Anyone good with house wiring diagnosis?

Ron342 · 03-25-19, 01:43 PM

Yesterday a 120v breaker tripped in our bedroom circuit with very little connected. No recent construction efforts i can figure to cause it so unplugged everything, still trips so looked into the boxes.
First one i looked at had a socket and branched out in 2 directions from there.
s
Separated the 3 blacks, tried the breaker, no trip, located one black as the hot then read resistance between the black of each branch circuit and the still ganged together whites and also to the grounds. Both read high open circuits (megohms)
Then connected one branch black to the hot black, no trip, but when i tried the hot to the other branch black it tripped big.
What am i missing here? how can it trip on one branch if both branches are reading as open circuits between the blacks and ganged whites and grounds?
Case of your favorite beer (within reason) delivered as a reward!!

03-25-19, 01:43 PM	#1
Ron342 Apprentice EcoRenovator Join Date: Feb 2010 Location: Maryland Posts: 120 Thanks: 26 Thanked 12 Times in 8 Posts	Anyone good with house wiring diagnosis? Yesterday a 120v breaker tripped in our bedroom circuit with very little connected. No recent construction efforts i can figure to cause it so unplugged everything, still trips so looked into the boxes. First one i looked at had a socket and branched out in 2 directions from there. s Separated the 3 blacks, tried the breaker, no trip, located one black as the hot then read resistance between the black of each branch circuit and the still ganged together whites and also to the grounds. Both read high open circuits (megohms) Then connected one branch black to the hot black, no trip, but when i tried the hot to the other branch black it tripped big. What am i missing here? how can it trip on one branch if both branches are reading as open circuits between the blacks and ganged whites and grounds? Case of your favorite beer (within reason) delivered as a reward!!