Surge protection: what IS 10101 requires
A surge protection device (SPD) helps protect electrical equipment from transient overvoltages caused by events such as lightning and network switching. Under I.S. 10101, the risk from transient overvoltages must be assessed and surge protection provided where required. In practice, SPDs are commonly included in new domestic and commercial installations, particularly where equipment damage could have safety, service or significant financial consequences. SPDs are available as Type 1, Type 2 and Type 3, depending on their location and the level of protection required.
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 remains inactive. When a transient overvoltage occurs, potentially thousands of volts above normal and lasting only microseconds, the SPD conducts the surge to earth and limits the overvoltage. It then returns to its normal state, helping protect downstream wiring, appliances and sensitive electronic equipment from damaging voltage spikes.
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?
I.S. 10101 requires transient-overvoltage risk to be assessed and an SPD installed where the assessment requires it. SPDs are also commonly fitted in new installations to protect sensitive electrical and electronic equipment.
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.