Installation Guide

SCCR Requirement in UL 508 A Motor Control Solutions

Method 3 is often called tested combination rating. Individual motor branch circuit

components are tested together in specific combinations to achieve a system rating.

This system rating is not specifically limited by each individual component rating.

It is important to note that use of one method only is not required. It is very common

to find systems that utilize two, if not all three, methods for determining SCCRs.

Component SCCR ratings offer the user of power control products a great deal of

flexibility in the application of these products. A component SCCR rating for a

contactor and overload relay typically calls for a maximum circuit breaker size

which is not tied to a specific part number or combination of multiple specific part

numbers. A similar scenario exists when using fuses for short circuit protection of a

power control product. A fuse class and maximum size are what’s called for, not a

specific fuse or fuse holder; part numbers are not necessary. The component

ratings for Schneider Electric contactors, overload relays, and motor starters are

printed on the product labels and/or the product instruction sheets.

UL 508A Support Websites

Schneider Electric offers UL 508A support on our website at www.Schneider-

Electric.us. A number of educational and product search tools are available,

including overview information, a UL 508A SCCR determination flow chart, and

information on our individual and combination product SCCRs. UL also publishes

SCCR tested combination ratings on its website (refer to link below).

Schneider Electric’s updated tested combination ratings can be found on both

websites and is free to download.

Schneider Electric’s UL 508A Support Website:

http://www.schneider-electric.us/sites/us/en/support/product-support-resources/ul-

508a-support/ul-approved-tested-combination-spreadsheets-with-sccr-data.page

UL’s Short Circuit Current Ratings for Combination Motor Controller

Components Website: http://industries.ul.com/industrial-systems-and-

components/industrial-control-products-and-systems/short-circuit-current-ratings-

for-combination-motor-controller-components