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Shower with no RCD or supplementary bonding

MrJack96

I have been round to a relatives flat and seen he has an old Wylex board with MCBs. His bathroom has no supplementary bonding from what I can see and no RCD protection for his electric shower. how potentially dangerous is this? I know the circuits are fairly short and can see main bonding in place Can only really think if the R2 values are low enough touch voltages should end up being kept low? 

 

 

 

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    If the extraneous conductive parts are caught by the MPB then during a fault of negligible impedance, the fault current is considered to be confined to the cpc and the fault current magnitude being the current required to disconnect the CPD in 5s or +0.1s in the case of mcbs. The actual current may be more but the trade off is that disconnection will be quicker. The touch voltage experienced can therefore be assessed to be the voltage drop along the cpc referenced to the MET.

    Similarly when supplementary bonding is in place, then all of the fault current required to disconnect the CPD is considered to be confined to the supplementary bond. The Ut being apparent across it.

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    If the extraneous conductive parts are caught by the MPB then during a fault of negligible impedance, the fault current is considered to be confined to the cpc and the fault current magnitude being the current required to disconnect the CPD in 5s or +0.1s in the case of mcbs. The actual current may be more but the trade off is that disconnection will be quicker. The touch voltage experienced can therefore be assessed to be the voltage drop along the cpc referenced to the MET.

    Similarly when supplementary bonding is in place, then all of the fault current required to disconnect the CPD is considered to be confined to the supplementary bond. The Ut being apparent across it.

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