Current going thru Ground

[mbrown1610]

We Had an Electrical contractor install service to 2 machines
He went thru main disc. and then into junction box with circuit breakers.
From in the junction box the lines are split to separate breakers.
The machines are both fed from same transformer. Problem arises
when one of the machines has a certain controller turn on we are reading
anywhere from 1-2 amps to ground? What would be the most common cause
of this?

 

[peteo]

It seems that the question is,
"Why would a machine's solid state controller cause 1-2 Amps on the ground wire to that machine."

I'm assuming that the machine is built using NFPA 79 standards, and that there is no actual ground fault. Are these purchased item or fabricated machines?

The first thing to do is question the reading itself. How was 1-2 amps arrived at... what kind of meter, etc.

Is the motor frame electrically connected to the chassis of the controller. The controller is electrically connected to the machine's 'grounding' bus bar... if the motor is too, there's one ground loop. A shield drain wire connected at both ends will almost certainly create a ground loop condition. In general, a solid state controller will emit pulses, which can radiate energy into conductors and conductive surfaces. Before digging into the machine itself, though, it's my experience that questioning the test is a 'real good' idea.