HELP - With Troubleshooting

wolfman56

Senior Member
Any suggestions are greatly appreciated.

The structure involved is a quad home.
The issue, all four tenants are complaining of light bulbs burning out too often. They say some bulbs only last a week. One tenant said he has even removed some bulbs from multi bulb fixtures to save on buying so many bulbs.

The utility says there are no problems on their end.
Since it affects all four units I suspect that there is a neutral problem between the structure and the transformer.

There is about 180? from transformer to the building, running under a parking lot that has drains. Also there is a fence post within 5? of the straight line from x-former to building. (You know what that could mean.) The feeder then terminates in a locked underground box 3? from the building. At this box four feeders go to four meters and panels. Each of the four units is set up as an individual service.

I think that due to having four households on this feeder, it is a balanced system most of the time, but there are some times when the balance is off enough that the neutral isn?t handling it causing an over voltage. This is an all electric building including heat and water heat, so there are plenty of two pole loads also.

I measured the voltage at an outdoor outlet during the day when no one was around and it was 120. (Note that in my area I?ve never seen a full 120 volts, this is the first time.) I also amped the ground rod and it was 0.
I could use some suggestions how to confirm a bad neutral or find the real problem. I know how to find a bad neutral on a single dwelling. But these are four apartments and access is not easy.

Thanks
Rick
 

Hv&Lv

Senior Member
Any suggestions are greatly appreciated.

The structure involved is a quad home.
The issue, all four tenants are complaining of light bulbs burning out too often. They say some bulbs only last a week. One tenant said he has even removed some bulbs from multi bulb fixtures to save on buying so many bulbs.

The utility says there are no problems on their end.
Since it affects all four units I suspect that there is a neutral problem between the structure and the transformer.

There is about 180? from transformer to the building, running under a parking lot that has drains. Also there is a fence post within 5? of the straight line from x-former to building. (You know what that could mean.) The feeder then terminates in a locked underground box 3? from the building. At this box four feeders go to four meters and panels. Each of the four units is set up as an individual service.

I think that due to having four households on this feeder, it is a balanced system most of the time, but there are some times when the balance is off enough that the neutral isn?t handling it causing an over voltage. This is an all electric building including heat and water heat, so there are plenty of two pole loads also.

I measured the voltage at an outdoor outlet during the day when no one was around and it was 120. (Note that in my area I?ve never seen a full 120 volts, this is the first time.) I also amped the ground rod and it was 0.
I could use some suggestions how to confirm a bad neutral or find the real problem. I know how to find a bad neutral on a single dwelling. But these are four apartments and access is not easy.

Thanks
Rick
I would say you need to check the voltage when everyone is around and living normally. Who is responsible for the secondary vault next to the building? Is this the utilities box or the building owners? What happens when a microwave comes on or when the refrigerator comes on?
 

ptonsparky

Senior Member
If you know how to find a bad neutral for one house, the procedure is the same for one building. Two tenants or ten. Especially if they all have the same symptoms. Who hired you? Building owner or tenant(s)? There is another thread started just lately that deals with lights flickering. Try gars method.
 

growler

Senior Member
The issue, all four tenants are complaining of light bulbs burning out too often. They say some bulbs only last a week. One tenant said he has even removed some bulbs from multi bulb fixtures to save on buying so many bulbs.

I tend not to believe those light bulb stories. A regular old incandescent lamp is not that sensitive to voltage spikes.

If you have a bad neutral and you are getting power surges there should be other more sensitive electronic equipment that's getting zapped.

Have they noticed any lights going bright and dim in different areas?
 

al hildenbrand

Senior Member
I measured the voltage at an outdoor outlet during the day when no one was around and it was 120. (Note that in my area I?ve never seen a full 120 volts, this is the first time.)
Rick,

This is an interesting report, to me.

In my area I commonly measure 125 to 127 volts at outlets about a system, so my handling of the "light bulbs burn out" complaint is a little different.

The commodity incandescent light bulb is rated for its average hours of life at 120 volts. With your lower PoCo nominal voltage, generally, then I'd expect something close to the actual advertised bulb life . . . however, if the bulbs are the cheapest that can be found on the local retail shelves, the rated life may well be an exaggeration, if not a fiction.

Another thought, given the distance from the transformer, I'd be curious what the open circuit voltage at the service disconnect (s) is when all the load of the building is off. Given the higher currents of the "all electric" four plex, the voltage drop on the service lateral alone, may account for part of the issue. In those moments when very few (or no) loads are on, the voltage drop will be the least, and the voltage to the lamps the highest.

A seven (7) volt rise of voltage above the lamp's rating voltage will result is a reduction of the life of the lamp by 52%. That is, a 900 hr ave life lamp will be expected to last 432 hr. If the lamp is normally left on all the time, that's eighteen (18) days.

I suspect that the four plex you describe in your OP will have a fluctuating voltage at the outlet . . . one question is "how much?"

I agree with growler that bulb burn out reports are suspect. There are simply a bunch of causes that lead to bulb failure. One other important one is that the lampholders are failing and have loose contacts, either to the lamp itself, or at the rivets or terminal screws.

If the service lateral really is failing, one will find the proof while looking at these other lamp failure causes.
 

220/221

Senior Member
Put your meter on A phase and load B phase to at least 1000 watts. The more the better.

Do the same test on B phase.

If the voltage goes significantly down on the loaded side and up on the unloaded phase, you have a neutral issue and it may be the cause of the lights burning out.

But...I doubt it. They would notice a brightening of the lights throughout the circuit/house.

I've heard the complaint many many times and never found and credible evidence. I blame Chinese lightbulbs.
 
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