17th edition dual rcd consumer units

[kenny james]

may sound a stupid question to some sparks but one thing that puzzles me over dual rcd consumer units is the following points : bs7671 says all new boards must be fitted with dual rcd consumer units to comply to regs so all circuits are protected. a typical example is our local council is contracting the electrical work out on a tender to install new d/b units in there properties they have stipulated that the lights and boiler systems must not be rcd protected. does this mean the boards are not bs7671 regs as some of the circuits eg lights are not rcd protected and the boiler system?. hope somebody can enlighten me on this. as i am getting more confused the more d/b units i see that are suppose to be to bs7671 regs! thanks.

 

[telectrix]

if the lights and boiler cables are surface mounted, then there's no need for RCD protection. knowing councils, it will all be surface in mini trunking.

 

[alanl]

I think manufacturers are stretching the rules when they say '17th Ed. CU'. To comply fully, each circuit must be on a separate RCD (or not RCD protected as necessary), so to ensure compliance a CU with RCBOs would be the only way.

I had this chat at my last assessment, and he agreed that a dual RCD CU does not comply fully, though as with many of the Regs, it can be argued that it may comply if circuits are segregrated correctly.
Alan.

 

[Risteard]

bs7671 says all new boards must be fitted with dual rcd consumer units to comply to regs so all circuits are protected.

BS 7671 does not state that a distribution board must have two RCDs in it. Nor does it state that every circuit in a domestic premises must have RCD protection.

 

[SirKit Breaker]

Most circuits in domestic require RCD protection. But there are exceptions, and they are listed in the BRB.

Cheers............Howard.

 

[Deleted member 9648]

The relevant section is 314.1 (i) .....one way of complying with this where circuits require RCD protection is to use more than one RCD so that in the event of tripping not all circuits are lost....Hence '17th edition boards'...There are other ways of complying with 314 such as RCBO's.

 

[SimpleSimon]

If it's surfaced mounted or is to be buried with earthed metallic conduit installed and sufficient mechanical protection against nails and screws than it's fine.
Like Howard said it's in the BGB

 

[D Skelton]

I think manufacturers are stretching the rules when they say '17th Ed. CU'. To comply fully, each circuit must be on a separate RCD (or not RCD protected as necessary), so to ensure compliance a CU with RCBOs would be the only way. I had this chat at my last assessment, and he agreed that a dual RCD CU does not comply fully, though as with many of the Regs, it can be argued that it may comply if circuits are segregrated correctly. Alan.

100% correct

 

[GLENNSPARK]

My boss is into putting smokes and heats on their own circuit with RCBO. I dont like this and would pull a feed of a 3 plate but it aint my place to say owt..........

 

[telectrix]

i feed smokes from lighting. too easy for mr. numpty to turn off RCBO when wifey burns the dinner. if his lights go out as well, he'll soon turn it back on.

 

[GLENNSPARK]

i feed smokes from lighting. too easy for mr. numpty to turn off RCBO when wifey burns the dinner. if his lights go out as well, he'll soon turn it back on.

And i think it went "if the lights stay on you know its salad day"..lol.......:yesnod: