Nuisance tripping of AFCI circuit breaker by inrush of current when turning on amplifiers

I would definitely start with a second generation Siemens CAFCI breaker.

Im not sure about your situation butI have 20 Siemens CAFCI breakers, all upgrades fron non AFCI and never had a nuisance trip.

The electrician probably can't help you.  What you really need is a soft start on your power supply.  Many large power supplies charge the system through an inductor to limit inrush current and then switch to a straight wire to run the system.  You must not have one but you might check your user manual to make sure that you don't have one and just have it turned off.  You would probably know.

First thing I would do is replace the breaker like you are suggesting.

@erik_squires will show up soon and he is expert in this subject so wait for his recommendation.

Jerry

Also, check with the manufacturer.  With AFCI breakers now required in all residential circuits this should be something they are aware of.

Ps, the online forums complaining about first gen. AFCI tripping have settled down quite a bit with the second generation CAFCI versions.

Last, really, ive seen power conditioners with very large toroids trip breakers, had nothing to do with AFCI

AFCI breakers react to arc signatures. The circuit should be gone through and all connections should be tightened. It’s possible that there is micro arcing somewhere. I have seen this resolve nuisance tripping before.

Many thanks for all the expert advice - much appreciated!

I think Accuphase amps have soft start - not sure about the power supply - but they all have large mechanical of/off switches that could be arcing.

I will ask the electrician to tighten the connections.

I’m not familiar with your amps or their power requirements, but this was my situation:

I have 5 year old Eaton 20 amp CH type AFI breakers and one started tripping after I got my new McIntosh MC611 amplifiers. The dealer took the amps back and thoroughly tested them and, of course, didn’t find any problems,  I called an electrician who replaced the breaker with a new one, and the problem went away.  He told me that those breakers had a recall on them so he’s coming back to replace them under warranty. 
 

I’m not competent to advise on Canadian electrical requirements, but there is something in how you describe the thing that leaves me puzzled.

I assume you have plugged the two amps into the PS-1250, but you are still switching them on manually and independently. You switch the PS-1250 on, then the monoblocks sequentially, and it’s on the second one that you get the AFCI tripping. If that’s not correct, ignore what follows.

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This, to my mind, rules out the PS-1250: if it was the inrush current into that, it would trip when you switch it on, not when you add a load to it.

I suspect that points to the second amp causing some micro-arcing that was previously snubbed by your passive conditioner (they work either way...), but not by the PS-1250.

Replacing the AFCI with a more advanced one may help avoid the tripping, but I would check the amp power switch’s health too... before it gets damaged (or damage progresses to a no-power-on situation). That is particularly the case if it’s always the same amp that causes the issue.

@Dievi67  good suggestion.  This can be tested by turning the amps on in the opposite order and seeing if it is still the second one that trips or if it is always the same amp that trips the breaker.

Jerry

Is a convenience outlet fed by a 15 amp breaker up to code in Canada? That aside, I would try another outlet on a different breaker to see if the probem follows there. Preferably an outlet on a 20 amp breaker with AFCI. Hope this helps. Also, it would be interesting to know what size wire is feeding that outlet. 

I almost firgot.  Afci, cafci and gfci breakers include diagnostic LEDs.  If they arent on you have a plain old overcurrent trip.

If it really is an AFCI tripping, consider swapping out power cords as well as changing the order of amplifier starts.

I do repeat though, first generation AFCI breakers (1999 ish) were more jittery than the second generation CAFCI breakers.