Surge protectors (SPD) for Malaysian homes: what they do, the ratings, and where they go in the DB

A surge protective device (SPD), or surge arrester, sits in the distribution board and diverts brief voltage spikes, such as those from nearby lightning arriving through the power cable, to earth. Malaysia gets a lot of lightning, so “should I add an SPD?” comes up constantly in electrical groups.

An SPD is a different device from the breakers next to it. An MCB protects cables against overload and short circuit, and an RCCB or RCBO protects people against earth leakage. An SPD does neither. A Type 2 board SPD doesn’t protect against a direct strike on the house, and surges can enter through other cables such as phone, TV and autogate wiring.

What the Energy Commission says

ST’s domestic wiring guideline makes an SPD depend on a lightning risk assessment under the Malaysian standard MS IEC 62305. A consulting engineer or an electrical contractor registered with the Energy Commission carries out that assessment, and it decides whether and what kind of protection is needed.

In ST’s example layouts:

• the SPD sits after the main switch and before the RCCBs;
• it’s fed through its own MCB or fuse.

Placement matters. An SPD wired after an RCCB sends surge current through it and can trip it in storms, which is one reason the example layout puts the SPD ahead of the RCCBs. Maxguard’s 2026 datasheets and Hager’s SPL pages give a maximum rating for that upstream fuse or MCB.

The earth it discharges into

An SPD diverts surges to earth, so electricians in Malaysian groups add a practical condition: get the earth tested first. Some aim for an earth reading under 10 ohms before fitting an SPD. That’s a practitioner rule of thumb, stricter than ST’s 200-ohm limit for a house protected by RCCBs, and not the same thing as ST’s 10-ohm figure where a lightning protection system is fitted. Others push back that getting that low can be expensive, and some called SPDs in new houses little more than decoration. How well an SPD works also depends on the right type and short connecting leads. Our earthing and surge guide covers the earth test and why houses trip in storms.

The ratings on an SPD

These terms appear on every brand’s datasheet:

• Type: a Type 2 SPD is the usual device for a house’s distribution board. Type 1 and Type 1+2 devices are rated for a lightning impulse current (Iimp) and belong where a building has a lightning protection system, or where the risk assessment calls for them, usually at a main switchboard. A smaller secondary arrester may be needed when protected loads are far from the incoming one: Schneider gives more than 10m for its Type 2 iPRD8. Type 3 devices are for use close to sensitive equipment. Schneider describes its Type 1+2 iPRD1 12.5r as protecting “against direct and indirect transient overvoltages”.
• Imax: the largest surge the device is rated to divert, in kA, often the number in the model name (iPRD40, SPL240R, MY2-40MAX: 40kA).
• In: the nominal discharge current, in kA. On the Maxguard and Hager Type 2 models it’s half of Imax or a little more.
• Up (voltage protection level): the voltage that gets through to your wiring during a surge. Lower is better. It’s quoted between specific conductors, so compare figures for the same pair (live–neutral, for example). A higher Imax doesn’t always come with a lower Up: Hager’s 65kA SPL265 has an Up of 1.9kV, against 1.3kV for its 20kA SPL220.
• Poles: a single-phase house uses 1P+N, a three-phase house 3P+N. Brands label these differently: Hager calls them “2P” and “4P”, and Maxguard’s newer codes end “/1+1” and “/3+1”.
• Earthing system: Malaysian homes use TT, where the house has its own earth rod; check the SPD is stated for TT. Models for IT earthing systems are not for homes.
• Replaceable cartridges and remote signalling: most modular SPDs let you swap a worn-out cartridge when its window turns red, and versions with a remote contact (Schneider “r”, Hager “R”, Maxguard “/A”) can report it to an alarm or indicator.

The SPD ranges we’ve researched

We’ve researched three brands’ SPDs on their Malaysian lists and websites:

• Schneider Acti9 iPRD: as of 6 October 2026, Schneider Malaysia lists 26 iPRD references: iPRD8, 20, 40 and 65 in 1P to 4P, with “r” versions for remote signalling. Schneider describes the iPRD20 as recommended for a “medium risk level” and the iPRD40 for a “high risk level”. Schneider Malaysia also lists the single-piece iPF K and the iPRF1 / PRD1 Type 1 and Type 1+2 arresters. Its Easy9 SPD range page has an empty Malaysian product list, even though a Shopee listing offers an Easy9 SPD code.
• Maxguard: as of 8 October 2026, Maxguard’s website has 27 SPD codes in two generations. The 2022 catalogue line (MY2-20MAX, MY2-40MAX, EL1C40, MY3-65MAX) is still listed, and most seller listings we found are for the MY2-40MAX. The M series (Type 2 M20 and M40, Type 1+2 M12.5M, and heavier models for main switchboards) has datasheets dated January 2026.
• Hager SPL: as of 8 October 2026, Hager Malaysia lists 17 SPD products: Type 2 at 20, 40 and 65kA, Type 1+2 at 12.5kA, and replacement cartridges. Its 40kA models come only with a remote contact (SPL240R, SPL440R). The plain SPL240 and SPL440 that sellers list are in Hager Malaysia’s 2022 brochure but have no Malaysian product page.

For a house DB, the Type 2 models line up like this:

Each brand also has 20kA three-phase models, and Schneider and Hager have 65kA Type 2 models (Maxguard’s 65kA MY3-65MAX is Type 1+2); the family pages list every code. Schneider and Hager both call their cartridges replaceable, and Maxguard’s 2022 catalogue says a “competent person” should check for operated modules and replace them.

Prices and listings to be careful with

Prices on 8 October 2026 for single-phase 40kA models, from Malaysian shops and marketplace stores:

• Maxguard MY2-40MAX 1P+N: RM131.85 at ene2u’s online shop and RM156.36 at CL Hardware in Kuala Lumpur; marketplace stores list it mostly at RM140–RM175.
• Hager SPL240: RM312.00 at Pentagon Electric Mart (Shopee and Lazada).
• Schneider iPRD40 1P+N (A9L40500): RM305.00 at that same Shopee store, RM400 on ene2u’s website on 6 October 2026, and RM735.00 on Schneider’s 2021 Malaysian list price before trade discounts.

In the one store we found that lists both, Hager’s and Schneider’s 40kA single-phase SPDs cost about the same. Maxguard’s costs roughly half. The pages linked above have the full price tables and three-phase prices.

Watch for listings that don’t match the maker’s codes:

• Some marketplace listings titled “Schneider surge protector Device IPR 40KA” were advertised without an A9L reference at RM138 (Shopee, 1P+N or 3P+N) and RM245 (Lazada, 3P+N), far below the RM586.44 an online shop asked for a genuine iPRD40 3P+N (A9L40600). “IPR” isn’t how Schneider Malaysia names these products, and we couldn’t verify them.
• “Maxguard MY1-C2/C4 Class C” SPDs aren’t on Maxguard’s website or in its 2022 catalogue.
• Hager “SPA201/SPA401 Monobloc” and “SPM240E” listings aren’t in Hager Malaysia’s product index.

For a device whose job is to fail safely during a surge, ask for the exact reference and check the ST-SIRIM label. If you’re replacing a DB, ask whether the quote includes an SPD; our DB upgrade guide has quotes with and without one.