If you limits switches are source devices, IOW they switch the +ve voltage, whatever you are using, 5v,12v 24v etc, and the grounded shield was cut through at the same time, this will likely blow the supply, or if no shield was used, in cutting the cable he made contact with ground.
If the switches are sourced from the PC, the PC P.S. common is at earth ground potential.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.