troubleshooting branch circuit

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rickl

Senior Member
hi
i'm going to try to explain the situation, & maybe somebody can give me some advice or direction on troubleshooting this situation.
2 weeks ago i get a call from a new customer about receptacles not working in his kitchen, i get there and the circuit in question has 3 receptacles (one in the dining rm area, then the frig & a kitchen counter receptacle) and everything is working fine, good voltage at all three receptacles & refrig was working fine, so i figured that one of the stab-in receptacle has a bad connection, so i changed the 2 stab-in receptacles with non stab-in receptacle ( wires under the screws). & everything was working fine when i left. friday the same customer calls & the the same problem has come back, so i get there, plug my circuit tester in the first receptacle & it say's hot & ground wire reversed, so now i check the voltage hot to ground 120 volts hot to neutral 50 volts, neutral to ground 70 volts, so i tear apart the second receptacle & recheck my voltage & it has returned to normal 120volts from hot to neutral at first & second receptacle, tester say's wired correct. so now i'm thinking i have a bad wire between the second & third receptacles. Just to make sure, i put a load on the first receptacle & the voltage goes back to 50 volts between h & n, & the circuit tester say's ground & hot reversed, when the load is applied take the load away and it reads normal. so next i go check the voltage at the breaker while under load & its 120 volts, & now its getting late & the h/o makes a comment about having new siding put on the house 3 month's ago ( this house is only 10 years old) so i go into the attic & i notice the nails the siders used are sticking out 3/4" past the 2x4 ( mounted flat on the gable end of the roof)& the electrician who wired this house stuffed 4 homeruns in a 1/2" crack between the gable end & a 2x6 nailer which were likely hit by the sider nailing . at that point it was 7:00 and the ho had to leave so i'll be going back this week. my thinking is a nail between the neutral & ground, i also meggered the circuits & found no bad readings. so maybe it's not a nail or maybe my megger is bad. Has anybody run into a problem like this before.
thanks
i hope this all makes sense
 
S'mise

S'mise

Senior Member
Location
Michigan
If a nail was shorting neut to ground the plug would still have power. Sounds like a broken/loose neut to me. Throw that plug tester away and use a wiggie. Use an extention cord from a good circuit to use as a refrence. I would be looking at loose wirenuts and the neut buss connections at the panel.

(Hope this was not too long for Peter)
 
quogueelectric

quogueelectric

Senior Member
Location
new york
From what i think I just read you have an open neutral on your branch circuit wiring.
Because you have correct volts to ground it means the problem is not with poco or the service but in the branch ckt wiring where you have an unbalanced load on a 3 wire ckt.
Finding this in a modular home is whole nother post.
Leggo my wago!!
 
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rickl

Senior Member
i used a hair dryer as the load.
they all meggered around 100M.
{ I would be looking at loose wirenuts and the neut buss connections at the panel.}
i checked the connection at the panel, its fine, the power coming into the receptacle should be the homerun with no splices ( unless they spliced it behind the sheetrock, which wouldn't be the first time i found this)
thanks for the responses, sorry for the long post
i'm still thinking a nail damaged the wire in the attic, i will find out later this week.
 
JohnJ0906

JohnJ0906

Senior Member
Location
Baltimore, MD
I have discovered (through hard-won experience) that "hot-ground reversed" on plug-in testers is almost always an open or loose neutral with a load on the circuit. If you remove the load, it will read "open neutral"

I like my heat gun as a circuit load.
 
growler

growler

Senior Member
Location
Atlanta,GA
S'mise said:
I would be looking at loose wirenuts and the neut buss connections at the panel.
Click to expand...


For some reason people tend to miss the loose neutral connection at the buss. They look and see that it's connected and don't check to make sure it's clean and tight. If they don't check that one it will give them fits.
 
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charlietuna

Senior Member
From your post everything is not explained--- but i would first find and identify the home run by opening all the affected receptacles found and read each set of wires to be clear--using a wiggy(put the meggar in your truck-you'll scare the homeowner:D) read each set of wires end to end and to each other. Now you have all these wires hanging out of the wall and you are confident that end to end-you know where they go and there is not an extra set going where-ever??? Start back at the panel and reconnect the ground and the neutral and hot to the breaker. Then check that you have proper voltages(hot-ground-neutral) at your first outlet -- turn the power off--splice by pigtailing the hot-neutral-ground to the next box--cap off everything without installing any trim. Turn the power back on and check for proper voltages at the next box(s)(hot-neutral-ground)--etc.,etc, until everything has been pigtailed and checked! Turn the power off and install new trim ! No backstabbing--would you want that in your house???:D Check all outlets!
 
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hardworkingstiff

Senior Member
Location
Wilmington, NC
Once I reviewed an estimate that was inadequate. I asked the estimator why he bid it so low and he answered "I knew the job would go for (xyz)". He had a pre-concieved idea that convinced him he could do it for less.

One of the hardest things to do in troubleshooting is to not make up your mind pre-maturely and then miss some facts.
 
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rickl

Senior Member
charlietuna i did all the things that you posted, theres is only 3 receptacles on the circuit( kitchen sa). with only the homerun hooked up to the first receptacle & no load i have 120 volt h-g,h-n, & the tester say's wired correct. with a load, 50 volts h-n 70 volts n-g 120 volts h-g & the tester say's ground & hot reversed. & i checked all the connections at the panel, they are all tight. i went up in the attic & followed the cable from the panel through the 20' long crack( i mentioned in my first post) then i goes 20' under blowin insultion & down the wall to the first receptacle. the only places that i might find a splice is under the insultation ( which i'll check this week) or behind the sheetrock. thats kinda why i'm thinking that maybe a nail has damaged the cable. all the other lights & receptacles in the house are working fine.
thanks
 
electricalperson

electricalperson

Senior Member
Location
massachusetts
sounds like you have a loose neutral. if you had a completly missing neutral you wont have any voltage across from H to N. i would check junction boxes all the way back to the panel

i had a loose EGC once that read 60 v H to G. i found the loose splice. tightened it and it read 120v to G

was this part of a multiwire branch circuit by any chance?
 
R

rickl

Senior Member
yep the first receptacle was replaced 2 weeks ago
no multiwire branch circuit
i don't have a see snake,
 
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