We have a Techserv Blue Marlin plasma table and I am getting a Hypertherm Powermax 105 to use with it. I have read numerous posts about fitting an earthing rod which seems a good idea to me.
I know that it is better to have the rod as close to the machine as possible but that would mean drilling through the factory floor which in itself is not a problem but as the place was built in the 1940's I would have thought that the ground under the floor is going to be very dry. I would like to put it just outside the building but that would be about 10/12 metres from the machine and I was wondering if this would have any detrimental effect. I have some 16mm diameter solid copper bar that I intend to use but what size/type of cable would be best to connect up with? Also, where is the best place on the table to connect this earthing wire to, my return cable from the Powermax is bolted directly onto the support bars at the end of the bed, should I connect the earth to the same place?