Any electricians in the house?

Factual Questions
1

So I come home from work today and find two digital clocks blinking, one in the bedroom and one in the kitchen. OK, must have had a power interruption.

Then, I go downstairs and find the brightness level to be at around 25% of normal. I have three florescent fixtures, each holding four 40-watt bulbs. Each of the 12 bulbs is flickering dimly.

I try a few random replacements (in pairs) with new bulbs to no effect.

I’m already stumped. Perhaps a power interruption followed by a power surge? Maybe my fixtures (all three??) are damaged?

Anyone know how to proceed?

Everything else in the house appears normal.

Thanks!
mmm

2

you should measure the voltage of a number of circuits. you want to get values for each leg of the power coming in your house.

a poor or intermittent connection in your house or from the utility could cause stuff like this.

it is something that should be looked at soon.

unplug and don’t use expensive electronics until you fix the problem.

3

Sounds like a connection in the circuit breaker box may be loose.

Are the two receptacles and the lights on the same circuit? If so, check the connections for that circuit inside the circuit breaker box. This would include the hot wire (connected to the circuit breaker), the neutral wire (connected to the neutral/ground bus bar), and the seating of the circuit breaker itself. Also cycle the circuit breaker a few times to see if that resolves it. (If it does, replace the breaker anyway.) If everything in the circuit breaker box is fine, you’ll have to start pulling receptacles and looking at connections. If you’re uncomfortable doing this, hire it out. Or at least have a buddy do it who is well versed in this stuff.

If they are on different circuits – but on the same phase – it’s probably a connection problem with one of the mains inside the circuit breaker box.

If they are on different circuits and different phases, it’s probably the main center tap (neutral) connection with one of the mains inside the circuit breaker box.

It should also be noted that the problem could be occurring in the meter box or at the transformer.

As stated by johnpost, you need to look into this ASAP. Because if it is a loose connection, arcing could be occurring, which is… not a good thing.

4

Thanks for the responses.

The three light fixtures are on a separate circuit than the two clocks that were blinking. I flicked the circuit breaker a few times, no go.

All the other lights and outlets on that circuit appear to be working fine.

Is it possible that a power surge somehow damaged the three fluorescent fixtures? Maybe fried the ballasts?
mmm

5

I doubt a power surge would be the problem. I would check the voltage before doing anything else. It is possible you had a power outage and when it came back on it may have been under voltage.

6

there are a couple of things you need to be aware of. you have 2 lines coming into your house (not to be confused with 2 different circuit breakers). Each of these lines are 120 volts. So you have 2 sets of 120 volt lines in your circuit breaker box. When you combine these with a dual circuit breaker you get 240V.

You need to check the voltage of both these lines coming into your house. One or both could be lower due to a lighting strike or failure in the transformer feeding your house. If you’re not comfortable checking the voltage have someone do it for you but the easiest way is to check a 240V outlet.

It’s important that both these lines register the correct voltage or you’ll start damaging stuff in your house such as furnace fan motors or compressors.

7

This may be a dumb question, but have you checked with your neighbours to see if they have the same problem?
I get low light levels on fluorescent lights here when a transformer blows up, which is not an unusual situation where I live.

8

And when measuring voltage, make sure there is some kind of load on the circuit; even a nightlight plugged into an outlet will suffice.

9

I know about the two lines. But if one was wonky, wouldn’t other lights/outlets, like half the house, be acting up?

I have other fluorescents that are behaving normally.
mmm

10

Do you have other florescents on the same line as the wonky ones? Also, are the wonky ones and the normal ones the same type of florescent bulb? Maybe one type is more sensitive to an undervoltage. Measuring the voltage on the circuit would be the most straightforward way to clear up whether there’s a voltage problem or not.

Anecdote time: one of our two lines at work got cut a year or two ago. The only sign we had in our office was that one of my two LCD monitors went black. I thought it was just that monitor until I went down the hall and other offices were in the dark.