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How to Select a Replacement Circuit Breaker

4 min read

A circuit breaker protects a circuit from overload and short circuit. Replacing one is about matching the electrical ratings exactly — and, for panel fit, usually the same brand and series.

The ratings that must match

  • Current rating (amps): the trip rating — e.g. 16A, 32A, 100A.
  • Poles: 1-pole, 2-pole, 3-pole or 4-pole.
  • Voltage rating: matches your system (e.g. 240V, 480V AC; or a DC rating).
  • Interrupting capacity (kA / AIC): the fault current it can safely break — must meet or exceed the original.

Trip characteristic

  • For MCBs: trip curve B (resistive), C (general/mixed), or D (high inrush, motors).
  • For MCCBs: thermal-magnetic or electronic trip, often adjustable, defined by a frame size.

Type and panel fit

Identify whether it's a DIN-rail MCB, a molded-case breaker (MCCB), or a panelboard breaker. Within a panel, breakers must usually be the same brand/series to fit the busbar and interlocks. Common makes: Schneider, ABB, Siemens, Eaton, Allen-Bradley.

We'll match it safely

Send us the part number (or amps, poles, voltage and kA), and we'll quote the correct breaker. When in doubt, never down-rate the interrupting capacity — match or exceed it.

Need a part sourced?

Tell us the brand and part number — we source industrial parts from 4,000+ brands and reply with a written quote.

How to Select a Replacement Circuit Breaker | AllPartsIn