Light bulbs are constanly burning out

Has someone there measured the line voltage? If not, that would seem to be the logical first step. If the voltage is too high, that would certainly explain the frequent bulb burn-outs, if not the breaker trips, and perhaps the power company could do something about it.

Regards,
-- Al

Can I check the voltage myself with a multimeter? If so how?

Yes. Set the multimeter to read AC Volts, on a scale such as 0 to 300 volts or some such number that will assure it won't be driven past the upper limit of the scale. Make sure that the test leads are connected to the proper jacks on the meter for making an ac voltage measurement on this scale.

WITHOUT TOUCHING THE METAL PROBE PINS AT THE END OF EACH TEST LEAD, insert one lead into one of the two vertical slots on an ac outlet, and the other lead into the other vertical slot. The meter will then indicate the line voltage.

While you are at it, also measure between the shorter vertical slot (which is ac "hot"), and the ac safety ground opening on the outlet (the one that accepts the circular third prong on an ac plug). That should indicate the same voltage as you measured between the hot and neutral terminals.

Then measure between the longer vertical slot (ac neutral) and ac safety ground. That should measure 0 or very close to it.

Then measure between each of the two vertical slots and the screw which holds the faceplate on. You should get the same two readings as when you measured between each of the vertical slots and the ac safety ground prong.

If any of these additional measurements are not correct, it indicates that there is an open connection or a miswire somewhere.

Regards,
-- Al

Nick -- Yes, let's see what it does at other times during the day and night, although higher demand would figure to lower rather than raise the voltage (due to increased losses in the wiring), as you appear to realize. And I'll defer to the comments Jim (Jea48) will most likely offer on the 3 volt offset between neutral and safety ground -- he is more knowledgeable about that kind of thing than I am.

Regards,
-- Al

Nice explanation, Jim. Thanks!

So if he has a 3V differential between ac neutral and ac safety ground at the particular outlet he measured, let's make the following rough assumptions:

-- 100 feet of wiring from the outlet to where those two lines are bonded together at the service panel.

-- Negligible current flowing through the safety ground wiring.

-- Wire resistance of 1.6 ohms per thousand feet (corresponding approximately to 12 gauge wire). Which would mean 0.16 ohms for 100 feet.

That would mean, if the resistance through the path is what it should be, that he has 3/0.16 = 18.75 amps flowing through the neutral wiring on that line.

Sounds kind of high, suggesting that perhaps the resistance is higher than it should be somewhere in the neutral run.

If so, meaning that losses in the hot side of the wiring are small compared to the losses in the neutral run, the voltage at the service panel for that line would be the 124.5 measured at the outlet + 3 = 127.5 volts.

And if not (if connection integrity is good for all of the neutral path between service panel and outlet), there is presumably also a 3V drop in the hot side of the wiring. That would mean that the voltage at the service panel for that line would be the 124.5 measured at the outlet + 3 x 2 = 130.5 volts.

In either case, these numbers provide added credence to the possibility you have suggested.

Does that all sound right?

Regards,
-- Al

The only time the lights dim is when my wife switches on the kettle. The kettle is plugged into the same breaker as the plug that the lights in the main living area are connected to. If I take a reading on that plug the voltage drop is from 123.8 to 110. (measured across both vertical slots). However, if I measure from the short vertical to the ground then it reads 116v. If I turn off the kettle the reading goes back to the 123.8.

Nick -- How many watts does the kettle consume? That should be indicated on a label somewhere on it.

Regards,
-- Al

The only time the lights dim is when my wife switches on the kettle (1500 watts). The kettle is plugged into the same breaker as the plug that the lights in the main living area are connected to. If I take a reading on that plug the voltage drop is from 123.8 to 110. (measured across both vertical slots). However, if I measure from the short vertical to the ground then it reads 116v. If I turn off the kettle the reading goes back to the 123.8.

Jim, it sounds like he's got a bit more than about 1/2 ohm of resistance between the service panel and the outlet, in each of the two runs (hot and neutral). Seems a little high, unless the runs are unusually long.

But in any event, that would mean that all of the voltage readings Nick reported (measured at the outlets) are probably understating the voltages at the service panel, by around 1.1 volts per amp of current draw. And since those measurements are highish to begin with, it sounds like something really is amiss on other side (the outside) of the service panel.

So I agree that a call to the power company definitely seems warranted.

Regards,
-- Al