Surge protection (SPD) — do you need one?
An SPD (surge protection device) guards your installation and the electronics plugged into it against sudden voltage spikes — from grid switching or nearby lightning. The current wiring regulations (18th Edition) expect an SPD in most installations unless a risk assessment justifies leaving it out, which is why modern consumer units include one. It's especially worth having if you have valuable electronics, solar, or an EV charger.
What a surge is
A transient overvoltage — a 'surge' — is a brief spike far above your normal mains voltage. Common causes are switching events on the grid, faults, and lightning striking near the network (a direct hit is rarer but more severe). The spike can damage or shorten the life of sensitive electronics.
What an SPD does
An SPD sits in the consumer unit and safely diverts that excess voltage to earth before it reaches your circuits, clamping the spike to a level your equipment can handle. It protects the fixed wiring and, to a degree, the appliances connected to it.
Do you need one?
Under the 18th Edition, an SPD is expected in most installations unless a documented risk assessment justifies omitting it — so a modern consumer unit will typically have one built in. If your board predates that and you have expensive electronics, a home office, solar or an EV setup, it's a sensible addition.
Isn’t a plug-in surge protector enough?
A plug-in strip only protects what's plugged into it, and to a limited degree. An SPD in the consumer unit protects the whole installation at the source, which is what the regulations expect.
Will an SPD stop all damage from lightning?
It greatly reduces the risk from typical surges and nearby strikes, but no device guarantees protection against a rare direct lightning hit. For normal surges it's very effective.
Can an SPD be added to my existing board?
Often yes, if there's space and the board is suitable — otherwise it's typically included as part of a consumer-unit upgrade. We can check after a look.