IET announces new amendment to BS 7671 (IET Wiring Regulations)

" SRCDS are only intended to supplementary protection downstream of the SRCD. SRCDs are intended for use in circuits where the fault protection and additional protection are already assured upstream upstream of the SRCD".


So these devices can no longer be used for additional protection.

Surely such an interpretation defies common sense? Why on earth would a standard for 30mA RCD sockets intend to demand upstream 30mA RCD protection - it just isn't logical. Isn't it far more likely that the intention was simply to re-enforce the point that the device doesn't provide upstream protection (as would be commonly be needed these days - e.g. for T&E concealed in a wall) and that something got lost in translation from during the committeeitization of the prose?

 

So BS7671, crucially in the "selection and erection" section, removed BS7288 as "accepted devices"

I don't think that BS 7288 has been "removed" as such - before the 18th there wasn't a list of acceptable devices (some devices were mentioned elsewhere and had useful data provided for them, but as far as I can tell there was no implication that other devices couldn't be equally acceptable) - just some very specific performance requirements (e.g. rated ≤30mA and opening within 40ms at 5xI_Δn). Come the 18th the performance requirements disappeared (perhaps because some devices now need 250mA rather than 150mA to open within 40ms) and we just had a list of acceptable devices instead, from which BS 7288 was absent - whether by design or error we still don't know (although I still suspect it was in error).


   - Andy.

" SRCDS are only intended to supplementary protection downstream of the SRCD. SRCDs are intended for use in circuits where the fault protection and additional protection are already assured upstream upstream of the SRCD".


So these devices can no longer be used for additional protection.

Surely such an interpretation defies common sense? Why on earth would a standard for 30mA RCD sockets intend to demand upstream 30mA RCD protection - it just isn't logical. Isn't it far more likely that the intention was simply to re-enforce the point that the device doesn't provide upstream protection (as would be commonly be needed these days - e.g. for T&E concealed in a wall) and that something got lost in translation from during the committeeitization of the prose?

 

So BS7671, crucially in the "selection and erection" section, removed BS7288 as "accepted devices"

I don't think that BS 7288 has been "removed" as such - before the 18th there wasn't a list of acceptable devices (some devices were mentioned elsewhere and had useful data provided for them, but as far as I can tell there was no implication that other devices couldn't be equally acceptable) - just some very specific performance requirements (e.g. rated ≤30mA and opening within 40ms at 5xI_Δn). Come the 18th the performance requirements disappeared (perhaps because some devices now need 250mA rather than 150mA to open within 40ms) and we just had a list of acceptable devices instead, from which BS 7288 was absent - whether by design or error we still don't know (although I still suspect it was in error).


   - Andy.