Casing Live!?

Richard,

What should the resistance be between the casing and a copper water pipe or other pipe that goes to ground?

The other thing that came to my attention, is that there is no bonding to any of the copper pipes/sink unit.

RSD
December 2008

If your talking 240volt mains 'live' as opposed to some unusual static build up - you have one very dangerous machine there! You say you've done an earth continuity test -if the earth connection is good and complete to ground - then if the casing becomes live for even a fraction of a second it should be blowing a fuse and/or tripping out a circuit. If it isn't then either it isn't mains voltage or your earth circuit is not complete. Can I suggest you measure the resistance between the casing and a copper water pipe or other pipe that you KNOW goes to ground. (I have copper water pipes but they are fed by a plastic mains pipe!)
I am worried that your earth connection may NOT be going to ground and so giving you no protection at all. People get killed in these circumstances. Take great care!

Richard
December 2008