Machine service disconnect problems/questions

[JohnGurdak]

I work in a plating house and the enviornment is very corrosive. They have burned out numerous machine disconnects due to corrosion. Is it legal to place a magnetic contactor elswhere and control the coil with a lockable remote switch mounted near the equipment?

Thanks

 

[raider1]

Yes, but you will still need a disconnecting means for the motor controller within sight of the controller as well as a disconnect within sight of the motor unless you meet one of the exceptions to 430.102(B).

Chris

 

[JohnGurdak]

Thanks for the reply. It's not a motor it's a transformer for heating coils on a hot solution bath. Not sure if that would make a difference.

Wanted to mount the magnetic contactor on the wall outside the room to avoid the corrosive fumes and put a small lockable corrosion resistant lockout switch by the unit.

 

[pfalcon]

Thanks for the reply. It's not a motor it's a transformer for heating coils on a hot solution bath. Not sure if that would make a difference.

Wanted to mount the magnetic contactor on the wall outside the room to avoid the corrosive fumes and put a small lockable corrosion resistant lockout switch by the unit.

Locks/tags shall only be installed on circuit disconnecting means. Control devices, such as push-buttons or selector switches, shall not be used as the primary isolating device.

Magnetic contactor? Lockout switch? Disconnecting means will physically separate all ungrounded conductors. This cannot be done electrically.

If you can't find a 4X disconnect then mount one inside a 4X enclosure.

 

[JohnGurdak]

Perhaps I worded it incorrectly
It's controlling a transformer for a hot water bath and not a motor. I know NEC 430.102 requires a disconnect for all motors but could find no requirement for transformers. This is a convieience (? for lack of a better term) disconnect. I found no NEC requirement for transformers. NEC 230.70 now allows for service entrance disconnects to use shunt trip with remote control. Although not a magnetic contactor it is an electrically actuated disconnect.

 

[pfalcon]

Perhaps I worded it incorrectly
It's controlling a transformer for a hot water bath and not a motor. I know NEC 430.102 requires a disconnect for all motors but could find no requirement for transformers. This is a convieience (? for lack of a better term) disconnect. I found no NEC requirement for transformers. NEC 230.70 now allows for service entrance disconnects to use shunt trip with remote control. Although not a magnetic contactor it is an electrically actuated disconnect.

70E requires the LOTO point must physically hold the conductors open. You can use a remote shunt breaker but you can't lock out at the remote. You still have to go to the disconnect itself. I also suggest you perform the labeling normally used on motors with remote disconnects.

 

[JohnGurdak]

Think I found my own answer

Think I found my own answer

Reading another thread I think It's acceptable to put a standard disconnect in another location away from the corrosive fumes as long as it's properly marked. Am I interperting this correctly?

450.14 Disconnecting Means. Transformers, other than
Class 2 or Class 3 transformers, shall have a disconnecting
means located either in sight of the transformer or in
a remote location. Where located in a remote location,
the disconnecting means shall be lockable, and the location
shall be field marked on the transformer.

 

[pfalcon]

Reading another thread I think It's acceptable to put a standard disconnect in another location away from the corrosive fumes as long as it's properly marked. Am I interperting this correctly?

450.14 Disconnecting Means. Transformers, other than
Class 2 or Class 3 transformers, shall have a disconnecting
means located either in sight of the transformer or in
a remote location. Where located in a remote location,
the disconnecting means shall be lockable, and the location
shall be field marked on the transformer.

New code for 2011 NEC. Conforms to my prior posts which are 2008 NEC and 2009 70E. The disconnect remains your lockout point even though it's in a different room. You cannot use the switch you suggested as a lockout point. I suggest that if you use a switch in the room that it not be provided with lockout points. Further that the marking required in 450.14 be posted at the switch as well (though maybe in brief form).

 

[renosteinke]

Not to quibble ... but any atmosphere that eats up your disconnects can't be doing the transformer any good!

The food service industry uses plenty of stainless steel disconnects. Between the wet environment, the salt in the product, the degreasing lye soap, and the chlorine bleach sanitizer, food plants are pretty corrosive. If your situation is more severe, I'd look to relocating the equipment.

Ever notice how a firm will spend $$$$ to protect equipment, but not a nickel to ease the worker?