Specification

Overview of U.S. Standards and Regulations Motor Control Solutions

For more information on this transition, please refer to UL’s website for Industrial

Control Equipment Transition to IEC Standards.

Product Standards: UL 489 Circuit Breakers vs. UL 1077 Supplementary Protectors

UL 489 circuit breakers are used to protect feeder and branch circuits. UL 1077

supplementary protectors are intended for use as overcurrent protection within a

piece of equipment where branch circuit overcurrent protection is already provided.

UL 489 circuit breakers are required for compliance with NFPA 70 and NFPA 79.

UL 1077 supplementary protectors are redundant, or additional, protection on

branch circuits for equipment. They complement other branch circuit protection,

provided by either UL 489 circuit breakers or UL 248 fuses. UL 489 circuit breakers

can be used in place of UL 1077 supplementary protectors, but UL 1077

supplementary protectors can never be used in place of UL 489 circuit breakers.

Often times UL 1077 supplementary protectors are called circuit breakers, but this

is incorrect. Circuit breakers are listed to the UL 489 standard while supplementary

protectors are listed to the UL 1077 standard.

Certification Process

A nationally recognized testing laboratory (NRTL) can list or certify the equipment

according to applications or product standards including the following: UL, CSA,

ETL, TUV. Other approved agencies are listed at the following website:

http://www.osha.gov/dts/otpca/nrtl/index.html#nrtls.

Acceptance of Electrical Equipment in the U.S.

The process for acceptance is as follows:

1. The equipment is listed or the manufacturer is certified:

a. For mass production equipment, the industrial control panel itself is listed

by an NRTL.

b. For custom or low-volume equipment, the manufacturer or supplier of the

industrial control panel is certified.

2. A local inspector under the authority having jurisdiction (AHJ) inspects and

approves the electrical equipment and the installation prior to commissioning.

The product listing or labeling may be used to assist in the inspection.

Table 1 – Industrial Control Categories

Standard Product Description

Category Control

Number

UL 60947-4-1

Magnetic Motor Controllers NLDX

Manual Motor Controllers NLRV

Combination Motor Controllers NKJH

Auxiliary Devices (Overload Relays only, Thermal & Electronic) NKCR

Industrial Control Switches NRNT

UL 60947-5-1 Auxiliary Devices (Relays, Pilot Devices, Limit Switches) NKCR