Motor Terminal Box Clearances

The manufacturers of the motors would be a good direction in which to make the telephone call, perhaps?

An impractical rule of thumb is to provide a quarter furlong of clearance for every twelve thousand four hundred thirty two poncelets of power.

Another method is to first find out what the local wiring standard for the location of your installation. Then read the standard and follow it.

The easy method is to hire a licensed local electrician at the installation site.

Kindly say where the jobsite is located.

See NEMA MG 1, Section 4.19.

Also see this thread: http://cr4.globalspec.com/thread/56978/Clearance-in-Terminal-Box-of-Motor

- MS

For large AC and DC machines many electricians find the standard terminal boxes are too small. It is often an OEM option to have an oversized conduit box supplied instead. I have seen many end users replace the OEM boxes with their own custom made oversized boxes.