A surge protective device (SPD), sometimes referred to as a surge suppressor, spike suppressor, surge arrester is a device that is intended to offer protection to appliances on the installation from transient voltage spikes.
These typically only last up to 30 microseconds, though they can reach over 1000 volts.
Lightning strikes can cause spikes greater than 100,000 volts which can cause cable to melt, and fires start from the vast heat generated.
Lightning strikes aside even modest voltage spikes can damage a range of electrical appliances.
These could be any permanently connected items such as washing machines, fridge freezers, televisions, computers, boilers, smoke alarms and so on.
As technology improves our home appliances have become more sophisticated – you may have for example seen the fridge freezers with screens on them so you’re not only able see the contents inside without opening the door, but you can also watch a movie on them as well as order grocery shopping or a takeaway.
This increased technology requires more electronics – more circuit boards with more sensitive components which are susceptible to failure from voltage spikes.
A surge protective device cannot guarantee to always protect sensitive equipment, but it can take surges up to a certain size before it is rendered useless and needs to be replaced.
How does it do this? By typically taking any voltage over a given size back down to earth and away from the downstream installation.
If you are having a EV car charger installed then it is worth noting these are full of electronic components – this is why it is best practice to install a surge protection device if you don’t already have one, even it is only to protect the EV charger itself.
Surge protection was introduced in the 18th edition wiring regulations which arrived in 2018. Initially as a recommendation, then a requirement with the amendment 2 which came into effect from October 2022.
It is possible to omit the installation of a SPD in a new installation or in a upgrade such as a consumer unit replacement but this requires a risk assessment which must be signed by the client.
Whilst it is possible, this isn’t something I am not offering – the cost and time to install a SPD is negligible and the benefits far outweigh any small cost saving.
** Combined Type 1 and Type 2 SPD’s are available and typically installed in domestic consumer units
If your SPD has failed (from a large surge) then it’ll usually display a red image instead of a green or clear image.
If this is the case then it’ll need replacement as it may no longer be offering any protection.
Contact a qualified electrician and arrange a replacement asap.
