Shower circuit design.

Chris Pearson: 
 

Sparkingchip: 
I presume  @davezawadi (David Stone) will tell me that despite being unusable because the circuit breaker tripped if you turned more than one hot plate on along with the oven, it fully complied with the Wiring Regulations and I should not have coded it a a C2 in the EICR.

I shall too!

I am not sure that BS 7671 says that you have to provide enough power. The circuit was perfectly safe, but the unwanted tripping would be a real nuisance. The circuit complied with 433.1.1 when it was erected. 133.2 may be relevant, but it certainly wouldn't merit more than C3. Overall, non-compliance is not obvious, so no code from me.

So yes, 133.2 is where I'm going … but which piece of equipment is not selected and erected in accordance with this?

I'm going for TWO possible non-compliances  here … one of which warrants either C2 or FI (take your pick, I don't have enough information to choose without seeing the installation):

• Shower not selected and erected to prevent overheating of OCPD in use (severity dependent on adjacent OCPD loading factor). This is C2 or FI.
• Then there is the issue of OCPD not selected according to manufacturer's requirements for protection against overload current (given it's a concentric heating element device) - although because In of the OCPD is lower than that required by the shower manufacturer, this can only be a C3 - and I guess this is where David Z is coming from.

Chris Pearson: 
 

Sparkingchip: 
I presume  @davezawadi (David Stone) will tell me that despite being unusable because the circuit breaker tripped if you turned more than one hot plate on along with the oven, it fully complied with the Wiring Regulations and I should not have coded it a a C2 in the EICR.

I shall too!

I am not sure that BS 7671 says that you have to provide enough power. The circuit was perfectly safe, but the unwanted tripping would be a real nuisance. The circuit complied with 433.1.1 when it was erected. 133.2 may be relevant, but it certainly wouldn't merit more than C3. Overall, non-compliance is not obvious, so no code from me.

So yes, 133.2 is where I'm going … but which piece of equipment is not selected and erected in accordance with this?

I'm going for TWO possible non-compliances  here … one of which warrants either C2 or FI (take your pick, I don't have enough information to choose without seeing the installation):

• Shower not selected and erected to prevent overheating of OCPD in use (severity dependent on adjacent OCPD loading factor). This is C2 or FI.
• Then there is the issue of OCPD not selected according to manufacturer's requirements for protection against overload current (given it's a concentric heating element device) - although because In of the OCPD is lower than that required by the shower manufacturer, this can only be a C3 - and I guess this is where David Z is coming from.