2. amps-preamps
  3. 193049-343

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

Showing 1 response by dlevi67

dlevi67
55 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.

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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.

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