The National Electrical Manufacturers Association (NEMA) has published ICS 20 “Informational Guide to Electrical Industrial Topics”.

This new publication provides information on various topics of interest
related to the application and proper usage of electrical equipment in
the global marketplace. Subjects include enclosure type ratings, wire
sizing, and feeder and branch circuits.

CLICK HERE to download ICS 20 for free.

CLICK HERE for NEMA.