Overview

The 6kA 40A RCBO (Residual Current Breaker with Overcurrent) represents the maximum single-phase current rating available in this RCBO series, delivering comprehensive high-power electrical safety by integrating both overcurrent protection and residual current detection into a single, space-saving 1-module unit. With a 40-ampere rated current, this RCBO is perfectly suited for the most demanding single-phase applications including large electric cookers and range cookers (up to 9.2kW), commercial catering equipment including heavy-duty fryers and ovens, industrial machinery, electric vehicle fast chargers (up to 9.2kW), large air conditioning units, whole-house electric heating systems, sub-main distribution circuits, and any maximum-capacity single-phase application requiring robust 40A protection before transitioning to three-phase systems. The device delivers 6kA rated short-circuit breaking capacity (Icn) with an exceptional 7.5kA service breaking capacity (Ics), ensuring reliable fault clearing under demanding conditions while maintaining full operational integrity for continued service after fault interruption.

Manufactured in strict compliance with IEC/EN61009-1 standards, this Type A RCBO provides 30mA residual current protection specifically engineered to detect both conventional sinusoidal AC leakage and the pulsating DC leakage currents generated by modern electronic equipment. The Type A characteristic offers superior protection compared to basic AC-type RCDs, making it essential for maximum-capacity circuits powering modern appliances with sophisticated electronic controls, switch-mode power supplies, inverters, and variable speed drives. With B-curve magnetic tripping characteristics (3-5x rated current = 120-200A trip range), this RCBO is perfectly calibrated for maximum-capacity power circuits where moderate inrush currents from motors, compressors, or heating elements must be accommodated without nuisance tripping. Operating on 230/240VAC single-phase systems at 50/60Hz, featuring pillar-type terminals accepting up to 25mm² cable, and rated for 30,000 mechanical operations, this 40A RCBO represents the ultimate protection solution for demanding residential high-power circuits, commercial catering installations, and light industrial applications requiring the maximum available integrated electrical safety in single-phase format.

Ultimate Protection for Maximum-Capacity Single-Phase Circuits

The 40A RCBO represents the highest current rating available for single-phase RCBO protection, addressing the most demanding applications before electrical systems must transition to three-phase supply. While a conventional MCB protects only against overcurrent and short circuits, and a standalone RCD provides only earth leakage detection often shared across multiple circuits, this integrated RCBO delivers both protection mechanisms simultaneously within a single 1-module DIN rail footprint. This integration is particularly valuable for maximum-capacity circuits where expensive equipment with sophisticated electronic controls (range cookers with digital displays and timers, commercial induction equipment, EV chargers with communication systems) requires both precise overcurrent protection and Type A earth leakage detection to prevent nuisance tripping while ensuring personnel safety. The 40-ampere rating makes this RCBO perfect for large electric range cookers and double ovens (up to 9.2kW total load), commercial catering equipment including heavy-duty fryers, chargrills, and combi-ovens, industrial machinery including large compressors, dust extractors, and workshop equipment, electric vehicle charging points (fast charging up to 9.2kW), large air conditioning units (up to approximately 9.2kW cooling capacity), whole-house electric heating systems or large electric boilers, sub-main distribution circuits feeding consumer units in outbuildings or workshops, and any maximum-capacity single-phase circuit where 40A protection is required with both fault current and earth leakage detection.

Furthermore, the Type A residual current characteristic elevates this RCBO above basic AC-type protection devices that are increasingly inadequate for modern maximum-capacity electrical installations. Standard AC-type RCDs detect only smooth sinusoidal AC leakage currents—adequate for pure resistive loads like simple heating elements but dangerously ineffective for contemporary high-power appliances containing sophisticated electronic controls and switch-mode power supplies. Modern equipment including range cookers with digital controls and timers, commercial induction cooking equipment with high-frequency inverters, EV chargers with communication and control systems, inverter-driven commercial kitchen equipment, and variable speed drives for industrial machinery all generate pulsating DC leakage currents that can desensitize AC-type RCDs, causing them to fail to trip when dangerous earth leakage occurs. The Type A rating detects both AC sinusoidal and pulsating DC residual currents, providing comprehensive protection for today's mixed-technology maximum-capacity electrical systems. With 30mA sensitivity—the internationally recognized standard for personnel protection against electric shock—this RCBO will trip within milliseconds (typically less than 40ms at 5x IΔn) when leakage current exceeds 30mA, long before ventricular fibrillation can occur. The mechanical endurance rating of 30,000 operations ensures long-term reliability, while the electrical endurance of 10,000 cycles provides confidence for permanent installations. For any 40A-rated maximum-capacity single-phase circuit where both overcurrent protection and advanced earth leakage detection are required, this Type A RCBO delivers uncompromising integrated safety in a compact, space-saving 1-module package.

Key Features

• Maximum 40A Rating – The highest single-phase current rating in this RCBO series for maximum-capacity applications

• Complete 2-in-1 Protection – Integrates MCB overcurrent protection and RCD earth leakage protection in a single 1-module unit

• Superior Breaking Capacity – Provides Icn=6kA and Ics=7.5kA (Ics higher than Icn for enhanced reliability)

• Type A Residual Current Detection – Detects both sinusoidal AC and pulsating DC leakage currents for modern electronic loads

• 30mA Personnel Protection – Standard sensitivity for electric shock protection with millisecond trip response

• B-Curve Magnetic Trip – 3-5x rated current (120-200A) tripping characteristic ideal for maximum-capacity appliance circuits

• Single-Pole Compact Design – 1P configuration with 1 module width for space-saving DIN rail installation

• Exceptional Cycle Life – Rated for 30,000 mechanical operations and 10,000 electrical operations

• Generous Cable Capacity – Pillar terminals accept up to 25mm² conductors for flexible installation

• IP20 Protection Rating – Suitable for installation within consumer units, distribution boards, and enclosures

• Wide Operating Temperature – Functions reliably from -5°C to +55°C, stores from -25°C to +70°C

• High Dielectric Strength – 2500V insulation withstand for enhanced electrical safety

• Top Supply Orientation – Designated power supply direction for correct and safe operation

Technical Specifications

• Product Type: RCBO (Residual Current Breaker with Overcurrent) – Maximum Single-Phase Rating

• Rated Current: 40 Amperes

• Number of Poles: 1P (1 module width)

• Rated Voltage: 230/240VAC

• Short-Circuit Breaking Capacity (Icn): 6kA

• Service Breaking Capacity (Ics): 7.5kA

• Magnetic Tripping Characteristics: B Curve (3-5x In = 120-200A trip range)

• Residual Tripping Characteristics: Type A (AC sinusoidal + pulsating DC detection)

• Rated Residual Current: 30mA

• Mechanical Endurance: 30,000 operations

• Electrical Endurance: 10,000 operations

• Frequency: 50/60 Hz

• Dielectric Strength: 2500V

• Power Supply Orientation: Top supply only (UP)

• Terminal Type: Pillar type

• Maximum Cable Termination: 25mm²

• Screw Torque: 2.5 Nm

• Protection Grade: IP20

• Operating Temperature: -5°C to +55°C

• Storage Temperature: -25°C to +70°C

• Standards Compliance: IEC/EN61009-1

Frequently Asked Questions

1. What applications require a 40A RCBO rather than a 32A?
A 40A RCBO is required when the connected load exceeds 32A (approximately 7.36kW). Typical applications include large electric range cookers (9.2kW maximum, drawing exactly 40A at 230V), commercial catering equipment including heavy-duty fryers and ovens (typically 8kW-9.2kW), electric vehicle charging points (9.2kW fast charging), large air conditioning units (8kW-9.2kW cooling capacity), whole-house electric heating systems, and sub-main circuits feeding workshops or outbuildings. If your appliance rating exceeds 9.2kW (over 40A), you must upgrade to a three-phase supply or use a higher-rated MCCB.

2. Why is this 40A RCBO the maximum single-phase rating available?
In single-phase electrical systems, 40A represents the practical maximum continuous current before significant engineering challenges arise. At 40A and above, voltage drop becomes critical over relatively short cable runs (requiring 10mm² or 16mm² cable), and many domestic and commercial single-phase supplies are limited to 60A-80A total. For loads above 40A, electrical regulations typically require three-phase supply (400V) to balance the load and reduce conductor sizes. This 40A RCBO is the highest rating in the RCBO series, with 63A MCBs available separately for the rare applications requiring single-phase protection above 40A.

3. Can I use this 40A RCBO on a circuit with a 40A continuous load like a 9.2kW range cooker?
Yes, with careful consideration. For a 9.2kW range cooker at 230V (exactly 40A), this is technically a continuous load if the oven operates for 3+ hours. However, range cookers typically cycle on and off as thermostats operate, so they are not considered continuous loads under most regulations. Nevertheless, the wiring regulations recommend diversity calculations for cooking appliances. For a 9.2kW cooker, the actual demand after applying diversity is approximately 15-20A, so a 40A RCBO provides adequate protection. Always use minimum 10mm² cable (16mm² recommended for runs over 20 metres) and consult BS 7671 for specific diversity calculations.

4. What is the significance of Ics=7.5kA being higher than Icn=6kA on this maximum rating RCBO?
Icn (6kA) is the rated short-circuit breaking capacity—the maximum fault current this RCBO can interrupt once and remain safe for continued use. Ics (7.5kA) is the service short-circuit breaking capacity—the fault current the RCBO can interrupt and still remain fully functional for normal service. Having Ics higher than Icn is a premium reliability feature, especially important at the maximum 40A rating. It means if this RCBO clears a fault up to 7.5kA (25% higher than its rated capacity), it will continue operating correctly without needing replacement. Most standard protective devices require replacement after clearing any fault at their Icn rating. This provides superior reliability and lower maintenance costs for expensive high-power equipment.

5. What cable size is required for a 40A circuit protected by this RCBO?
For a 40A circuit, the minimum recommended cable size is 10mm² for standard PVC-insulated copper conductors in open air or clipped direct. For longer runs exceeding approximately 25 metres, or for cables installed in thermal insulation, conduit with other circuits, or in high ambient temperatures, 16mm² is strongly recommended to prevent excessive voltage drop (maximum 5% for power circuits = 11.5V at 230V) and ensure adequate fault current carrying capacity. The terminals on this RCBO accept up to 25mm², allowing for substantial oversizing where voltage drop is a concern. For range cooker circuits, 10mm² is generally sufficient for runs under 20 metres, with 16mm² recommended for longer installations. Always consult BS 7671 (IET Wiring Regulations) for specific installation methods and derating factors, as 40A circuits have more stringent requirements than lower-rated circuits.