BG Electrical CUSPDT21EN Type 2 Single Phase Surge Protection Device

BG CUSPDT21EN — Type 2 Single Module Surge Protection Device, 40kA

The BG CUSPDT21EN is a Type 2 single-phase surge protection device rated at 40kA, engineered to divert transient overvoltages to earth in under 25ns. It mounts directly onto the consumer unit busbar with no backup MCB required, making it a fast, space-saving addition to any distribution board.

Suitable for TN, TNC-S and TT earthing systems, this single-module DIN rail device protects every load and circuit connected downstream, helping installers meet the latest 18th Edition Amendment 4 requirements with minimal panel space.

Safety & Reliability

The CUSPDT21EN features an inbuilt current-limiting circuit that melts safely under short-circuit conditions, releasing the internal connections into a failsafe open circuit. This triggers the device's status indicator automatically, so you know exactly when replacement is due — no guesswork, no unnoticed protection failures.

Tested to pollution degree 3 and rated for a -25°C to +40°C operating range, the device performs reliably even in demanding internal or external enclosure conditions where natural condensation can occur.

Installation & Compliance

Fixed to standard 35mm DIN rail with L/N/PE wire configuration, the CUSPDT21EN accepts cable up to 16mm² on the line terminal and 1.5–6mm² on neutral/earth, with clearly specified torque settings (3Nm line, 1.2Nm N/PE) for a quick, compliant first-fix. Pozidrive terminal screws speed up installation further.

Backed by a 100A gG maximum back-up fuse rating and full compliance with BS EN 61643-11, IEC EN 61643-11 and BS EN 62305, this device satisfies Regulation 534.4.5.1 of BS 7671:2018+A2:2022+A3:2024 (18th Edition Amendment 4) for SPD overcurrent protection.

Long-Term Assurance

Every BG Circuit Protection device carries a 10-year guarantee against faulty materials and workmanship, giving contractors and end users confidence in long-term performance without added cost.

Key Features of the BG CUSPDT21EN Include:

• Diverts Transient Overvoltages To Earth In Under 25ns For Fast, Effective Protection
• Mounts Directly Onto The Busbar With No Backup MCB Required, Saving Panel Space
• Suitable For TN, TNC-S And TT Earthing Systems
• Inbuilt Current-Limiting Circuit Creates A Safe Failsafe Open Circuit Under Short-Circuit Conditions
• Status Indicator Alerts Users When Replacement Is Required
• Tested To Pollution Degree 3 For Reliable Performance In Condensation-Prone Environments
• Type 2 Single Phase, 40kA Rated Device
• Operating Temperature Range: -25°C To +40°C
• Maximum Back-Up Fuse Rating: 100A gG
• BS7671 18th Edition Amendment 4 Compliant
• Compliant With BS EN 61643-11, IEC EN61643-11 And BS EN 62305
• CE And UKCA Marked
• Height: 84.5mm
• Width: 17.85mm
• Depth: 68.8mm
• Warranty: 10 Years

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