next receptacle in both directions from the first point. Whichever direction from the first point is lower ohms is the direction I go looking for the short, then the ohms reading will get lower as I get closer to the short. Correct?

If that's correct, I'm looking for a hot to neutral short, instead of a hot to ground short, because breaker didn't trip instantly. Correct?
What you might want to do is to identify the circuit at the panel and remove the white wire from the neutral bar and the black from the breaker.
Check for the short between black and white and black and ground.
You added this part so I could be sure which to start looking for (hot to neutral, or hot to ground, before I start probing receptacles with ohm meter?

Is it critical I use a very low resistance ohmmeter? How low? If the attached pic of my meters doesn't help, I'll look up their resistance values if I need to...
 
Attached Images  

Last edited by plumducy; 06-21-17 at 01:46 PM.
  #9  
Old 06-21-17, 09:03 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 53,064
Received 371 Votes on 348 Posts
Fluke T+pro...... very nice piece.

Correct.... identify if you are looking for a short to neutral or ground. Either one will cause the breaker to trip at the same speed. They are technically the same as they are tied in at the same place in the panel. The neutral creates the closed loop for power and the ground is strictly for safety.

Use the Fluke meter on the left. If it has the ability to set the OHMS scale.... set it to the lowest setting. You will need to hold the two probes together.... now move the probes where they attach to the meter. You want the meter to read as low as possible. Read what the meter says. This is your base low reading. This reading should be the same every time you short the probes together.

You will probably not see 0 ohms. You'll see like 1.2 ohms or some other low value. My meter has auto-zero when I hold the probes together and push the set button. The low value is not important as long as it's repeatable.

Check at the panel first.

These are only examples....
You measure nothing from ground to black and 2.9 ohms from white to black.
The short is between white and black.

Pick a point in the middle of the circuit. You'll see 2.1 ohms.
Pick a point further from the panels You'll see 1.5 ohms.

The lower the value.... the closer to the short you are.
You'll need to check carefully as the numbers may not change much. They may only be in a 2-5 ohm spread.
 
  #10  
Old 06-22-17, 05:03 AM
Member
Thread Starter
Join Date: Aug 2013
Location: United States
Posts: 65
Received 0 Votes on 0 Posts
Use the Fluke meter on the left. If it has the ability to set the OHMS scale.... set it to the lowest setting. You will need to hold the two probes together.... now move the probes where they attach to the meter. You want the meter to read as low as possible. Read what the meter says. This is your base low reading. This reading should be the same every time you short the probes together.
Thx much for your help... the detailed instruction, and the T+Pro comment.

Probes together, the Range button changed the range symbol from Megohms to K-ohms, to only Ohms, then the display reads ".1" ohms and doesn't change when I "disturb" the meter leads where they connect to the meter. I think that's what you wanted me to do.... to see if the reading changes any while I disturb those connections. If that's correct, it doesn't... I get the same .1 ohms reading repeatedly.

If I'm understanding correctly then, the meter's internal low resistance value (the ability to show very small changes) is important in this instance, because the difference in readings from receptacle-to-receptacle are indeed going to be very small, and it's important for the meter's starting point/"base low reading" to remain stable from receptacle-to-receptacle, so the differences measured are consistently accurate.
 
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
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: