The conductor connecting to motor controllers ant to control devices are required to be what material?

Question

to NEC...

Answer 1

Copper.

Answer 2

You can use any conductive material in wire or cable form. The considerations are more on the insulation side and the type of environment. Copper can be replaced by higher grade alloys that are resistant to corrosion.

Answer 3

The conductor is typically copper, but can also be aluminum. The NEC recognizes aluminum in its tables, but makes adjustments for the heating affect. You must allow for larger conductor size when using Al.

Also, the spacing of these conductors as well as the insulation will determine the size required for the Ampacity rating of the conductor.

The NEC also requires a Short Circuit rating to be considered when sizing conductors, this is a critical characteristic that should not be over looked. A good reference for MCC (motor control center) is referenced below.

It is important to know which NEC your area has adopted. Each state in the USA reviews and approves the NEC. Not all states adopt the same version 2002, 2005 or 2008 or possibly portions of given version.