CPC size for a shower

[Podooser]

I was told that one would need to add another cpc to bring up the size of the cpc in the 10mm2 T/E cable for a 9.2kw shower. Why would this be necessary?

 

[davy_owen_88]

Who told you this and are you sure they were not talking about supplementary bonding?

 

[Softus]

I was told that one would need to add another cpc to bring up the size of the cpc in the 10mm2 T/E cable for a 9.2kw shower. Why would this be necessary?

Probably to boost the ego of the person who fed you that heap of tripe.

 

[Podooser]

No he was not refering to bonding. He said as the cpc in the 10mm2 was only 4mm2 it would need to be added to for this application.

 

[securespark]

In the olden days, it was common to see a shower cable fed in alongside a 10 (or 6) milli earth which was connected to the shower cpc terminal. Some still do it, although I don't know why.

 

[Adam_151]

In the olden days, it was common to see a shower cable fed in alongside a 10 (or 6) milli earth which was connected to the shower cpc terminal. Some still do it, although I don't know why.

A few possibles

To hold down touch voltage in the days before local bonding?

To bring R1+R2 down in order to meet fast disconnection times on fuses? (0.48ohms after rule of thumb on 45A BS1361, compared to 0.85 on a B45 BSEN 60898)

To ensure that the cpc was thick enough to withstand the let through energy of the fuse without additional calculations, maybe designers speced it when it was necessary and the average spark just installed it everywhere just to be sure*... these days we have standard circuits in OSG to help

*think of the number of times these days when people arn't sure about SWA armour being sufficent for a CPC or not in specific cases