Strange voltage readings

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Methvinmike

Member
Location
GA
First post on here so excuse me if it’s in the wrong place.
Went to a house for a service call. Homeowner says lights are getting dimmer and brighter without any interaction with the switch.
I’m thinking, lost a neutral.
had power company come by and check at meter, no issues. Will be replacing service cable tomorrow after all the troubleshooting I did today.Short section between main breaker and meter. Maybe 8’ away. Btw older house so meter and panel aren’t back to back and it’s an older ite panel and 3wire system. SEU cable. Voltages would fluctuate from 230 on 1 leg and 10 on the other and many combinations in between. All adding up to approximately 240. Also noticed ground rod is not installed, not that that matters. I’m usually very good at trouble shooting but I was kinda stumped. It would only fluctuate from standard with 4 of the breakers in the whole panel.
Is it possible that it’s something else other than a dropped neutral between panel and EMC transformer? I’ve never seen anything downstream of service affect voltages in this way. Lower voltage yes but increased voltage I have not. Any help would be appreciated. Readings of voltage taken from lugs at main breaker panel.
 

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
Agree. Voltage fluctuating like that means a lost neutral.

If this is only happening on 4 breakers, then you might very well be looking for a combination of a neutral bootleged between multiple circuits, with that neutral starting to fail.

-Jon
 

Methvinmike

Member
Location
GA
Agree. Voltage fluctuating like that means a lost neutral.

If this is only happening on 4 breakers, then you might very well be looking for a combination of a neutral bootleged between multiple circuits, with that neutral starting to fail.

-Jon

thanks for the response. Just odd I thought that I got those readings at the line side of the main breaker
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
thanks for the response. Just odd I thought that I got those readings at the line side of the main breaker
old SE cable between the old meter base and the main. Does it leave the meter base at the bottom and go through the wall?
Ive found many of these where water has made it’s way in the SE cable and corroded the neutral in the SE cable.
Most of them where we were checking for an electrician.
I usually have my guys take the tie wire off the truck and jumper between the meter base neutral and the main panel neutral to pin it down.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
I would confirm the voltages at the load terminals of the meter before doing anything else.

POCO guys are infamous for reporting proper voltages without having a load on the service.

Wire rarely goes bad; the issue must be at a termination, or on the POCO side of the meter.
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
I would confirm the voltages at the load terminals of the meter before doing anything else.

POCO guys are infamous for reporting proper voltages without having a load on the service.

Wire rarely goes bad; the issue must be at a termination, or on the POCO side of the meter.

I’ll vouch for that.
we bought four “Beasts” a few years ago.
Excellent tool, but only if they actually use it!

 

Methvinmike

Member
Location
GA
I would confirm the voltages at the load terminals of the meter before doing anything else.

POCO guys are infamous for reporting proper voltages without having a load on the service.

Wire rarely goes bad; the issue must be at a termination, or on the POCO side of the meter.
Poco
I would confirm the voltages at the load terminals of the meter before doing anything else.

POCO guys are infamous for reporting proper voltages without having a load on the service.

Wire rarely goes bad; the issue must be at a termination, or on the POCO side of the meter.
i did. Load terminals constant. guess I answered my own question lol. Thanks for leading me to water
 

Methvinmike

Member
Location
GA
I’ll vouch for that.
we bought four “Beasts” a few years ago.
Excellent tool, but only if they actually use it!

Load side of meter good voltage. Eight feet away not good. Thanks for your help. Redid all connections in panel. And it’s the old seu wire where the neutral is stranded all the way around the wire. Guess it’s possible it all corroded inside of jacket just hard to believe
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
Load side of meter good voltage. Eight feet away not good. Thanks for your help. Redid all connections in panel. And it’s the old seu wire where the neutral is stranded all the way around the wire. Guess it’s possible it all corroded inside of jacket just hard to believe
Believe it or not I find it all the time...
 
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