Lighting system causes buzz in circuit breaker panels when dimmed

[Mike Caldwell]

At an install where I put in the sound system their lighting system causes buzz in portions of the system when dimmed. Pin one lifts, isolation transformers do not help at all. When checking all the outlets for proper wiring I noticed a considerable amount of buzz coming from the the main breaker panel and the sub panel feeding the lighting circuits. When the lights are full up there is no buzz at the breaker panels or in the system. They have four NSI dimmer packs all on separate circuits. The building was a machine shop and has a three phase power service, not sure how the lighting circuits are divided between the phases.

Any ideas!

 

[Gene Hardage]

Re: Lighting system causes buzz in circuit breaker panels when dimmed

At an install where I put in the sound system their lighting system causes buzz in portions of the system when dimmed. Pin one lifts, isolation transformers do not help at all. When checking all the outlets for proper wiring I noticed a considerable amount of buzz coming from the the main breaker panel and the sub panel feeding the lighting circuits. When the lights are full up there is no buzz at the breaker panels or in the system. They have four NSI dimmer packs all on separate circuits. The building was a machine shop and has a three phase power service, not sure how the lighting circuits are divided between the phases.

Any ideas!

A lot of the old school dimmer style lighting buzzes. The short answer is scrap it all and start over with some LEDs or at least something that was designed in this decade. Years ago a friend tried to explain something about cheap dimmers emanating some kind of noise that could be filtered out with the addition of choke coils. I've never looked into it and there are probably people here that can tell you if it's a cost effective fix or a waste of time and money.