Hey David, hey @Doconefall,
to protect a human from the typical residual currents of a VFD (which are in the kHz range), you need special RCBOs. A normal domestic GFCI does not protect you and is of no use with a VFD.
Such a RCBO is very expensive, this one is about €500. I wanted to write an article to explain why you need them and how they work but did not find the time yet. It has to do with the carrier frequencies inside the VFD.
Meanwhile, be sure that you grounded and bonded your machine properly:
The use of a EMI filter matching the VFD is highly recommended. But be aware that to dimensionate an EMI filter, you need to know the input current of your VFD, otherwise the EMI filter can become a danger itself. On my VFD, the max input current is 24 A,
so the EMI filter is rather large.
Here you can see what accessories can help reduce the EMI and other side effects of a VFD:
– Source: Omron MX2 User’s Manual
Unfortunately, on cheap chinese VFDs, the input current is omitted on the nameplates and the manuals to hide the fact that with a 110 V VFD for single-phase input for a 2.2 kW spindle, you are at more than 50 A and there are no domestic circuits that can deliver that in the USA. So they omit the input current so the US customers nonetheless buy the cheap 2.2 kW spindle/VFD/water pump kits for 110 V.