What is an SPD?

A Surge Protection Device (SPD) is a device that is installed at the start of an electrical installation to protect electrical equipment from an electrical surge caused by a spike in the electrical supply from the Distribution Network Operator (UK Power Networks, SSE & National Grid) or a lightning strike. 

2 types of SPD can be installed:

Type 1

Type 2. 

Type 1 SPD

A Type 1 SPD is installed at the start of the electrical installation between the electrical meter and the consumer unit (fuse board). This option is used when a property has more than 1 consumer unit to protect. Type 1 SPDs are installed in their own metal enclosure and take up more space than a type 2 SPD. 

Type 2 SPD

A Type 2 SPD is installed inside the consumer unit (fuse board). This option is used when a property only has 1 consumer unit and is smaller than the Type 1 option as it fits inside the consumer unit and is the same size as a normal circuit breaker. 

When are SPDs used?

SPDs must be replaced and installed when rewiring your property or when installing a new consumer unit (fuse board). Either option is acceptable to be used.

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