Surge protection: what IS 10101 requires
A surge protection device (SPD) diverts transient overvoltages safely to earth, protecting equipment from spikes caused by lightning and network switching. Under IS 10101, surge protection must be assessed and is required in many installations - effectively standard on most new domestic and commercial work following a risk assessment, particularly where equipment loss would have safety, service or significant financial consequences. SPDs come in Type 1, Type 2 and Type 3, chosen for where they sit and the level of protection needed.
Transient overvoltages from lightning nearby, or from switching on the network can wipe out electronics in an instant. Surge protection devices guard against them, and IS 10101 has made them a mainstream part of Irish installations. Here is what the standard expects.
What an SPD does
Normally an SPD does nothing. When a transient overvoltage arrives a spike thousands of volts above normal, lasting microseconds it conducts the surge to earth and clamps the voltage to a safe level, then reverts. It protects everything downstream: boards, appliances and the increasingly expensive electronics in a modern home or office.
When IS 10101 requires one
IS 10101 requires the risk of transient overvoltage to be assessed and surge protection provided where the assessment calls for it. In practice that makes SPDs standard on most new installations, and particularly important where a loss would affect safety services, cause serious inconvenience or a significant financial or data loss. Where the assessment does not mandate one, an SPD is still commonly fitted for the protection it gives.
Types of SPD
| Type | Guards against | Typical location |
|---|---|---|
| Type 1 | Direct / partial lightning currents | Origin of installation, buildings with a lightning protection system |
| Type 2 | Switching and residual surges | At the consumer unit / distribution board (most common) |
| Type 3 | Fine protection for sensitive kit | Close to sensitive equipment, with Type 2 upstream |
For most homes and small commercial premises a Type 2 SPD at the board is the core device, with Type 1 added where there is a lightning protection system and Type 3 near especially sensitive equipment.
Fitting it
SPDs are installed in or beside the consumer unit and must be coordinated with the board and its protection, to IS 10101, by a registered electrician. WEW stocks SPDs and consumer units to suit - see our consumer unit selection guide.
Frequently asked questions
Is surge protection mandatory in Ireland?
IS 10101 requires the risk of transient overvoltage to be assessed and surge protection provided where the assessment calls for it. In practice that makes SPDs standard on most new installations, and they are widely fitted even where not strictly mandated.
What type of SPD do I need?
A Type 2 SPD at the consumer unit is the core device for most homes and small premises. Add a Type 1 where there is a lightning protection system, and a Type 3 near especially sensitive equipment.
Will an SPD protect against a direct lightning strike?
SPDs protect against transient overvoltages, including those induced by lightning nearby. Buildings at risk of a direct strike also need a lightning protection system, with a Type 1 SPD as part of a coordinated arrangement.
Source it at WEW
WEW (Waveform Electrical Wholesale) is your electrical wholesaler and lighting expert in Meath, supplying trade and homeowners across the region. Call in to the counter or the lighting showroom for stock, advice and everything referenced in this guide.