Power fluctuation

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upland

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I'm GC on my own renovation job and have been through 2 electricians and POCO on a problem with no resolution. Thought the great minds here might be able to give me some thoughts on where to point the next electrician or POCO.

Problem: All lights and appliances dim/loose some power when others are operated. Any power draw on any circuit causes fluctuation on all others. Lights pulsate to the washer motor, interior/exterior lights dim when the 1/4 hp sump pumps kick on. Toaster dims the range hood motor.


Back ground: Condition may have existed prior to purchase of property. Since purchase, 90% of the wiring is new, last 10% will be soon. New garage and kitchen additions all code, no shared circuits (recps and lighting separate). Biggest draws are 4 tn heating/cooling, 80gal water heater. Kitchen is gas. Few dozen recessed lights on dimmers.

All neutrals are tight at panel and branch circuits and appliances. All lighting circuits and receptacles work normally. (2) shared neutrals in old wiring but they were pulled and still no change in condition.

POCO replaced over head neutral due to tree rat damage and it appeared to resolve problem for a breif period. (Maybe it was just an illusion). Since return of problem, they have checked twice and declared power to both leg fine.


What isn't being looked at? What should be tested next? What are the code words that POCO responds to? Thanks.
 
We do not allow Do-It-Yourself questions on this forum. But I perceive this to be a different type of situation, as the OP is not attempting to do the electrical work himself. So I will allow it to remain.

The symptoms you are describing have "loose neutral" written all over them. But since your electricians haven't found one yet, I can only offer one suggestion. Have the electrician attempt to isolate the problem to the one (or possibly more) circuits that is (are) giving the symptoms. Do that by first turning off one breaker at a time, and see if the problem goes away. If that does not isolate the problem, then turn on one circuit at a time until the problem appears. If that does isolate the problem to that one circuit, then turn it off, and continue turning others on one at a time, to see of a second circuit also causes the symptoms. The final step would be to trace out, or simply replace, the wiring in the offending circuit(s).
 
All circuits have (previously) been switched off and corresponding neutrals pulled one at a time. Under the impression that turning off breaker alone won't isolate neutral problem, particularly when all circuits are involved and no one specific circuit presents as problematic from an operational stand point.

Will ask next electrician to verify meter socket.

Thanks.
 
charlie b said:
The symptoms you are describing have "loose neutral" written all over them.
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Maybe yes, maybe no. If any circuits exhibit a voltage rise, such as brightening or speeding up, then absolutely yes. If it's all voltage drops, it's one or both line conductors (or all three.)

If any of the loads are affecting circuits other then their own, the problem is definitely at or before the panel, indicating service or utility problems. Anything before the POA is the utility's responsibility.

Measuring voltages during surges is a way to determine the origin of the voltage drops. I'd try the panel main terminals first, then the outside main if there is one, and then at the POA.

Ask neighbors sharing the same utility transformer if they're having similar issues. It could simply be the transformer is no longer large enough for the supplied houses' current needs (pun intended.)
 
I agree with larry. You said that when poco replaced the overhead neatral the problem was resolved. How long did it last? Did poco find damage on that conductor and why did they not replace all the wires ? Poco like lots of other companys , to save money by doing as little as possible to solve the problem . I was called to an apartment building once with no power. I noticed the 400 amp fuses were blown. Poco was called earlier and they told the owner that it wasnt anything to do with them. The problem ended up being one of the digital meters was damaged and you could physically see the damage but they missed it. I would call poco to come back out have your electrician out there to at the same time to investigate further.
 
Without proper tools you are hunting for a needle in a haystack! If what you posted is truely happening RE: "ALL" the lights are flickering--your problem is on the wire that is common to "ALL" the lights that are "flickering". That wire is the nuetral. Not knowing the service layout it is impossible to determine the probable location. Hire a licensed contractor who owns a data logger, a tool that measures everything that is happening on the circuit you connect it to. If he installs it on the main service first, it will tell him which way to hunt for the problem. If the problem went away after the power company worked on their system, i would suspect a neutral problem in the service. And if it is on the power company's side they will require proof which you can hand them from the information gathered by the power monitor.
 
upland said:
Problem: All lights and appliances dim/loose some power when others are operated...........POCO replaced over head neutral
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The fact that all lights are dimming without some brightening indicates it is not a neutral problem. However, since some service work has recently been completed, my first guess is that the lugs are not properly torqued. It is mechanics-101, always go back and re-torque fasteners after a short usage.
 
090528-2058 EST

upland:

Some simple experiments you can run.

Required equipment:

Two small incandescent lamps with the same wattage. I suggest 15 or 25 W because this is a size that is easier to look at directly.

A variety of extension cords.

A 1500 W portable heater. At full power this will provide about 12 A load at 120 V.

Personally I can see the intensity change of an incandescent lamp from a 1 to 2 V supply change at a nominal 120 V. I believe most people can see a change in intensity from a voltage change of 3 to 4 V.

The following experiments do not require entry into any electrical box.

I will assume that all circuits come directly from the main panel, meaning there are no sub-panels.

First, find two different receptacles such that they are on the two different phases. Try to find circuits that do not have other changing loads on the circuits.

Second, connect one lamp to one phase and the other lamp to the other phase. Set the lamps side by side, and remove any shades.

If the two lamps are not of equal brightness when the heater is off, then try to shed all loads on the main panel except for the two bulbs.

Third, connect the 1500 W heater to one of the outlets.

Fourth, turn the heater on and off.
The lamp on the same outlet as the heater should dim when the heater is on.

Here I assume that the neutrals of the two out of phase branch circuits do not connect together until they are terminated on the neutral bus in the main panel.

What happens to the other light?

If it brightens, then it indicates a voltage drop on the neutral from the transformer. The magnitude of dimming and brightening is in part an indication of the amount of voltage drop on the neutral.

If there is a great deal of dimming on the one lamp and brightening on the other, then there is a significant neutral problem.

I have very low impedance wiring from my main panel to my pole transformer. I also have outlets on both phases at the main panel. Using the two bulb test and a 1500 W heater I get a 1 V change from turning the heater on. The majority of this is from the transformer impedance. I did not perceive a difference in intensity of the two lamps with and without the heater load.

I added a short extension cord to the phase with the light and heater. This gave me a 3 V drop at the bulb when the heater was turned on. This change in voltage was noticeable. No change in the bulb on the opposite phase from the heater.

From what you have described I expect you have voltage drop of a noticeable amount on all three wires supplying your home. The above test will tell us more.

How long in feet is the run from your meter to your power company transformer?

.
 
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