Why star ground????

**JAZZCNC** · 02-02-2016

Originally Posted by glynster

Are you suggesting that I should still bring over the earth wire from the VFD into my control box even though it's on a different plug? Should I do that instead of or as well as grounding it at its own plug? I thought I had to use a 15amp RCD breaker between the RFD and the power?

No if it's on it's own Plug then just use the Earth in Plug. Regards the Cable from VFD to Spindle only connect one end of shield and then just connect shield to Earth on VFD. No need take to Star point.

Originally Posted by glynster

Does that mean I should only connect the BOB ground temporarily while I do the setup? Otherwise the touchplate would be grounded (through my machine) to the star ground AND to the ground on my BOB. Hope that makes sense.

In theory the Bob Input Gnd will be tied to earth thru the PSU providing power so what you say is correct and will work but due to nature of BOB's being unreliable then it's best if you have Direct connection to the Gnd Input.