NEC code requirement for disconnect switch within sight of the motor 2

[ladengr]

Can you quote NEC articles, exceptions etc.for disconnect switch requirement within sight of the motor for a large facility with large motors? If trained maintenance persons are operating the facility 24/7, is it still necessary?

 

[rbulsara]

Remote (not within sight) disconnect has to be lockable in OFF position, then you can eliminate local disconnect. This is still within Code.

 

[dpc]

This is covered in NEC 430.102(B). Disconnect at motor is not required if conditions cited in this section are met.

 

[peebee]

What dpc said.

 

[busbar]

In commercial and institutional sites, sometimes the distinction between NEC Article 430 — Motors… and Article 440 — Air-Conditioning and Refrigerating Equipment is grey. {99} NEC 440-14 ‘location/disconnecting means’ seems a little more specific. The 440 verbiage may have evolved from national-consensus mechanical codes.

 

[ladengr]

Thanks for the info. Can you tell me whether an ammonia refrigiration plant for a food freezer storage is considered as an industrial process or an industrial occupancy. Here the facility is manned 24/7 and only qualified are permitted to work on the ammonia compressor motors.

 

[advidana]

what is the difference?

 

[timohearn]

Make sure to review NEC 430.113 and determine how it applies. For large facilities with large motors that may have multiple sources of power. For example, power to a space heater, lube oil heater, etc.. These sources may require individual disconnects within site of their respective load. I have been caught by this requirement before.