Fixed it but stump

Status
Not open for further replies.
K

kbrandt

Member
Location
arizona
Hi guys, maybe you can answer this problem and what was going on at this house.

Lady called and no power in a couple rooms. House is 50 years old. O.K. went over and checked the panel, handy man put 2 #12 on one 20 amp breaker, seen it before no big deal.

Well when I turned the 2 breakers on that were tripping they held for about 20 seconds and tripped both, one sp with one wire (which had nothing to do with the breaker that was losing power or tripping) it tripped first and then the other sp with 2 wires tripped about 5 seconds after the first one.

Took amp reading on all 3 wires and read maybe 1 amp on 2 of them and the third which was on the same breaker with another wire that had one amp and it read 53 amps. House is all gas.

Took the wire reading 53 amps and added a breaker to make it legal and it cleared everything and then read maybe one amp. Everything started working correctly and no problems since then.

Why was I reading 53 amps when it was on a sp breaker with another wire and then when I put it on its own breaker work fine.

They were not the same phase either.
Can someone tell me what was happening here.
Thanks for any feedback.
 
The key may be in "they were not on the same phase".
On more than one occasion I have found alterations that resulted in one circuit being fed by two breakers. If a wire is moved so the breakers are on opposite phases you, of course, have a short.
With one breaker off did you check to see if you had any "backfeed" to the other ?
 
120v/53A = 2 ohms, which is an awfully long length of #14.

I think the 53 A over several seconds melted the short that was somewhere in the house, just before you added the third breaker.
That's why it doesn't make sense; there was a change in the circuitry that you didn't make.

Do all the appliances still work?
 
Everything is working great. After I put in a breaker and moved the double wire on one breaker. No problems and it has been 4 days.
 
If you do have a incident as described in poat #2 where the circuit is connected to two breakers you would have no apparent problem as long as both breakers are on the same phase but you also would not have proper protection. I would suggest you check for a "tie" to assure you don't have a circuit fed by two breakers.
 
As Augie said, this can burn a house down real fast if one of these circuits shorts, I would at least call the owner and just tell him you need to check something to make sure its safe, if you can get back in just shut off one of the breakers and check for voltage on the lug of that breaker, if it is hot then you have two circuits tied together with the ability to supply more then 40 amps to conductors that are only rated for 20, or 30 amps to conductors only rated for 15 amps.

Trust me, this is exactly what happened to one of our electricians at the last company I worked for, and yes the house burnt to the ground
 
I thought Gus had the answer but there is no way the circuit would be on for 20 seconds if there was a 240V short.

The answer that the short may have blown clear is a possibility also. Hard to tell with the info given. I would like to know where the circuits involved every on opposite phases?
 
If Mr. Brandt goes back and reconnects the orig. setup and the breakers now hold, and I think this is likely, then something has changed.
If a microgap has been melted in a conductor it may someday reclose with day/night temperature changes.

In any case, I'd go back one more time with a definite procedure for testing for as many likely causes as possible. It shows due diligence and it may uncover more wiring problems.
For sure the wiring in this old house is suspect and a cable manuf. has told me that 50 years is the lifespan of Romex. He wouldn't say how the end of life for a cable was defined but I imagine it is an insulation resistance degradation at an increasing rate.
 
Last edited:
Why are they called handymen when they f things up all the time? Oh, never mind he is handy for us; I get it now!!
 
G._S._Ohm said:
If Mr. Brandt goes back and reconnects the orig. setup and the breakers now hold, and I think this is likely, then something has changed.
If a microgap has been melted in a conductor it may someday reclose with day/night temperature changes.

In any case, I'd go back one more time with a definite procedure for testing for as many likely causes as possible. It shows due diligence and it may uncover more wiring problems.
For sure the wiring in this old house is suspect and a cable manuf. has told me that 50 years is the lifespan of Romex. He wouldn't say how the end of life for a cable was defined but I imagine it is an insulation resistance degradation at an increasing rate.
Click to expand...

Does anyone have a reference guide or life span table for romex?
 
Status
Not open for further replies.
Top