Osha says - Electrician Talk - Professional Electrical Contractors Forum

Bkessler · 10-20-2009, 12:54 PM

I need to install an emergency shut off for a bank of outlets in a machine shop that has 4 different bench grinders plugged into them. There are three phases and a nuetral. I was thinking of a 120 volt start and a stop switch going to a 3 pole contactor. Does this sound right?

RIVETER · 10-20-2009, 02:22 PM

Did OSHA say this is required?

Chris Kennedy · 10-20-2009, 05:12 PM

Quote:

Originally Posted by Bkessler

I was thinking of a 120 volt start and a stop switch going to a 3 pole contactor. Does this sound right?

All on one circuit? HP ratings match up?

RIVETER · 10-20-2009, 07:47 PM

Why would OSHA be involved with this ; You can always run 120volt circuits through a contactor...but why would this be an OSHA mandate?

kbsparky · 10-20-2009, 09:28 PM

Are they looking for a panic-style stop switch? A red, mushroom shaped push-button type switch?

We recently wired a machine shop, and used those red stop switches connected to a shunt-trip main breaker in the equipment panel. Anyone can hit one of 3 stop switches to shut down the power for the whole shop.

Bkessler · 10-21-2009, 10:25 AM

I am not sure what osha has to do with it, It's just what the shop owner said, and I put in a regular push button stop and start with a 3 p0le contactor and he's happy now.

RIVETER · 10-21-2009, 02:07 PM

I've just never heard of an emergency shutoff for "cord and plug" equipment. It may be convenient, but you would still have to lockout to work on them, at least by our safety standard,

Sawdust454 · 10-21-2009, 02:37 PM

I bet it has to do with the grinders being able to automatically restart after a power failure. That is a requirement but I cannot cite the section right now.

RIVETER · 10-21-2009, 02:55 PM

I see your point...as long as the the start/stop switch contacts are momentary contacts. We have a lot that are mechanically ganged.

varmit · 10-24-2009, 04:55 PM

If these grinders are controlled by a maintained contact device, as a toggle switch, they would require two manual actions before they would restart. Pulling an E-stop button out to the "Run" position must not restart equipment. Usually a "Reset" button is paralled in the contactor holding coil circuit. The E-stop button is reset. Then the reset is pressed, and then you are back in bussiness.

Harry

brother · 10-24-2009, 08:38 PM

I would like to know what 'code section' that OSHA guy is citing. I too always thought if it was a 'cord and plug' in equipment then you would not need an e stop. ive been mistaken before.

mikeh32 · 10-25-2009, 02:36 AM

you might want to check into if these have to have lock out ability as well.

if its osha, i would imagine it would

rdr · 10-25-2009, 02:40 AM

Quote:

Originally Posted by RIVETER

I've just never heard of an emergency shutoff for "cord and plug" equipment. It may be convenient, but you would still have to lockout to work on them, at least by our safety standard,

Think it's more of a safety issue if say someone gets hung up in said "cord and plug" equipment.