Lighting issue/Sporadic dimming

Jack A. Trades

Hello all.

Please assist me in diagnosing a lighting issue.
I have a candelabra-type fixture that dims for about 5 seconds and then returns to full brightness.
This occurs sporadically while the fixture is on.
My question is this- is something else turning on and drawing power from the same circuit and causing the light to dim? Can arcing amongst loose wires cause this sporadic dimming?
I don't believe there are any large appliances or other amp-hogs on the same circuit.
However, I'm in Florida, and the house is in North Carolina, so I can't easily troubleshoot it from here. I was just pondering what might cause this. Thanks.

NAIL

How about the refrigerator cycling on randomly. It is also possible a large load on a different circuit is dropping the whole phase. Or it is weak leg coming in from the utility.

Hire a contractor tighten all connections, both meter socket and panel.

elkangorito

What kind of dimmer is it? Leading Edge, Trailing Edge (both electronic) or resistive/inductive? What is the voltage/power rating of the dimmer?
What kind of lamps are used, how many of them are there & what are their sizes (Wattage)?
Are there any other electrical "oddities" happening in the house?

__________________
Switchboard design engineer & Licensed Electrician (Australia).

Jack A. Trades

There is no dimmer- just an on/off switch. The light is randomly dimming.
Its got probably 4 40 watt bulbs.
I think there must be something else on that circuit that is stealing the voltage.

elkangorito

Sorry...I failed to read your initial post correctly.

Please EXACTLY describe this dimming. Does the lighting fixture remain dimmed for many seconds/minutes or does it dim for parts of a second. What is the frequency of the dimming?

__________________
Switchboard design engineer & Licensed Electrician (Australia).

Jack A. Trades

The dimming occurs for less than 5 seconds at a time and occurs sporadically throughout the day. Sometimes it happens 3 times/minute, other times it doesn't dim for hours at a time.

220/221

Dimming lights need to be addressed. Arcs = sparks and sparks = heat and heat = fire.

If it is ONLY the one fixture, start at the switch and look for bad/loose connections. Just spend 50 cents and replace the switch to be sure. There is a good chance that this will fix it.

If not, check the connections under the canopy. It's a common place for a loose connection.

Next, check the circuit breaker and neutral connection.

After that you have to chase it back to the source thru all the switch and recep boxes.

lanispet

Is the house on city water/sewer, or no? The frequency/duration sounds like a well pump drawing the current.

Piedmont

My father had something similar happening. For him it was a faulty breaker. As a warning when he turned off the breaker it looked to have shut off but it DID NOT!!! After turning it off and verifying he couldn't turn on/off the chandelier he started futzing with the wires to the light, but was surprised my mother was still watching TV which he knew was on the same circuit. How tripping the breaker would cause the chandelier to stop working, but TV to continue is a mystery but nonetheless the circuit he was working on was STILL LIVE!

He repeatedly snapped the breaker on/off but it didn't stop power to the TV so he got a new breaker, shut off the main and replaced it and then no more randomly dimming light (and coincidentally it too only affected his chandelier nothing else on the circuit) and when he shut it off afterward everything on the circuit shut off like they were supposed to. Shows the importance of a tester!