2. amps-preamps
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Nuisance tripping of AFCI circuit breaker by inrush of current when turning on amplifiers

I recently added an Accuphase power supply for my Accuphase mono blocks.  When I turn on the second mono block it trips the AFCI circuit breaker.  I had no trouble using the mono blocks with a Puritan Audio PSM 156 power conditioner, but it is passive.  The Accuphase PS-1250 is power regenerator with a huge toroidal transformer and a large mechanical on/off switch.  I imagine either the inrush of current from the PS-1250 + 2 mono blocks is too much for the AFCI breaker or their mechanical switches are creating arcs their algorithms do not recognize as normal.

I have a 10 year old Siemens 15 amp AFCI breaker, and my question is what best to replace it with?  I have read that AFCI breakers have improved considerably with less nuisance tripping, and the first step would be to use a current model as a replacement.  But is there a better solution?

Square D makes 'High Magnetic' AFCI breakers that are less prone to nuisance tripping, but I don't know if they would even fit in my panel.  I'm not sure if Siemens makes a similar product.

An electrician coming over at the end of the week, but I thought I would ask here as this must be an issue many audio hobbyists have encountered with AFCI breakers.

toronto416
toronto416 OP
245 posts
 

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.

randymaqp
11 posts
 

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. 
 

dlevi67
39 posts
 

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.

**************

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.

carlsbad2's avatar
carlsbad2
1,818 posts
 

@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

evelyn1
54 posts
 

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. 

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