Buzzing breaker

Status
Not open for further replies.
augie47

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
E/C called & asked advice.
His customer has a new home and the breaker supplying the dishwasher circuit a constant noise described as a hum or buzz. Swapped breaker and location and problem remained.
Current draw is 2 amps.
Any idea ?
 
augie47 said:
E/C called & asked advice.
His customer has a new home and the breaker supplying the dishwasher circuit a constant noise described as a hum or buzz. Swapped breaker and location and problem remained.
Current draw is 2 amps.
Any idea ?
Click to expand...
Is the breaker AFCI or GFCI?
There is a fair chance that the hum is coming from the wire itself and being conducted to the breaker, or the ear is just not detecting that the source is the branch wiring.
At 2A it is unlikely that mechanical forces between wires are causing the wires to vibrate, but some sort of arcing fault in the branch might have that effect.
The current draw could be only 2A but have a really large high frequency component resulting from a fault.
If the dishwasher is cord and plug connected, pull the plug and maybe plug in an equivalent sized heater load.
If it is hard wired, noise generated in the DW itself might be coming down the raceway. (Forget that idea if NM is being used, unless it is stretched very tight. :))
 
augie47 said:
E/C called & asked advice.
His customer has a new home and the breaker supplying the dishwasher circuit a constant noise described as a hum or buzz. Swapped breaker and location and problem remained.
Current draw is 2 amps.
Any idea ?
Click to expand...
More details on the dishwasher may be necessary. How much chance is there it has solid state high speed switching on a motor or heater control component? Are you measuring your 2 amps with a true RMS meter?

Is it a GFCI, AFCI, or combination of both type of breaker?
 
augie47 said:
E/C called & asked advice.
His customer has a new home and the breaker supplying the dishwasher circuit a constant noise described as a hum or buzz. Swapped breaker and location and problem remained.
Current draw is 2 amps.
Any idea ?
Click to expand...

Arc-fault breakers can buzz slightly during normal operation. It took me a while to get used to it.
 
Augies is the buzzing noise still there when you took the dishwasher off the line


In belief, man can do anything
 
The "buzz" is only there with the dw operating. 2 amps was the load measured at that stage of the unit running.
 
"operating " hmmm

the duration of the buzz is long or short?
where is the panel anyway - how remote from the dw?
whats the wiring method?
any photos? of breaker and load

the buzz goes away when what changes at the dw? changes cycle
 
What components of the DW are running at the time, and is there solid state switching devices directly controlling the load, good candidate for what I am getting at here would be a ECM motor which is popular in front load clothes washers but wouldn't be surprised if you are seeing them in dishwashers.
 
Status
Not open for further replies.
Top