new circuit to RCD MainSwitch CU

[ianphilip007]

hey guys

i understand that a rcd main switch "should" not be installed (under BS7671) as segregation of circuits would be impossible and could result in danger/ inconvienience as all circuits would be deenergised in the event of a fault (reg 314). This arrangement (Front end RCD Main Sw) is very common though and not just on TT systems so when additions are made for example new shower circuit or cooker circuit or external lighting there is no way of applying reg 314 to the new circuits added. My view after reading the regs is that the new circuit obviously must comply with bs7671 and even though it is being connected to a consumer unit with a RCD Mainswitch, the C.U. and Mainswitch must be treated as retrospective installations under different regulations. I appreciate that this is not an ideal situation but i find it to be a common one within domestic insatallations. just wondered if anybody viewed it the same way or should i not be installing new circuits to C.U that have front end RCD due to reg 314 any thoughts ?

 

[IQ Electrical]

There is no problem whatsoever in doing as you're doing, other than the thousands of old ladies that fall down the stairs on nuisance tripping of front end RCD's

 

[somersetsparks]

I think you can only reccommend to the customer that they have rcbo's fitted or a board change, in my opinion, it is not dangerous electrically, but an inconvenience. If it is was old or disabled people then I would definately reccommend fitting RCBOs etc.

 

[ianphilip007]

yes there is that problem and i personally would not install a frontend RCD mainswitch but if its already there, what options are left , without fitting a new cu or total reconfiguration if possible of the old cu) if total compliance with BS7671 reg 314 is to be met.

 

[ianphilip007]

so somersparkes are you saying that you would you not add a new circuit to a C.U. with rcd mainswitch at all, Unless the customer agreed to have a new board fitted or Board reconfigured for RCBO's before hand ?

 

[ianphilip007]

or would you recommend a CU change or RCCBO and install the new circuit as required?

 

[somersetsparks]

No not at all, I would do the work and advise

 

[ianphilip007]

i thought that was what you meant somerspark, thats exactly my approach i advise of the possible problems and the benefits of a new dual RCD C.U.would bring, but then install the new circuit on the existing board. as i see it no other way arround. many thanks