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Changing MCBs to RCBOs is it notifiable under part P

Now retired I am no longer a member of a competent persons scream, I was full scope member of NICEIC, 2391 qualified etc;   I can still hold a screw driver and press the buttons on my MFT when I can remember where I put them down.  

In the lovely house we built to retire in the 21 way consumer unit is full,  having had a lot of twinkly LEDs wiped out in the recent thunder storm , I think urge protection would be a good idea.

In order to free up the slots occupied by two RCDs and have space for the urge protector by simply changing the MCBs to RCBOs.  Is this notifiable under part P.

 I have done some other recent electrical changes and our local building control who are absolutely super relieved me of around £100 for the pleasure of fitting some 16A industrial sockets in my workshop because the work was indeed notifiable.    I would prefer not to have to pay another £100. 

  

Parents
  • i would say it is possibly notifiable. Not because you are changing the characteristics of the circuits, they were already RCD protected and they would be like for like replacements rating-wise, assuming you don't find nasties like discontinuous ring conductors. But because the SPD would need an OCPD to protect it. If using one of the RCBOs for overcurrent protection, to comply with 534.4.7 it must have immunity to surge currents of at least 3kA 8/20, so this should be checked with the RCBO manufacturer. So notifiable if a new SPD circuit is created.

    Edit; Also you would presumably be using mostly Type A RCBOs, instead if the existing Type AC (if they are?) pair, so technically the characteristics of the circuits would be changed.

Reply
  • i would say it is possibly notifiable. Not because you are changing the characteristics of the circuits, they were already RCD protected and they would be like for like replacements rating-wise, assuming you don't find nasties like discontinuous ring conductors. But because the SPD would need an OCPD to protect it. If using one of the RCBOs for overcurrent protection, to comply with 534.4.7 it must have immunity to surge currents of at least 3kA 8/20, so this should be checked with the RCBO manufacturer. So notifiable if a new SPD circuit is created.

    Edit; Also you would presumably be using mostly Type A RCBOs, instead if the existing Type AC (if they are?) pair, so technically the characteristics of the circuits would be changed.

Children
  • 17th ed was my last bible and my understanding of SPD and AFFD in domestic properties is far from complete some  CPD is missing.   The SPD devices sold in new consumer units do not have over current protection they sit next to the isolator.   So a bit confused when you say OCPD is needed ?

  • Some SPDs are required to be protected by an external OCPD; others have built-in protection - typically in the form of a one-shot soldered internal link.