Lights dimming resident.

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aftershock

aftershock

Senior Member
Location
Memphis, TN
A troublecall today. Lights dimming and then going bright.
Pull the meter check voltage on line side. 123/v from each leg to neutral.
Plug meter in. When lights dim checked load side of meter.
100/v to neutral on one leg, 143/v to neutral on the other.
Loose neutral is what I am figuring. Maybe the connection at the service? So I check the POCO side of the connections and get the same 100/v-143/v.
I checked all other connections, nothing loose, nothing burnt.
I figured the problem must be at the pole or further. Sound right? Or would the problem still be on the HO side of the POCO connections?
 
The HO had the POCO out about 2 times already and they told her that the voltage was OK at the meter but not OK in the panel.
Im thinking they pulled the meter and checked the line side, then plugged the meter back in and check the load side.
Im hoping the way I described that I did it shows that it has to be on the POCO side.
I did have her call the POCO and I told them to check for a loose neutral at the pole.

I figured I would ask here if the way I did my checks was correct as well as my conclusion as to where the problem should be found.

I kinda figured the POCO guys should know if not as much, but more than me on how to check this stuff.
 
aftershock said:
The HO had the POCO out about 2 times already and they told her that the voltage was OK at the meter but not OK in the panel.
Im thinking they pulled the meter and checked the line side, then plugged the meter back in and check the load side.
Im hoping the way I described that I did it shows that it has to be on the POCO side.
I did have her call the POCO and I told them to check for a loose neutral at the pole.

I figured I would ask here if the way I did my checks was correct as well as my conclusion as to where the problem should be found.

I kinda figured the POCO guys should know if not as much, but more than me on how to check this stuff.
Click to expand...

More than once I have had to call the poco and get them to come back. I had a very similar problem years ago. I finally called the engineer and he said oh yeah that's a classic loose neutral. I asked him to please tell his men that and fix the dang thing. After 3 trips it finally got fixed.

Without a load the loose neutral will not show it's ugly head.
 
aftershock said:
The HO had the POCO out about 2 times already and they told her that the voltage was OK at the meter but not OK in the panel.
Im thinking they pulled the meter and checked the line side, then plugged the meter back in and check the load side.
Im hoping the way I described that I did it shows that it has to be on the POCO side.
I did have her call the POCO and I told them to check for a loose neutral at the pole.

I figured I would ask here if the way I did my checks was correct as well as my conclusion as to where the problem should be found.

I kinda figured the POCO guys should know if not as much, but more than me on how to check this stuff.
Click to expand...

If unbalanced with meter in and load on and your checking at weather head then it must be them. I think they simply have an unqualified line man. You did your job right
 
Thanx.
I just hate leaving a job and thinking to myself "should I have checked something else?"
I dont run across this type of thing much, but I learned from a few years back that that type of reading is a loose neutral. I had used my soleniod tester at first and could feel the difference in the "kick" of the soleniod and that's when I grabbed my DMM.
 
Rick, the advice above is right on. The problem is always on the line side of whatever point you check and find the imbalance. Can you be there when the POCO comes back?

The POCO guys often don't grasp the need for a load to show the imbalanced voltages, and often blame lack of ground rods for not compensating for the problem. :roll:
 
Assuming you have resolved all possibilities with anything from the meter to the house. It has been my expierence that you have to force the POCO's hand and maybe hold it during the investigation.
 
I've had similar calls where the POCO was there before me. Last time I told the customer they had a bad transformer and the mentioned POCO said to them it wasn't their issue and to call an electrician. I then knocked on the doors of the three other houses on the transformer and all of them experienced identical problems.

The POCO isn't always correct in their assessment.
 
I had one that fooled me!
I was called out for the same thing... dimming lights. I did the usual inspection of lugs, voltage readings... of course it wasn't "open" when I was there. It was an intermitant problem. Anyway, I decided it was the utility co.'s problem and advised the customer to call them. 2 days later I was called back... Utility said it's not their problem...again, I checked "everything"! (lights were normal while I was there of course!) I said to call the utility again!
2 days later I get a call again... utility insists it's not their problem... lights are now dim and not going back to normal, ac unit not working. I said "Don't touch anything, I'll be right there!"

(This was a 2-gang meter)
Tested the "Line" side to neutral in the center compartment = OK
Tested the "Line" side to neutral in meter #1 = Not ok!?

...then I heard arcing!... (Remember, This was a 2-gang meter) The loose connection was in the factory assembled parts of the neutral bar in the meter can. If you have ever seen a 2-gang meter you can picture the flat bars that extend from the center out to both meter sockets.
I Replaced the 2-gang meter base on my 4th visit & the problem was solved! :smile:
 
The open neutral will not show as a bad voltage without a load. The easiest way for the PoCo to check this is with a "Beast" as shown below.

arnettsuperbeast.jpg
 
Busman, I've seen one of those in action. Very cool.
It's a wonder they don't bill the customer for all the KWs it draws! :D
 
I got to use one about a year ago. Customer had an open neutral and the lights would dim when he started the washing machine. The lineman showed up with this gizmo I'd never seen before (the super beast). He confirmed the bad neutral and said that since he was working alone, would I mind working the machine to check that his fix solved the problem. He gaffed up the pole and crimped a jumper on the neutral and I checked the load. Very cool device that plugs right into the meter socket.

Mark
 
monkey said:
This is the key.
Click to expand...

I've had to troubleshoot this exact problem. The utility co in my area will typically deny any problems on their end so they can avoid liability to any damages that the homeowner has due to the loose neutral. A good way to check a utility loose neutral is to plug in an electric drill ( or any small motor ) while your meter is attached at the service. Pull the trigger on the drill and you can watch the voltage jump up and down on your meter. Also you can figure out which neighbors are being fed from the same transformer and ask them if they have had similar problems. More than likely they have.
 
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