40A 2-Pole MCB 277/480V C-Curve UL489 - WEG UMBW-4C2-40 (55 characters)

The WEG UMBW-4C2-40 is a 2-pole thermal-magnetic miniature circuit breaker (MCB) rated 40A at 277/480VAC with a C trip curve, UL489 listed for branch circuit protection. This makes it suitable for use as branch circuit protection per NEC — a significant upgrade over UL1077 supplementary devices. Designed for DIN rail mounting with toggle actuation and visual status indication, it features a positive trip-free snap-action mechanism, a compact 17.5mm width per pole, and a cuttable bus bar connecting system for flexible panel layouts.
 
Key Specifications
Rated Current: 40A
Poles: 2
Trip Curve: C (5–10× In, general-purpose)
Maximum Voltage: 277/480VAC
Type: Thermal-Magnetic
UL Approval: UL489 (Branch Circuit Protection)
Standards: EN 60947-2, UL 489, UL 1077 (series)
Mounting: DIN Rail
Width: 17.5 mm per pole (35 mm total)
Visual Status Indication: Yes
Mechanism: Positive Trip-Free Snap Action
Series: WEG UMBW (1–63A, 1–3 poles, B/C/D curves)
 
Ideal for branch circuit protection in industrial control panels, machinery, lighting circuits, and DIN-rail-mounted distribution. UL489 listing makes it NEC-compliant for branch circuit applications where supplementary devices are not permitted. The C curve suits typical inductive loads such as transformers and motors.