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| Subject - Buzz at Service Panel | |
| akopperl |
I recently purchased a new amp for my home theater and began hearing a buzz from my front right and left channels (I did not notice this buzz with the receiver I owned previously - but I did not notice it when I first installed the new amp either - that doesn't mean it wasn't there). I thought that I was suffering from a ground loop and began to diagnose. I disconnected everything from the amp, but the speakers and the buzz was still there. I put a cheater plug on the amp - just as a temporary test figuring that would remove the buzz - but the buzz was still there. My conclusion after doing all of this was that the amp was defective. However, while I was doing all of this testing with the amp it popped the breaker several times. At first, I didn't think much of it. It is a fairly large amp and despite it being on a 20 amp dedicated line (there are 3 separate 20 amp lines in the room) - I figured the inrush of current could cause this. When I went to the service panel to flip the breaker, I heard a buzzing from my service panel (I can't isolate the buzz to the circuit breaker in question). Previously, I had never heard this buzz, but I don't go to the service panel often. The buzz is very similar in sound to what I hear from my speakers. First of all, why is my panel buzzing - I'm assuming that it is a problem and needs to be fixed (my house is still under warranty - 6 months old)? Can this buzz be causing my amp problems - can the amp possibly be picking up the buzz and amplifying it through my speakers? Thanks |
| JimmyDee | There is no way your amp should be tripping a 20 amp breaker. The buzzing could be the large current draw, trying to pull in the magnetic trip part of the breaker. You need to get a clamp on amp meter and check out the amp draw on the amp. I'll bet you will find it defective. Usually the buzzing comes from a bad filter cap in the power supply. I have a feeling it is shorted or bad and that is your problem. Jim |
| akopperl | Thanks for the reply. The service panel buzzes even without the amp or any other item plugged into the outlet. Any reason for why the service panel is buzzing? |
| kbsparky | Your buzzing can be one or more of the following: 1) Transformer connected to the panel, like for a doorbell. 2) One or more of the circuit breakers can buzz under load 3) Even the main breaker can do this. 4) AFI breakers have power supplies in them, that may buzz 5) Loose connection(s) on one or more breakers I've found that Cutler-Hammer breakers are more likely to buzz than other brands. What brand is your panel 
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| akopperl | The panel and breakers are made by Square D. I'm assuming it makes sense to have an electrician check it out? I actually emailed the designer of my amp and he wasn't sure what the problem was - but represented that it is not unusual for the amp to pop the circuit breaker upon initial power up. That never happened before with the prior 2 amps I owned. Although with the prior receiver I owned, I received a message several times telling me there was a brownout and it shut itself down. I don't know whether that sheds any further light on my situation. The receiver was plugged into the same outlet that the amp is currently using. Thanks |
| kbsparky | quote: Persactly. You might want to have an electrician check out that main breaker. Especially since the one incident reported "brown out" conditions, which can be an indicator of a loose internal connection in that main breaker. How old is your Square D panel? Is it a QO type, or Homeline Be sure to have someone check to see if there is any voltage difference between the line and load sides of that main -- when buzzing for sure. They might want to do a load test, by switching on such things as your water heater, range, dryer, A/C etc (assuming those appliances are electric). Good luck, and let us know how things went 
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| akopperl | The electrician came and informed me that the arc fault breakers (blue switch on breaker) in my panel from Square D had been recalled. Apparently, these breakers are causing certain electrical appliances (such as vacuums) and equipment to trip unnecessarily. He replaced 3 of them with new arc fault breakers (green switch). I have 8 in all so he is coming back tomorrow to replace the remaining 5. The buzz is still present. He checked all of the connections and actually found 2 breakers where the wires wern't properly screwed down. He is hoping that after swapping out the remaining 5 arc fault breakers that the buzz will go away. If not, they may swap out the entire panel. However, when I called to schedule the next visit one of the phone guys told me that some of these new arc fault breakers buzz and nothing can be done about it. He didn't seem to think that they would replace the panel. Does this make any sense or should I insist on swapping out the panel? Thanks |
| kbsparky | Does it still buzz when you switch off all those Arc-Fault breakers |
| akopperl | I wasn't close enough to the panel when the electrician was working to hear if there was a buzz. He never shut them all off at once - just one at a time. As he shut off each one individually, he listened and said that he could still hear the buzz. Thanks |
| akopperl | Interestingly enough - apparently Surge D Arc Fault Breakers are supposed to hum: http://www.squared.com/us/products/motor_control.nsf/unid/DB9C2F2BDABA3AF485256C2200692460/$file/faqFrameset.htm The electrician finished replacing out the recalled breakers and at this point I think/hope everyhting is ok. Thanks |
| wandering sparky | I seem to remember that some of the older Square D panels would buzz because of how the guts were mounted. If they were not torqued down , any vibration or hum would be amplified by the panel can. Sounds like your electrician should check all the connections , especially the main breaker , as well as see if all is "tight and right". Beyond that, an old breaker may just be singing it's swan song. In which case , its time to change out that breaker. Arc-faults and gfci will humm sometimes, but not so loud you would normally notice. Also , low voltage lighting transformers and fluoresent lights will sometimes cause a humm in audio equipment. But your electrican is going to have to judge that. There can be so many variables that it would just have to be looked at by qualified electrician.
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