Question regarding Cat 4 safety circuit

I have three VFD motor drives. One is 480VAC from a set of fuses and a power distribution block, another is from a different fuse / distribution block supply, and the third gets its power from a 480 to 400 volt step-down transformer.

My questions is: in order to make it pass Cat 4 safety do I need two contactors in series to interrupt the power to the VFDs during an E-Stop press? That would make buying six contactors.

I have read some comments if it is better to interrupt the line or load side of the VFD but that is not my question. I am just wondering if I need two contactors per VFD.

Thank you

Yes, sounds like you will need two safety contactors in series per drive.

Depending on the supply wiring configuration it may be possible to have two safety contactors killing the supply to multiple drives while still meeting Cat 4 requirements but from your description doesn't sound like it's feasible.

In my experience it's better to kill the line/supply rather than the load.

I want to know who's Idea the 2 contactors is? owners of a contactor company? sorry