Surge protection and the 18th edition regulations…

Today I would like to talk to you about Surge Protection and the 18th edition regulations…









There has been a lot of noise in 2019 about the correct use of surge protection devices while conforming to the 18th edition so today I am going to go through the regulations and use my specialist knowledge in surge protection to explain when, where and how SPD’s should be installed.

In the regulations there are a few installations where surge protection must be fitted:

(Page 101, Regulation 443.4)

Where the consequences of over voltage could:

– Cause serious injury or loss of human life.

Here everyone always considers hospitals and doctors surgeries, where in fact this single line covers a lot of the installations that most contractors work on daily. Under this regulation, any board feeding emergency lightning or fire alarm panels must have surge protection installed. This is because if this equipment was to be damaged, it could mean a potential injury to people within the building.

– Damage of public services or cultural heritage.

For public services this could be anything from a train station to a library, or even motorway services. If it can affect a public service an SPD must be installed. For cultural heritage, this is to mainly protect important historical remains from potential damage, especially when dehumidifiers, or other critical equipment are used to prolong the lifespan of historical objects.

– Interruption to commercial and industrial activity.

This one we have just covered in our last article, but is pretty self explanatory.

– Could affect a large number of co-located individuals.

This could be anything from a school to an exhibition centre or even a block of flats. If electrical damage can affect a large group of people, then an SPD must be installed.

When applying these regulations, it is important to understand that the regulations are not retrospective, therefore will only apply if you are installing a new distribution board or making a significant amendment to an existing installation.

For all other installations, either an SPD is installed or there is a risk assessment which can be performed which will give you a risk level, to state if SPD’s are needed in that installation. I will go further in to the risk assessment method in our next article.

The exception is single dwellings, where an SPD can be omitted if the value of the installation is not seen as significant. This is not a very clear regulation. Essentially it means that the contractor must discuss with the installation owner whether they want an SPD installed or not. It is recommended that if you discuss SPD’s with the home owner and they decline to have them installed, that you get a paper confirmation of this, whether that is on the quote itself or in a declaration such as the document available through NAPIT. This will ensure that if any damage is caused in the future, which could have been averted through the use of an SPD, that the contractor will have proof that it was declined by the customer.

That is most of the regulations surrounding the use of SPD’s. The last thing I would like to mention is the mixing manufacturers regulation. Essentially, as an SPD is installed from an MCB and not directly on the busbar system, it does not affect the integrity of the consumer unit. Also as an SPD is a voltage detection device, it does not have a short circuit withstand capacity, such as an MCB, so does not require type testing to any specific manufacturer. With SPD installation, it is very important to keep the cable lengths as short as possible, so by installing the SPD in the consumer unit, you are keeping these cable lengths to a minimum. Therefore, any manufacturer who states that a contractor must use their SPD is using this regulation for commercial benefit, not to enhance the safety and integrity of our electrical systems, which is what BS7671 was designed to do.

Thanks for reading, if you have any more questions please get in touch with our technical support team on 01484 851 747.

Kirsty Johnson, Technical Sales Director