TT System 100ma S Type Housing

[westward10]

Not aware that either the 16th or 17th edition mention "incorporating overcurrent protection" in relation to RCDs?
My understanding, is that an RCD incorporating overcurrent protection is an RCBO.

I slightly reworded Reg 411.5.1 to save it being "wordy".
Note 2 of said reg says where an rcd is used for fault protection the circuit should also incorporate an overcurrent protective device. So this could be an rcbo or mcb and separate rcd.

 

[saspm]

I have called the Niceic help line today as to weather a 100mA S Type RCD is required on the TT system and can confirm that:

In my case:

If the 16th edition board is converted to a 17th board using the original plastic casing it will not require a 100ma time delayed RCD, as long as the meter tails are short enough. This also applies to the new metal consumer unit.

Thanks for everyone's input