Technical FAQs

Ask a Question

A circuit breaker, panel, or switchboard seems to be making excessive noise

Product Line:
Circuit breakers

Resolution:
Operational noise has been a question for a long time and it is almost always a stacking up of factors which by themselves go unnoticed, but which together are noticed. 

The attached product data bulletin contains the following information: 

If excessive noise is detected, inspect the equipment for the following: 
• Loose bolts, current transformer mounting, doors, covers and similar 
parts can resonate with the normal 60-cycle hum and cause excessive 
noise/humming. 
• Extra hardware laying in equipment channels and similar type areas can 
cause excessive noise/humming. 
• Open current transformers or improper wiring can cause excessive 
noise/humming. 
OPERATIONS If the equipment inspection does not identify the cause, there are internal 
components inside the circuit breaker that can affect the noise generated 
while the circuit breaker is carrying current. 

Square D has investigated several instances of 
reported excessive noise/humming. In most of these instances, loose 
hardware, wiring, and current transformers have been found to be the 
cause. In the few instances that this was not the case, the circuit breakers 
were evaluated and found to have acceptable performance and service life. 

CONCLUSION No evidence has been found to indicate that operational noise/humming is 
detrimental to the performance or service life of the circuit breaker. 
Was this helpful?
What can we do to improve the information ?