" writes:


My friend had a 440 motor or line short right in front of him in an
elevator motor room. He was temporarily blinded for a couple days. He
said it felt like someone poured sand in his eyes.

OSHA has gotten religion on the arc flash issue. The #1 chance
for such that will kill folks is when you close a large
main/sub-main breaker. They can and do explode outward with
enough force to blow apart cabinets, taking out the chump
standing there closing the breaker.

There's now many types of motor/hydraulic powered breaker
closers. They attach with magnets, the arm is on the
handle. You stand 20 ft away behind Lexan etc and push
the button.

There's also required "arc-flash clothing" -- I think the point
being it won't catch fire and melt onto the skin, but I'm not
sure on this.

In residences, the NEC has spec'ed arc sensing breakers for
bedrooms/living rooms, I think. These can be a PITA as
brush-type motors [Skilsaw, etc] can trip them.


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