In the UK is your Domestic dwelling correctly protected by the SPD fitted in the CU/DB

BS7671 regulation 534.4.5, mandates that SPDs be protected against overcurrent via an MCB or Fuse
I think there are some other regulations which also state MCB/fuse protection is a requirement like


BS7671 reg 534.4.4.1.5
BS7671 reg 533.2.1
4BS7671 reg 34.5.1
BS7671 reg 712.534.101

This in my opinion goes against claims like the following and probably needs to be made clearer to the manufacturers, I would also suggest that BS7671 and GN (Guidance Notes) make this more clear for the Designer and Installer.
proteusswitchgear.com/.../

There are other manufactures also stating "No requirement for MCB" Proteus just happened to be the first my internet search engine came up with.


As always please be polite and respectful in this purely academic debate.

Come on everybody let’s help inspire the future.

Parents
  • I would like to know the real risk of not having an SPD. I was persuaded by this forum (and the 18th Ed) to fit one in my new installation and it did not break the bank, but we managed for almost three decades without one. So if the event is only very remotely likely, it really does not matter whether you have an OCPD or not.

    FWIW, mine has a C63 MCB and a red/green indicator lamp.

  • I don't know how you would qualtify the risk for any given house.  But the SPD is there to reduce the risk of a power surge (e.g. a lighning strike on a nearby power line) from frying your most expensive gadgets.

  • I don't know how you would qualtify the risk for any given house.

    We did in a rather approximate way in the 17th Ed.

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