Flickering Lights

[bayfarmer]

Indoor spot lights on two circuits flicker. Problem began at the same time on both circuits. Both circuits feed areas of the house that were remodeled in 2001 so electric wiring, fixtures, outlets, and circuits are less than ten years old.

What's up?

[HayZee518]

are the spots mounted on a track?

[bayfarmer]

No, the lights are in individual can light fixtures. Also, flickering may the the wrong term. It is more like a surge where the light gets brighter for a moment and then resume regular output. Also, all lights do not do it at the same time. You can see one get brighter. Then while you are watching that light to see if it will do it again, another one does the same thing. If it were a single light, I would check the wiring. If they all did it at the same time, I would change out the breaker.

[HayZee518]

No need to change out the breaker. Are the lights on a dimmer? If they are, the dimmer changes the AC to what they call "chopped" DC.

[bayfarmer]

No, the lights are not on a dimmers. They are controlled by regular switches. There are a total of eighteen bulbs controlled by seven separate switches.

sw-1 1 bulb
sw-2 2 bulbs
sw-3 3 bulbs
sw-4 5 bulbs
sw-5 2 bulbs
sw-6 4 bulbs
sw-7 1 bulb

I would suspect small power surges in the electric supply but the effect is not present in the older part of the house.

[HayZee518]

OK, then what I would look for is a loose neutral somewhere in the fixture line. because all lights use a common neutral and at least two or three hots are only connected to black. the other thing may be the thermal overload that is integral to each fixture. what's the wattage per lamp?

[bayfarmer]

wattage varies between 16 and 70.

[HayZee518]

I never heard of a 16 watt bulb! are these "spots" low voltage? say 12 or 24 volt?

[bayfarmer]

The 16 watt bulb is one of the new high efficiency bulbs. There is no low voltage supply for any of the lights.

[HayZee518]

ok, I spotted a cfl 16 watt par 30 bulb. it operates at 120 volt. because yours is mounted base up in a can fixture, the electronics are subjected to all the heat the bulb generates. this heat weakens the life of the bulb. all cfl's are "gas discharge" bulbs and operate at a higher than 120 volts inside the bulb as they arc across an electrode in an atmosphere of mercury vapor. what creates the light is the inside coating as it "phosphors" or glows. Off hand I'd say your bulbs are on the way to fail. change the bulbs to a regular 60 or 75 watt par 30 reflector spot and your pulsating bulbs won't pulsate.