SP
Surge Protection Device
Limits transient overvoltages from lightning and switching.
Requirement
Section 443: protection against transient overvoltages shall be provided where consequences could result in serious injury, loss of life, interruption of public services, affect commercial/industrial activity, or affect large numbers of co-located individuals. For other cases, a risk assessment applies; SPDs are generally fitted in dwellings.
Key regulations
443.4534