Two means of disconnects

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Davebones

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Location
North Of Tampa Fl
We have custom built hydraulic test stands with various motors from 3 hp to up to 150 hp . We have started running our control power ( 120 V ) through a GFI ( For Safety as oil and water sometimes leaks around stand )then it goes thru a lockable switch next to the controller cabinet . The 480V feed also has a lockable disconnect and is located by the controller cabinet . The controller cabinet is marked " Caution Two Sources of Power " . We started to do this as we see this as being safer since we can troubleshoot the control circuit without 480V present ( No need for arc Flash Gear ) . A supervisor has a problem because he thinks that one disconnect should isolate all the power on the stand . Just looking for some opinions on this set-up .
 
Good practices for industrial equipment are usually beyond the scope of the NEC. The NFPA79 is a good source for information. You can read it at the NFPA website
http://www.nfpa.org/aboutthecodes/list_of_codes_and_standards.asp?cookie_test=1

See section 5.3 to answer your question for good practice.

Nominally:
Each supply circuit must have a disconnecting means.
Where multiple supplies are present each disconnect must be posted with the location of all other disconnects for the machine.

Consider using Daykin LFTB-05 Z1183 is a 1kVA transformer with GFI breakers. or LFTB-07 Z1183 is a 500VA version.

Also note that you may be signing up for the ORANGE wire club. Sections 13.2.3.2 and 13.2.4.1
 
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