Richard Townsend, Technical Development Engineer at NAPIT, considers the changes in surge protection requirements with the introduction of BS 7671:2018+A2:2022.
Previously in BS 7671:2018+A1:2020
When surge protective devices (SPDs) took centre stage in BS 7671:2018, they became arguably one of the most significant changes in BS 7671 for some time.
Although surge protection had been around for many years, it was only given a cursory glance in previous BS 7671 editions. That risk assessment and greyscale map of the UK really did put the cat amongst the pigeons.
Even now, four years on, there remains confusion regarding what SPD type, where, and how to comply. There was constant feedback to the National Committee, JPEL 64, that it should simply be mandatory unless there is a particular client who doesn’t want it.
The National Committee listened to the feedback, deliberated the pros and cons, and have come up with the next step in surge protection for BS 7671. It wasn’t an easy process, and the DPC and subsequent alterations to the proposed changes were difficult to keep up with.
Regulation 443.4.1 was modified heavily; the complex risk assessment, the Calculated Risk Level (CRL) factor, and the greyscale map of the UK are no longer included, therefore removing all of the stuff that was difficult to understand.
It is now actually much simpler, with BS 7671:2018 +A2:2022 requiring that protection against transient overvoltages shall be provided where the consequence caused by overvoltage could:
(i) Result in serious injury to, or loss of, human life, or
(ii) Result in failure of a safety service, as defined in Part 2 or
(iii) Result in significant financial loss or data loss.
For all other cases, SPDs shall be fitted to protect against transient overvoltages unless the installation owner declines such protection and wishes to accept the risk of damage to both wiring and equipment as being tolerable.
There’s more, though; there’s always more!
As we can see, it has now become much easier to understand. There is, however, one more piece to the puzzle. The changes say that where the owner wishes to accept the risk of damage to both wiring and equipment as being tolerable, they can state they don’t want SPDs fitted. This is fine and is absolutely their prerogative.
This client refusal caveat is not new; it was in the original BS 7671:2018. However, the main difference is that this caveat is now available to all domestic, industrial and commercial installations. Therefore, if a business or homeowner doesn’t wish to have SPDs fitted, they don’t have to.
If a client states they don’t want SPDs fitted, our advice is to obtain this in writing as proof that they refuse to have them.
Any documented refusal to fit SPDs should be accompanied by a detailed explanation of the benefits of SPDs and the consequences of not fitting them. It is essential that the benefits are clearly explained to the client and documented.
A failure to obtain this documentation can result in a range of problems in the future, particularly if equipment is damaged, and the client claims they were unaware of the importance of the SPD.
That’s still not it!
Those of you with keen eyes will notice the particular wording of the second indent in the change to Regulation 443.4.1:
‘Result in failure of a safety service, as defined in Part 2’
As defined in Part 2 of BS 7671, the definition of a safety service roughly states that, a safety service is any system or equipment provided to warn people in the event of a hazard, or equipment essential to their evacuation. So that kind of changes things, as the caveat cannot be used to refuse the fitting of an SPD if any part of the installation is a designated safety service, which is fed from the supply that the installation of a SPD would protect.
Examples of safety services are:
- Fire alarm systems
- Emergency lighting
- Mains supplied smoke alarms fitted within dwellings
It is almost a given that every industrial, commercial and domestic dwelling should, or will, have some form of smoke detection, fire alarms or emergency lighting. The caveat to not install SPDs is almost meaningless now because there are very few installations, if any, that meet the criteria for not having SPDs installed.
Is it better?
We think the new approach represents a significant step-change in the fitment of SPDs. Gone are the long-winded risk assessments and the numerous ways of misinterpreting the Regulations, which could lead to failure to comply.
What is in now is simple to understand. SPDs are a part of our installation culture and they should almost always be installed.
It is much easier to operate this way as the confusion is gone. If you’re changing a CU/DB or making major modifications on a project, an SPD or SPDs should be fitted.
We still need to be careful though
In any case, great care should always be taken, as different earthing arrangements require different types of SPD, and if they are mixed up, the consequences can be disastrous. Likewise, SPDs used in PV systems, which are DC, must not be installed into AC systems, and vice versa.
Always seek manufacturers’ advice; if you are unsure of the type of SPD that should be used, they are more than willing to give you the advice you need.
To complement the launch of BS 7671:2018+A2:2022, all of NAPIT’s comprehensive suite of technical guidance publications have been updated to provide you with the latest advice. They’re available in print or electronic formats here
For more information on NAPIT scheme registration, click here