16th Edition - Isolation

Here in the US, we have E-stop buttons that take a padlock. So the workman can use their lock on it.

daestrom

Sometimes a job like that might take six to eight hours, just 'lifting the leads'. Pretty extraordinary steps. Some folks I know take the stance of opening and removing the breaker from the cubicle. Problem with *that* approach is it doesn't stop someone from installing another breaker from another cubicle by mistake. They have to rely on the tagout hanging on the cubicle door (the locking mechanism comes out with the breaker).

daestrom

EN 60204 cover both Switch-disconnector, acc. to EN 60947-3 for appliance category AC-23 B or DC-23 B and Power CB suitable for isolation (acc. to EN 60947-2) for voltages upto 1000VAC, 1500VDC. The US equivalent is NFP 79, this has the same format, but is based on US practice. Normal UK practice is to isolate the machine from the supply and lock off the isolator. I never disconnect the cables from the machine.

BillB

NFPA 79 requires all machines to have an isolator that can be locked off.

BillB

I agree. That can be met with a circuit breaker that can be locked open, or can accept a locking device that in turn takes a padlock. I was commenting on the practice of *also* lifting leads. With large machines, lifting leads can be a difficult task. As I said, some folks take the approach of racking-out/removing the circuit breaker to 'lift the leads'. But doing so also removes the locking mechanism, so I think the protection that such actions affords is dubious.

Our lockout/tagout program allows the use of tags only to prevent operation that would damage equipment, but if personnel safety is involved, both locks and tags are required. We've been through this with a host of outside agencies, and all have agreed that our practices are acceptable for both NFPA and OSHA.

daestrom