working clearance - 480 volt across from 120 volt

[winslowfam]

Hi...we are designing a replacement switchboard (480 volts) to be located in a room that has a PLC cabinet (120 volts) mounted on the wall across the room. NEC 110.26(A)(1) calls for 4 feet of clearance between the two panels. But, I believe there is an exception for a situation like mine that allows for smaller clearances if the work involves a retrofit...putting a new switchboard in the same place as the old one. Could someone point me to that exception in the code? I think it was added to the 2002 edition?

 

[qcroanoke]

Hi...we are designing a replacement switchboard (480 volts) to be located in a room that has a PLC cabinet (120 volts) mounted on the wall across the room. NEC 110.26(A)(1) calls for 4 feet of clearance between the two panels. But, I believe there is an exception for a situation like mine that allows for smaller clearances if the work involves a retrofit...putting a new switchboard in the same place as the old one. Could someone point me to that exception in the code? I think it was added to the 2002 edition?

110.26(A) (1) (c) maybe?

 

[winslowfam]

that's it. Thank you. The NEC handbook also describes this exception as a way of relief for upgrades.

 

[radiopet]

(c) Existing Buildings. In existing buildings where
electrical equipment is being replaced, Condition 2 working
clearance shall be permitted between dead-front switchboards,
panelboards, or motor control centers located
across the aisle from each other where conditions of maintenance
and supervision ensure that written procedures
have been adopted to prohibit equipment on both sides of
the aisle from being open at the same time and qualified
persons who are authorized will service the installation.

Are you going to be able to ensure the "underlined" portion of that allowance?