Molded-case circuit breakers for branch-circuit protection, switches and circuit-breaker enclosures - North American market (Ed. 14, 2025).
The standard covers molded-case circuit breakers, ground-fault circuit breakers, fuse-equipped circuit breakers, molded-case switches and circuit-breaker enclosures rated up to 1000 V AC and 1500 V DC and up to 6000 A.
These products provide service-entrance, feeder and branch-circuit protection in accordance with national installation codes (NEC/CE Code); the standard also covers instantaneous-trip circuit breakers used in combination motor controllers.
The standard excludes low-voltage power circuit breakers (UL 1066) and supplementary protectors (UL 1077). Earlier editions (for example, the 2013 tri-national edition) limited the scope to 600 V and 6000 A.
UL 489 certification (UL Listed) permits the product to provide stand-alone branch-circuit overcurrent protection in an installation under the NEC, including branch-circuit protection in a UL 508A industrial control panel. A UL 489 circuit breaker may replace a UL 1077 supplementary protector, but the reverse substitution is not permitted.
In the EU, UL 489 certification does not replace a declaration of conformity to IEC/EN 60947-2; for rolling stock intended for the US/Canadian market, a DC circuit breaker marked “UL 489 Listed” means a device tested as a full branch-circuit breaker at the stated DC voltage and interrupting rating.
The product undergoes a sequence of calibration (trip-characteristic), overload, endurance and short-circuit tests; the minimum short-circuit test current is 5000 A, and the overload test is performed at six times rated current (minimum 150 A).
After the short-circuit test, the circuit breaker must retain its ability to provide further overload protection. Insulation spacings between poles are 1 inch through air and 2 inches over surface. Products complying with UL 489 receive the UL Listed mark; circuit breakers with an interrupting rating other than 5000 A must be marked with their interrupting rating.
DC voltage ratings include, among others, 24, 48, 60, 65, 80, 125, 250, 500 and 600 V, and from 650 to 1500 V DC in 50 V increments.
Check whether the product is UL 489 Listed; UL 1077 Recognized status indicates supplementary protection only. Check the UL file number (E-xxxxxx), the certified range of rated currents and pole configurations, and the interrupting rating at the specific AC or DC voltage.
