Amp tripping circuit breaker.


I have a 20 amp circuit, AFCI breaker, with only my entertainment rack on it.  The breaker has been tripping periodically for about a year now.  Recently the problem has been worse and I suspected my amplifier.  Long story short, the breaker only trips when the amp is plugged in, with statistical certainty.  Unknown if it matters if amp is on or not.

Amp is a Monolith 7.  I opened the cover and saw no obvious signs of damage.  Everything is clean and dust free.

any thoughts?
magneplanman
NEVER change 2 things at once.

Ground at wall outlet?

I can understand lost confidence in the amp, but, the advice to replace the breaker first is the best.

If electrician does it, he/she can also test ground, at the panel and at the wall outlet.

That will tell you whether it was the ground, breaker, or the amp.

IF, after replacing breaker, ground confirmed, with amp connected, turned off, new breaker trips, curious indeed. Test that before electrician leaves.

Do you have any other equip you could substitute for amp, to see if problem goes away? 

IOW, think like an electrician rather than as an audiophile.

New amp after circuit confirmation? Always fun. Keep in mind, you won't be able to sell the existing amp unless you confirm it was the breaker, not the amp. Another reason not to change two things at once.


I had the same thing happen, but only with a particular high current amp. Other more modest amps would not trip the breaker. But if I plugged the high current amp in any other circuit it would not trip a breaker.

I haven't done so yet, but replacing the breaker is on my to do list.
magneplanman OP4 posts

12-10-2019
11:44am

One thing I forgot to mention - the reason I suspected the amp is because it’s own protection was tripping earlier in the summer, often immediately when powering from a cold start. It ended up going away. Only thing I can think of that made the problem go away, was I went from having the thermostat set at 76 to 72, which definitely reduced the indoor humidity.

Repeat:
One thing I forgot to mention - the reason I suspected the amp is because it’s own protection was tripping earlier in the summer, often immediately when powering from a cold start.
@ magneplanman

I assume you are referring to the 15 amp "Master Power" On-Off/circuit breaker on the rear panel of the amp. Is that correct? The "Master Power" circuit breaker was tripping immediately when powering from a cold start?

See page 6 of manual.
E. MASTER POWER:The Master Power switch is used to apply or remove power to the amplifier. By contrast, the Power switch on the front panel is used to switch the amplifier between standby mode and full power on.
See page 10.
MAIN CIRCUIT BREAKER: The Master Power switch on the rear panel doubles as a circuit breaker. If the circuit breaker trips into the off position, try flipping it back on. If it immediately trips back off, unplug the amplifier from the power source and have it serviced.
https://downloads.monoprice.com/files/manuals/14566_Manual_160414.pdf

One thing I forgot to mention - the reason I suspected the amp is because it’s own protection was tripping earlier in the summer, often immediately when powering from a cold start. It ended up going away.

"It ended up going away. "

As in the breaker no longer works?


Please respond if the above circuit breaker was the device tripping immediately on a cold start up of the amp.I also would like you to move the "Main Circuit Breaker" (rear panel on the amp) to the off (O) position. Verify in the off position the unit is dead, no power, lights, ect...

As for the dedicated branch circuit GFCI breaker that feeds the amp. Going from what you posted it was/is high inrush current draw from the amp that was causing the 15 amp breaker at the amp to trip open. Assumption, the breaker no longer works. The GFCI breaker was next in line to protect the branch circuit wiring. (You never mentioned what manufacturer the electrical panel/breaker is. It would be nice to know) Note. It would be safe to say it is the Thermal-magnetic section of the AFCI breaker that is causing the breaker to trip open. The high inrush current draw of the amp is causing the breaker to trip open.

Is the AFCI breaker weaker now after several tripping events than when it was when it first tripped opened? Probably. Will installing a new breaker solve your tripping problem? For a while. Band-aid repair.

.
jetter1,477 posts   

12-11-2019  
 8:03am  

I had the same thing happen, but only with a particular high current amp. Other more modest amps would not trip the breaker. But if I plugged the high current amp in any other circuit it would not trip a breaker.

I haven’t done so yet, but replacing the breaker is on my to do list.
@jetter

In your case you may want to see if the manufacturer of your electrical panel makes a High Magnetic, HM, branch circuit breaker.


What is a HM type breaker? What does it do? It allows a greater lag time for inrush current before it will trip.

Example of:

Square D

Standard QO115 and QO120 circuit breakers are manufactured to have a magnetic trip point at approximately 8x to 10x the breaker rating. There are some applications, however, in which a load has an inrush current high enough to cause these standard circuit breakers to trip. Examples of these loads include area lighting for athletic fields, parking lots, or outdoor signs. To allow the high inrush current without tripping the circuit breaker, a high magnetic breaker should be used. These high magnetic breakers breakers have a magnetic trip point set much higher than the standard circuit breakers. They can be identified by the HM suffix on the catalog number (QO115HM). Current production HM breakers are also identified with a "High Magnetic" label on the side of the breaker (see photo).
NOTE: The above explanation comparing the standard breaker to the high magnetic breaker applies to 1-pole, 15A and 20A, QO, QOB, QOU, HOM and CHOM breakers only. Other ampere 1p breakers, and all 2-pole and 3-pole versions are already high magnetic as standard. (Breakers with suffix GFI, AFI, CAFI, or DF are not available as high magnetic).
https://www.se.com/us/en/faqs/FA96714/


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Thanks for the information jea48, live and learn.  I will talk to my electrician about it.  I know changing a breaker is a simple thing, but I would rather not mess around with it myself.

I do know that when a friend was going to replace the breaker in question, for some reason it was not one of cheaper ones that GE makes.  It had something about it that made it a $50+/- variant.