About this service
A surge protective device, or SPD, limits short-duration overvoltages that could damage sensitive electronics, controls and appliances. Surges can arise from switching events on the supply or nearby electrical systems, and more severe events can be associated with lightning activity.
An SPD is normally installed at the origin of the installation or within suitable distribution equipment. It is not the same as an RCD, circuit-breaker or plug-in adaptor, and it does not provide direct lightning protection to a building.
Common problems we help with
Sensitive equipment has failed after a disturbance
Control boards, routers, televisions, alarms and smart equipment can be vulnerable to transient overvoltage.
New consumer unit without an SPD
The existing board may have been installed before surge protection became common or may lack space for an addition.
Solar, EV or smart-home equipment is being added
High-value electronic systems can make the consequences of surge damage more significant.
SPD status indicator shows failure
Many devices have an indicator showing when the protective module needs replacement.
How we carry out the work
Assess the installation
We consider supply arrangement, distribution equipment, connected systems and whether coordinated protection is needed.
Select and position the device
The SPD and protective arrangement are chosen for the installation, with conductors kept appropriately short.
Install, test and explain
Connections and protective measures are verified, and we show you how to check the device status indicator.
What is normally included?
- Initial discussion about the property, symptoms, priorities and timescale
- Assessment of the relevant circuit, equipment, access and existing protection
- A written scope for the proposed surge protection work
- The agreed installation or repair work, with disruption kept to a reasonable minimum
- Inspection, electrical testing and appropriate handover documentation
Before the work starts
- Condition of existing circuits before new protective equipment is fitted
- Available space, circuit identification and future capacity
- Earthing, bonding and supply characteristics
- How essential equipment will be managed during isolation and testing
What affects the price?
The price depends on the existing installation and the amount of work required. For surge protection, the main factors normally include:
- Circuit quantity and board configuration
- Defects revealed by pre-work or completion testing
- Meter tails, earthing and bonding alterations
- Labelling, containment and any necessary relocation
Testing, certificates and handover
Once the installation work is complete, we inspect and test it and provide the records that apply to the job.
- Updated circuit schedule and protective-device labels
- Test results and applicable installation certificate
- Guidance on testing residual-current devices
- Explanation of any separately identified future recommendations
Surge Protection questions
Does an SPD stop lightning hitting my house?
No. It limits transient overvoltage at the electrical installation. A structural lightning-protection system is a different specialist system.
Can surge protection be added to an existing board?
Sometimes, if compatible equipment and space are available. Otherwise a separate enclosure or board upgrade may be required.
Do plug-in surge strips do the same job?
They may provide local protection, but their effectiveness depends on the installation and they do not replace correctly coordinated protection at the origin.
Booking the work
What happens after you contact us
1. Discuss the job
Tell us about the property, the symptoms or the result you want. Photographs and model numbers are often helpful.
2. Inspect and quote
We check the relevant installation and give you a written quotation showing what is included.
3. Complete and test
We carry out the agreed work, verify it electrically and explain any controls, labels or certificates at handover.