Technical information

FEEDER AND BRANCH CIRCUITS

a) A pilot light shall comply with the Standard for Industrial Control Equipment,

UL 508, and a miscellaneous lamp holder shall comply with the Standard for

Edison-Base Lampholders, UL 496;

b) An electrically-operated valve shall comply with the Standard for Electrically

Operated Valves, UL 429;

c) A solenoid shall be evaluated for the intended use;

d) A time-indicating or time-recording device, including an hourmeter,or a

synchronous motor shall comply with the Standard for Time-Indicating and -

Recording Appliances, UL 863;

e) An electrically operated counter shall comply with the Standard for Time-

Indicating and -Recording Appliances, UL 863;

f) An audible signal appliance, including a horn, bell, or buzzer,shall comply with

the Standard for Audible Signal Appliances, UL 464; and

g) A coil or input circuit to another control circuit switching device or to a load

controller shall comply with other component requirements in this standard.

All others are considered loads and thus power circuits regardless of the voltage

and the load absorption.

In North America the distinction is generally made on the basis of the final load

function (motor,inverter,lights, resistors etc…) regardless of the power voltage

and the current e.g. a stepper motor powered at 24 Vdc with a load current of

200mA is considered power, a solenoid valve at 24 Vdc with a load current of 2

Ampere is command and control.

Note:lights and fans for electrical cabinets are considered command and

control circuits. If installed in the field (outside the electrical cabinet) they shall

however be considered power circuits.