Surge Backup Protector

The Surge Backup Protector is a dedicated backup protection device for low-voltage surge protective devices. It is designed for AC 50Hz or 60Hz power systems with rated voltage not exceeding 440V phase-to-phase. Installed in series with an SPD, it helps provide selective disconnection for power-frequency fault current and lightning surge current, reducing the risk of fire, short-circuit damage, and unsafe SPD failure in low-voltage distribution systems.

Unlike a standard circuit breaker used for general overload protection, this device is developed specifically for SPD coordination. When an SPD deteriorates, is punctured by abnormal transient overvoltage, or develops increased power-frequency leakage current, the backup protector can disconnect the fault path quickly. At the same time, when normal lightning current passes through the SPD, the device is designed to avoid nuisance tripping, keeping the lightning protection system available. This makes it a practical choice for distribution cabinets, building incoming panels, industrial control cabinets, communication rooms, photovoltaic combiner cabinets, and other systems where reliable surge protection and fire-risk reduction are required.

• Dedicated SPD backup protection for low-voltage AC power distribution systems.
• Selective disconnection of power-frequency fault current and lightning current.
• Helps prevent severe fire accidents caused by SPD short-circuit breakdown or aging failure.
• No nuisance tripping when lightning surge current passes through the SPD under normal protection conditions.
• Parameter-controlled tripping mechanism for accurate current discrimination.
• Low residual impulse voltage and high impulse withstand capability.
• High-energy contact structure for longer service life and stable operation.
• Compact modular body, convenient to install together with T1, T2, and T3 surge protective devices.
• Standard 35mm DIN rail installation in accordance with common panel mounting requirements.

• Ambient air temperature should not exceed +40°C, with the 24-hour average not exceeding +40°C; lower limit is -5°C for standard working conditions.
• Installation altitude should not exceed 2000m.
• The air should be clean. Relative humidity should not exceed 50% at +40°C; higher humidity is allowed at lower temperatures, such as 90% at +20°C.
• Install in a suitable distribution box or cabinet and avoid severe vibration, corrosive gas, water ingress, and mechanical impact.

• Backup protection for Type 1, Type 2, and Type 3 surge protective devices.
• Building main incoming distribution cabinets and branch distribution boards.
• Industrial control cabinets and equipment power protection systems.
• Communication rooms, server rooms, security systems, and weak-current cabinets.
• Photovoltaic, energy storage, outdoor distribution, and lightning-prone electrical installations.

The device should be installed by a qualified electrician and wired according to the correct system diagram. It is normally installed in series with the surge protective device so that it can disconnect abnormal power-frequency current while allowing lightning surge current to pass without unnecessary tripping. Before installation, confirm the SPD discharge current level, system voltage, pole configuration, and cable size. The device uses 35mm DIN rail mounting and should be fixed securely without looseness.

After installation, the device generally requires no further adjustment. During operation, check whether the backup protector has tripped. If tripping occurs, the protected SPD should be inspected immediately for aging, short-circuit breakdown, or failure. The test button should be pressed at least once every month to confirm that the protector operates correctly.

For reliable coordination, the Surge Backup Protector should be selected according to the SPD type, maximum discharge current, nominal discharge current, rated voltage, pole number, and installation system. For example, a specification such as SCB-40/4P-385 indicates a backup protection device selected for a corresponding SPD discharge level, pole arrangement, and voltage requirement. For T1 lightning current applications, models with Iimp coordination should be considered. For standard T2 distribution protection, SCB models should be matched to the SPD Imax and In values.

Regular inspection should include checking terminal tightness, operating condition, tripping status, and the condition of the connected surge protective device. If abnormal heating, visible damage, or repeated tripping occurs, disconnect power and replace the damaged component. When ordering, specify product model, pole number, rated voltage, quantity, and the SPD rating to be protected.

For project selection or bulk purchasing, please provide the SPD type, discharge current rating, pole configuration, voltage system, installation environment, and required quantity. Our team can help confirm a suitable Surge Backup Protector configuration and provide technical data, quotation support, and delivery information for your power distribution or lightning protection project.