6kA MCB – 20A 1 Pole C Curve (WMC120C)

The WMC120C is a 20 A single-pole 6 kA Miniature Circuit Breaker (MCB) designed for radial and equipment circuits subject to moderate inrush currents such as motors, compressors or EV chargers. Its C-curve tripping characteristic (5–10 × In) offers greater surge tolerance while providing rapid short-circuit and overload protection.

Fully compliant with BS EN 60898, the WMC120C fits Whitecliffe consumer units and any standard DIN-rail board. It provides a 6 kA breaking capacity and 20 000-operation mechanical life, making it ideal for domestic and light-commercial installations requiring inrush-resilient protection.

• 20 A rated current with C-curve (5–10 × In) tripping characteristic
• 6 kA breaking capacity at 230/400 V AC
• Single-pole design – 18 mm module width
• DIN-rail mounted – fits consumer units and distribution boards
• Complies with BS EN 60898 and BS 7671 (18th Edition A2)
• Service life: 20 000 mechanical / 8 000 electrical operations

The WMC120C provides 6 kA fault protection for radials and equipment loads with moderate inrush current. For standard domestic circuits, choose a B Curve MCB; for earth-fault and overload protection combined, see our Type A RCBO range.

• Part Code: WMC120C
• Type: Single Pole MCB
• Rated Current (In): 20 A
• Curve: C (5–10 × In tripping characteristic)
• Rated Voltage (Ue): 230/400 V AC
• Rated Frequency: 50/60 Hz
• Breaking Capacity (Icn): 6 kA
• Insulation Voltage (Ui): 500 V
• Impulse Withstand (Uimp): 4 kV
• Dielectric Test Voltage: 2 kV for 1 minute
• Thermal Reference Temp: 30 °C
• Operating Temperature: –5 °C to +40 °C (avg < 35 °C)
• Mechanical Life: 20 000 operations
• Electrical Life: 8 000 operations
• Mounting: 35 mm DIN rail (1 module width)
• Standards: BS EN 60898; BS 7671:2018 (Amendment 2)
• Typical Applications: Radials with motors, EV chargers or transformers requiring inrush tolerance

Install the WMC120C in a suitable consumer unit or distribution board by a qualified electrician. Match rating and curve to the circuit design and expected load profile.

• Mount securely on 35 mm DIN rail with correct busbar alignment
• Use C-curve for EV chargers, motors or transformer-based loads
• Confirm Z_s and voltage drop comply with BS 7671
• Tighten terminals to manufacturer torque values and record EIC results

When should I use a C Curve 20 A MCB?

Use on circuits feeding motors, pumps or EV chargers where start-up currents exceed the B-curve limit (5–10 × In tolerance).

Is the WMC120C compatible with Whitecliffe boards?

Yes – it fits all Whitecliffe consumer units and standard 18 mm DIN-rail enclosures.

Can this breaker protect an EV circuit?

Yes – the C-curve profile makes it suitable for most single-phase EV feed circuits. Always follow BS 7671 and manufacturer guidance.

What does 6 kA mean?

6 kA is the maximum fault current the MCB can interrupt safely. For higher fault-level sites, see our 10 kA range.

Do you stock D Curve versions?

Yes – Type D (10–20 × In) MCBs for industrial inrush loads are available on request. Contact our sales team for details.