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ABB S203-K50 — 3-Pole MCB (DIN Rail)

ABB S203-K50 50A 3-Pole K-Curve DIN Rail MCB, 480Y/277V

MPNS203-K50

ABB S200 series S203-K50, 3-pole K-curve miniature circuit breaker, 50 A, 480Y/277 V AC, 6 kA interrupting capacity, UL 1077 supplemental protector, DIN rail mount.

$22.23Ref. price · indicative, final on quote
ABB S203-K50 datasheet (PDF)
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

S203-K50 — Identification
ParameterValue
Number of poles3
S203-K50 — Electrical
ParameterValue
Voltage (AC)480
Current (A)50
S203-K50 — Protection
ParameterValue
Interrupting rating (AC)6 kA
S203-K50 — Mechanical
ParameterValue
Mounting typeDIN Rail
S203-K50 — Other specifications
ParameterValue
TypeTrip Curve K

Product details

S203-K50: 50 A K-Curve Supplemental Protector for 480Y/277 V Panels

It's built as a UL 1077 supplemental protector for 480Y/277 V AC circuits, with a 6 kA interrupting capacity.

The 480Y/277 V AC rating confirms it's rated for line-to-line 480 V and line-to-neutral 277 V wye systems — common in North American commercial and light industrial panels. The K-curve is the key selection parameter: it's the middle ground between C and D curves, with magnetic trip at 8–12× In, so it holds through motor start-up but still protects against hard shorts.

Deployment & Integration

The S200 series footprint is compact, so it fits tightly in multi-pole groups. Use it as a supplemental protector in branch circuits downstream of a main breaker or fused disconnect, typically in control panels, HVAC units, or machine-tool enclosures where UL 1077 listing is accepted.

Frequently asked questions

What is S203-K50's listed amps and trip curve?

The S203-K50 is rated 50 A continuous with a K trip curve. The K-curve provides magnetic trip at 8–12 times rated current, suitable for loads with moderate inrush.

Will S203-K50 drop into a panel specified around S203-D13 without rewiring?

Both are 3-pole S200 series breakers with the same DIN-rail footprint, so the S203-K50 will physically fit the same panel location as an S203-D13. However, the trip curve differs — K vs. D — so verify the load's inrush characteristic before swapping. The S203-D13 is rated 10 A, while the S203-K50 is 50 A, so a direct substitution without adjusting branch-circuit protection and conductor sizing is not valid.

What compliance documentation does the S203-K50 carry?

The S203-K50 is UL 1077 listed as a supplemental protector and CSA 22.2 certified. These cover North American installation requirements. For RoHS and REACH compliance, refer to ABB's documentation for the S200 series.

Where can I buy the S203-K50 and what's the lead time?

The S203-K50 is sourced to order through independent distribution. Availability and current pricing are confirmed at quote time against an RFQ. Submit a request for a firm quote with lead time.

MPN
S203-K50