I upgraded a service to a 200 amp the other day(new panel, breakers, meter, wire , the works) and noticed that one of the breakers when on had a high pitched hum to it at times. I tried changing the breaker that did not fix it. I did notice that it would only occasionaly hum. The circuit was general lights and a computer(no a/c or anything like that) Nobody was home at the time so nothing was being used on and off so that I could compare what was being used to when it was humming. Also the hum was not loud at all. I probably only heard it because I was the only one in the home. The house is an old home as well, some knob and tube remaining. I have heard some humming before in commercial applications but I never have noticed it in residential. Does anyone have a clue what it is?
High pitched humming?
- Thread starter ram11379
- Start date
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kkwong
Senior Member
- Location
- Sac, CA (I think)
I would check your neutrals as it might be a load inbalance. Other then that, maybe try to sched when you can make entry with the HO and diagnose the affected circut and ensure proper connections.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
And to think I restrained myself.H.L. said:
e57
Senior Member
- Location
- San Francisco, CA
Break out that stethescope. If from the breaker - I would say 1 of 2 things: Loose connection to or from it, or the thermals.
Did you add any other breakers? Like say an AFCI? The electronics in those can be noisey.
Did you add any other breakers? Like say an AFCI? The electronics in those can be noisey.
cadpoint
Senior Member
- Location
- Durham, NC
Did you move that circuit to the other phase and or another breaker position ? That the perfect reason to get one of those HigH Dollor Gizmo's, that makes Pictures, Charts and Graph's. Chip on or bolt down breakers, Did I miss that ... ?
Use a Paper Towel Roll to Ear to Isolate the sound, workes great for other applications too, Motors, Spindals, bearings/gears, yeap she's singing...
The occurance is due to the local radar sweep ....
Use a Paper Towel Roll to Ear to Isolate the sound, workes great for other applications too, Motors, Spindals, bearings/gears, yeap she's singing...
The occurance is due to the local radar sweep ...
.
brian john
Senior Member
- Location
- Leesburg, VA
Did you amp the circuit?
Did the amperage change with load?
As noted sounds like the thermal device in the CB, but usually with two different CB's one would assume at least one of them is OK and thermal operation noise is not usually noticed till you are close to trip time.
Did the amperage change with load?
As noted sounds like the thermal device in the CB, but usually with two different CB's one would assume at least one of them is OK and thermal operation noise is not usually noticed till you are close to trip time.
ghostbuster
Senior Member
- Location
- Great White North
Sometimes the small transformers for the house doorbells etc. are attached to the panel (if the laminations are loose they could make this noise).:smile:
Ok here's a little more info.
The panel is a 200 amp 40 space homeline. It is about half full, all connections in panel are def. tight. The circuit in question is a 20 amp single pole. When I turn it off the noise goes away. If I leave it the noise goes away on its own(even if nobody is around to make any changes to the circuit) but it eventually comes back. I have changed the breaker. The noise actually sounds like it is coming from the main in the panel. I did not try to move it to the other phase. I didn't think of that when I was there and the job is over an hour away in the country. There shouldn't be a phase imbalance though I broke up everything new installed and the original circuits are small with only a dryer and stove as major draw factors. Three is no doorbell transformer on the panel. And I don't have one of those HigH Dollor Gizmo's, that makes Pictures, Charts and Graph's!
The panel is a 200 amp 40 space homeline. It is about half full, all connections in panel are def. tight. The circuit in question is a 20 amp single pole. When I turn it off the noise goes away. If I leave it the noise goes away on its own(even if nobody is around to make any changes to the circuit) but it eventually comes back. I have changed the breaker. The noise actually sounds like it is coming from the main in the panel. I did not try to move it to the other phase. I didn't think of that when I was there and the job is over an hour away in the country. There shouldn't be a phase imbalance though I broke up everything new installed and the original circuits are small with only a dryer and stove as major draw factors. Three is no doorbell transformer on the panel. And I don't have one of those HigH Dollor Gizmo's, that makes Pictures, Charts and Graph's!
ram11379 said:Ok here's a little more info.
The panel is a 200 amp 40 space homeline. It is about half full, all connections in panel are def. tight. The circuit in question is a 20 amp single pole. When I turn it off the noise goes away. If I leave it the noise goes away on its own(even if nobody is around to make any changes to the circuit) but it eventually comes back. I have changed the breaker. The noise actually sounds like it is coming from the main in the panel. I did not try to move it to the other phase. I didn't think of that when I was there and the job is over an hour away in the country. There shouldn't be a phase imbalance though I broke up everything new installed and the original circuits are small with only a dryer and stove as major draw factors. Three is no doorbell transformer on the panel. And I don't have one of those HigH Dollor Gizmo's, that makes Pictures, Charts and Graph's!
When you used your clamp on amp meter, what was the reading on that circuit ?
kbsparky
Senior Member
- Location
- Delmarva, USA
And that was going to be my question to you: Are you sure the noise is coming from a branch circuit breaker?ram11379 said:
I've heard mains do things like that, usually when they are on their last leg, so to speak
Try switching on the burners on an electric range .... turn on the clothes dryer on high heat .... turn up the water heater .... anything to momentarily increase the load to see if you can induce/duplicate the cause of the sound.
If the house has mainly gas appliances listed above, then bring a portable electric heater with you, or use something like a blow dryer, etc. Switch on the toaster, microwave, etc. You get the idea.
You might have to replace that main breaker, a relatively simple task.
Do they have...
Do they have...
From what I highlited above....check to see if they have a laser printer or a home photocopier on that circuit...
My laser printer induces a subtle whine in the UPS under my desk when it cycles the fuser heater. (It's an internal heater that fuses the toner to the paper.)
Or sometimes a SMPS on a computer or even a plasma or LCD TV can induce some weird noises....
Do they have...
ram11379 said:Ok here's a little more info.
The panel is a 200 amp 40 space homeline. It is about half full, all connections in panel are def. tight. The circuit in question is a 20 amp single pole. When I turn it off the noise goes away. If I leave it the noise goes away on its own(even if nobody is around to make any changes to the circuit) but it eventually comes back. I have changed the breaker. The noise actually sounds like it is coming from the main in the panel. I did not try to move it to the other phase. I didn't think of that when I was there and the job is over an hour away in the country. There shouldn't be a phase imbalance though I broke up everything new installed and the original circuits are small with only a dryer and stove as major draw factors. Three is no doorbell transformer on the panel. And I don't have one of those HigH Dollor Gizmo's, that makes Pictures, Charts and Graph's!
From what I highlited above....check to see if they have a laser printer or a home photocopier on that circuit...
My laser printer induces a subtle whine in the UPS under my desk when it cycles the fuser heater. (It's an internal heater that fuses the toner to the paper.)
Or sometimes a SMPS on a computer or even a plasma or LCD TV can induce some weird noises....
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