2 Pole A-Type 100mA Time Delay RCD
The WCED WARTD Series A-Type 100mA Time Delay RCD is designed for upstream fault protection in dual-RCD or discrimination setups. Often called an S-Type RCD, its built-in delay ensures downstream devices trip first, preventing unnecessary power loss across unaffected circuits. Suitable for both single-phase and three-phase TN or TT systems,...
The WCED WARTD Series A-Type 100mA Time Delay RCD is designed for upstream fault protection in dual-RCD or discrimination setups. Often called an S-Type RCD, its built-in delay ensures downstream devices trip first, preventing unnecessary power loss across unaffected circuits.
Suitable for both single-phase and three-phase TN or TT systems, this device is trusted in EV charging infrastructure, heat pump and solar PV installs, and industrial distribution boards where selective coordination is critical. Fully compliant with BS EN 61008-1 and the 18th Edition Wiring Regulations.
- Time delay function – ensures upstream discrimination in series RCD setups
- Available sensitivities: 30mA, 100mA, or 300mA
- Rated currents: 63A, 80A, or 100A
- A-Type residual current detection – covers AC + pulsating DC leakage
- DIN-rail mountable – compact 36mm design
- Compatible with RCBOs and SPDs for full system protection
Built for coordination between multiple protection devices, this RCD helps maintain supply integrity while still providing safe disconnection. Always install in line with BS 7671 and your consumer unit design requirements.
What is a 100mA time delay RCD used for?
It’s designed for upstream protection in circuits with multiple RCDs. The delay ensures that only the RCD closest to the fault trips, maintaining supply elsewhere. Commonly used in distribution boards and EV charger installs.
Can I use this in EV or solar systems?
Yes – it’s often installed as the upstream device in EV charging setups, renewable installs, or generator-backed systems to achieve RCD discrimination.
Is this compliant with 18th Edition regs?
Yes. It complies with BS EN 61008-1 and supports coordination requirements under the 18th Edition Amendment 2.
Do I still need surge protection with this unit?
Yes – a time delay RCD does not provide surge suppression. For full compliance and protection, install alongside a Type 2 SPD where required.
- Type: A-Type (S-Type) Time Delay RCD
- Sensitivity: 30 / 100 / 300mA (set internally)
- Poles: 2P
- Current Ratings: 63A, 80A, 100A (selectable)
- Dimensions: 36 x 82 x 70mm
- Rated Operational Voltage: 230/400V, 50Hz
- Short Circuit Rating: 6kA
- Mechanical Endurance: 4000 cycles
- Electrical Endurance: 2000 cycles
- Ingress Protection: IP20 (BS EN 60529)
- Compliance: BS EN 61008-1
- Recommended Torque: 2.5Nm
Time delay RCDs should only be used where discrimination is needed — typically as the upstream device in multi-board or split-load setups. Always confirm placement during design or testing stages.
- Mount directly to DIN rail inside suitable enclosure
- Ensure correct torque is applied to terminals (2.5Nm)
- Time delay should not be used on final circuits without discrimination needs
- Install by a qualified electrician only
