What could be causing this electrical issue?

Question

The problem occurs within one particular unit of an apartment complex. All other units are fine. The problem has gradually gotten worse. All electricity within the house will flicker on and off. It is most obvious with the lights but TVs, stove, and other appliances are affected as well.

At first, this would only be triggered when using a lot of electricity (ie microwave, space heater, several things at once), but now it seems to happen at random times. The tenant even gave me a scenario of when he woke up early one morning to use the bathroom and it happened as soon as he turned on the bathroom light. No one else was up and therefore minimal electricity was being used at the time.

I have had PGE come out to look at the problem and its not their end. They also told me that because it's happening to the entire unit at the same time, it most likely is a problem somewhere from the main box outside to the box inside the unit and specifically the neutral line. When he took measurements from the individual breakers inside the unit and measurements would be as high as 160ish in some parts while 40ish in others. You can also see this in the ceiling lights (unusually bright in the kitchen and unusually dim in the bathroom). This problem has also damaged several appliances and things within the house (dvr recievers, dvd players, etc).

Any suggestions? The electrician located the neutral line in the junction box. No damage or charring and the connection was still tight. He looked in the main panel outside - minimal corrosion, still tight. He added some paste to maximize conductance and that was it. The breakers inside are fine. He even opened up most of the wall switches and outlets to investigate but found nothing. Any ideas? This is a problem that has kept me up for about a month. I'm afraid of it being a fire hazard too.

Answer 1

If you are the landlord I would have another electrician come out to check it. It be something like a factory defect in the subpanel or main panel. Every lug could be tightened and torqued to factory specs but the lug might be stripped out.

If you are the renter then I would make it clear to your landlord that this is a serious problem and you want if fixed now.

Which ever you are I would have every lug on the ground, neutral and hot sides torqued down to factory specs. Get the electrician to do a thermal reading while the panel is hot and having the problem. This would surely cause extra heat where ever it is happening. If the electrician does that and nothing changes have PGE torque everything on their end and do the thermal reading.

I had the same problem and when they removed the meter and left I removed the Edison side covers and one of the lugs was never tightened on their end but it was a factory connection that was the problem.

Edit On questions on what to use to torque a circuit breaker, see this. Each breaker has a label on it with the torque rating on it. At one time there was talk of inspectors carrying torque wrenches with them to spot check circuit breakers, but I know of no electricians own a torque wrench. When I ask they say just tighten them down as hard as you can and they will pass any test. My guess is that most residential breakers use about 20 to 25 foot inch lbs per square inch.

Most of the time torquing happens is in industrial plants where they want to get the maximum life out of everything, including breakers. This is also why thermal cameras are sold to electricians. Heat spots are bad and most of the time it is a loose connection.

In the OP's case I would definitely use the phrase Torque to specifications, especially if he puts any thing in writing. His problem can wreak havoc on electronics and motors.

Answer 2

There might be a break in the wire from the meter to the main panel. The break is small enough to work most of the time but under a large load it will increase in resistance. Or a big truck passing by may shake the ground enough to widen the crack. Try having that piece replaced.

Second to that, I would replace the main breaker for the same reason.

Answer 3

I would consider hiring a thermal imaging camera. Given what you have probably spent already, and the danger posed, you may want to invest in one that attaches to your Android or Apple smart phone. You can always sell it afterwards. In the UK, a 3 day hire is around $100.

I'd be inclined to look at the main breaker. View that with the camera and get someone to turn lights / appliances off and on. Try to trace the physical route of the main cable from outside, even if it's concealed, and do the same as above.

I don't wish to alarm but it is a potential fire hazard. If for example, a rodent has chewed a concealed cable, bad news as that could cause a fire. On the other hand, if the problem is inside a breaker, it is less likely that would cause a fire as they are made and usually fitted inside non-combustible materials.