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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => AC Power and Grounding => Topic started by: Michael Storey on September 22, 2019, 05:43:32 am

Title: Another GFCI question
Post by: Michael Storey on September 22, 2019, 05:43:32 am
Had an event at the local fairgrounds today where the main power receptacle provided was a 14-50r, fed by a double-pole 50amp GFCI breaker. I have a cable that adapts this to a 50amp cali plug, which feeds the Amp Shop rack-pack in my main amp rack. The pack has edison's, and l6-20's which I use to power the I-Tech HDs at 220...

Every time I tried to power up, the 14-50r's GFCI breaker would trip. This was with the amplifiers off, but rear power switch on (unfortunately I didn't test with the rear power switch in the off position). Had to get things going so I plugged everything into one of my CS6365 bricks at 120v and had no issues the rest of the day.

I'm curious if this is normal behavior when powering devices at 208/240 across the two hots on double-pole GFCI breakers, or if there might be a wiring issue of some sort with my Amp Shop rack-pack? If the issue may be the rack-pack, is there anything in particular I should look for when I pop it open?
Title: Re: Another GFCI question
Post by: Stephen Swaffer on September 22, 2019, 09:56:15 pm
It should work fine running off of 208/240.  I would look  hard at the neutral/ground wiring.  Any connection after the breaker will cause a trip.  Hopefully the amps do not bottleg the ground for a switching circuit or such-I would assume they are built correctly, but the GFCI requirement ofr 50 amp 240 volt circuits is new as of 2017-it wouldn't surprise me to see some sloppy engineering exposed.