Grinder Tripping GFCI

S

SLC_Blades

Joined
Aug 20, 2018
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So I’ve spent the better part of three days moving all of my equipment over to my new house and I’ve recently run into some issues. My workshop at the new place is in the basement, and therefore has GFCI outlets. After running the extension cord and power strip, I found that my grinder immediately trips the GFCI, and my small Stinger vacuum does as well. I did several tests in order to isolate these devices and found that the power strip and extension cord are both fine and my issue isn’t related to amperage, as my setup is perfectly capable of running a 14 gallon shop vac and portable bandsaw at the same time. I did some research and found that steel dust could be the culprit, so I used my vacuum blower to thoroughly clean out the motor and VFD (even though they’re both totally enclosed and had virtually nothing in them) and still had the same problem. Both my grinder and vacuum work perfectly fine on regular outlets.
*the ground wires are also tight on everything*

Any ideas for what might be causing this?
 
Assuming you dont have current leaking to ground...
Some GFCIs are overly sensitive regardless.
Capacitive coupling between ground and the current carrying conductors can basically ’preload’ GFCIs leak current sensor. Any current surge then trips the GFCI. Applying reactive loads such as a motor aggravates the problem.
This problem often is greater with GFCI breakers due to the extra conductor length between GFCI whats in a loadcenter somewhere in the building and load.
A shorter distance as practical from GFCI to appliance will minimise that coupling effect.
 
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If your grinder has a VFD it will trip the GFI. I had to wire in a non-GFI receptacle beside a GIF to be able to run the VFD grinder in our garage.
 
VFD and GFI don't mix.
I put an intercom from the house to the shop a good while ago. Every time I used it it tripped the GFI on the house end. Turned out that the audio frequency wave the intercom puts on the AC line is more than enough variance to trip the GFI.
 
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