Overhead cranes Grandfather clause.

Status
Not open for further replies.

atbritts

Member
Article 610.61 (NEC) talks about the need for a fourth ground conductor for overhead cranes. this rule was introduced in NEC 2005 so my question is; do older than 2005 installations that do not have the 4th conductor have to be retrofitted?
I was told that OSHA is enforcing this rule now and I don't know if they are also doing it with older crane systems.
Thanks:confused:
 

hockeyoligist2

Senior Member
I don't know if they are enforcing it or not, but IMHO, I think they should. I had two OC's that were shocking the operators when they would touch the cable and/or hook. One guy almost fell because of the shock. I went over every inch of the cranes and couldn't find anything that could be causing the shock.

I installed a fourth rail (over the objections of our safety director, since it came from his budget) for a ground and it went away. It can be very dangerous, especially with older cranes. They get rusty and/or painted several times and lose their ground path.
 

stew

Senior Member
Sometimes the ground current can come from a partially gounded winding in a crane motor. not enough to trip anything but enuogh leakage current to shock someone. The 4th rail or conductor just conducts that current away I guess.
 

hockeyoligist2

Senior Member
My thoughts exactly Stew. It could have been static but they described the shock as more than static. Nothing has tripped since the ground was added. I also put my meter on the hook and cable to a known ground before I added the rail and it was open.
 
Status
Not open for further replies.
Top