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Compliance with 411.3.3 RCDs on Socket Outlets

I have a scenario where we have a standard circuit arrangement. 32A Ring Circuit feeding a number of socket outlets.  An RCBO of 32A/30mA is specified at the DB.  However the outlets also have 10mA RCD's at each outlet.    Whilst there may be issues around nuisance tripping. ITs been suggested that we remove the RCBO and use a standard 32A Type B MCB at the DB.

 IMO this means the circuit would not have RCD protection,  and only the outlets ( or appliance plugged into an outlet would be protected).  So the question I have is would a 32A MCB Ring circuit when serving this arrangement be compliant with the regs?

One concern I have with this is that should an outlet ever be changed for a normal 13A SSO, then the circuit again would be non compliant.   And that in the event of an earth fault (depending on the ZS) it may not achieve the necessary disconnection times for a ring circuit. 

 

Thoughts? 

Parents
  • Think it was because in 2015 BS7288 was updated. In it it said something like additional protection must be provided upstream of the device. Presumably additional protection was taken to mean an RCD by the JPEL committee, although it could possibly be argued it meant an OCPD. So we have the situation where a protective device needs another protective device, and it becomes unfit for purpose by default.

Reply
  • Think it was because in 2015 BS7288 was updated. In it it said something like additional protection must be provided upstream of the device. Presumably additional protection was taken to mean an RCD by the JPEL committee, although it could possibly be argued it meant an OCPD. So we have the situation where a protective device needs another protective device, and it becomes unfit for purpose by default.

Children
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