A motor starter contains devices with very different jobs. The pushbutton requests a start, the contactor switches power, and the overload relay monitors overload conditions. NEMA industrial control standards provide a framework for assessing these products. NEMA is the US-based National Electrical Manufacturers Association.

Choose the publication by the question you need answered. IA 10039 deals with control-circuit and pilot devices such as pushbuttons. ICS 2 / IA 10036 concerns motor-control equipment. ICS 1 provides general requirements for industrial controls. The documents complement one another rather than making every device interchangeable.

A rating describes performance under stated conditions. Two products carrying the same current figure may serve different duties. Consider the motor, its starting load, the overload protection and the fuse arrangement together. Supply voltage, switching duty and operating conditions also belong in the selection.

The cabinet has its own requirements. Industrial control enclosure standards address enclosure construction, while NEMA enclosure types describe protection against specified environmental conditions. An IP code is not an exact substitute for a NEMA type. Openings and accessories can change the protection of the finished assembly.

For adjustable speed, look at drive requirements alongside the actual variable-frequency drive. A programmable controller (PLC) communication function is a different matter from switching motor power. Machine safety controls need their own design assessment. A NEMA conformity statement does not automatically establish UL certification or the safety of an entire machine.

Technical reference: NEMA / ANSI — Industrial Control and Systems