C Curve MCBs for Motor Loads & High-Inrush Circuits
C Curve MCBs are miniature circuit breakers designed for circuits with higher inrush currents, such as motors, compressors, pumps, power tools and certain commercial equipment. They provide combined overcurrent and short-circuit protection while allowing for controlled startup surges without unnecessary tripping.
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C curve devices trip between five and ten times their rated current, giving them greater tolerance for equipment that experiences load spikes during startup. They are available in a wide range of ratings and breaking capacities, making them suitable for workshops, plant rooms, garages, commercial boards and circuits with inductive loads.
- C curve tripping characteristics for moderate to high inrush circuits
- Ideal for motor-driven loads such as pumps and machinery
- Available in 6kA and 10kA versions for different fault levels
- DIN-rail compatible single-module designs
- Stable performance on circuits with fluctuating load profiles
C Curve MCBs are the preferred choice when equipment requires a stable supply during startup, without compromising safety or the ability to clear genuine faults quickly.
1 Pole 10kA MCB 32A C Curve WKC132C
£5.00
The WCED WKC Series 10kA Miniature Circuit Breakers (MCBs) are high-performance devices designed for precise overcurrent detection and short-circuit protection. Built to handle demanding applications, they provide reliable protection for domestic, commercial, and industrial distribution systems – including solar PV with SPD and EV charging...
1 Pole 10kA MCB 20A C Curve WKC120C
£5.00
The WCED WKC Series 10kA Miniature Circuit Breakers (MCBs) are high-performance devices designed for precise overcurrent detection and short-circuit protection. Built to handle demanding applications, they provide reliable protection for domestic, commercial, and industrial distribution systems – including solar PV with SPD and EV charging...
1 Pole 10kA MCB 10A C Curve WKC110C
£5.00
The WCED WKC Series 10kA Miniature Circuit Breakers (MCBs) are high-performance devices designed for precise overcurrent detection and short-circuit protection. Built to handle demanding applications, they provide reliable protection for domestic, commercial, and industrial distribution systems – including solar PV with SPD and EV charging...
What Is a C Curve MCB?
A C curve MCB is a miniature circuit breaker that trips when the current reaches between five and ten times its rated value. This allows it to handle higher initial demands without nuisance tripping, while still providing rapid protection under real fault conditions.
Where C Curve MCBs Are Used
- Workshops and garages with power tools or small machinery
- Heat pumps, HVAC systems and compressors
- Industrial and semi-commercial circuits with inductive loads
- Pumps, fans and motors with noticeable startup current
- Plant rooms and distribution boards feeding mixed mechanical loads
B Curve vs C Curve MCBs
B Curve: Trips at 3–5 × rated current. Suitable for lighting and general domestic circuits.
C Curve: Trips at 5–10 × rated current. Correct choice for circuits with motor loads or measurable inrush currents.
When to Specify a C Curve MCB
A C curve device should be used when the connected equipment causes a brief but legitimate surge on startup. Choosing the correct curve type prevents nuisance tripping and ensures stable operation during normal equipment cycles.
- Motor-driven equipment drawing a higher startup current
- Heat pump or HVAC systems with compressor loads
- Workshops and tools with intermittent bursts
- Three-phase equipment needing predictable overcurrent protection
Compliance & Standards
All C Curve MCBs in this category comply with BS EN 60898 and meet the requirements of the 18th Edition Wiring Regulations for overcurrent and short-circuit protection. They are suitable for new installations, upgrades and replacements.
Installer Benefits
C Curve MCBs provide dependable protection for circuits with mechanical or inductive loads. Their tolerance for higher inrush allows equipment to start correctly, while still delivering fast fault clearing and stable operation over time.