EICR on a Sunday

[Wonderwall]

I simply tell the customer they are paying for a report, as I find it. I leave it fully confident that they can get another sparky in if they wish to verify any faults I have highlighted.

 

[Andy78]

I fitted 3 lengths of 2.5mm butyl flex to immersion heaters yesterday. I'll let myself off over sizing the cable though as they were 4kW elements. Now that would have been pushing 1.5mm flex to its limit, but a 3kW element certainly wouldn't.

 

[Lucien Nunes]

I don't see how you can consider that to be running it close? It is only 4/5 of the rated current of the cable

Indeed. For anyone worried about using a cable near rating, remember that the heat dissipated is proportional to the square of the current, in this case 16/25 or about 64% of the permitted temperature rise.

I can see the point in standardising on 2.5 for 3kW aircon loads though as the voltage drop during compressor starting is critical and might often be a more onerous requirement than CCC.

 

[Skimpy Wan]

Indeed. For anyone worried about using a cable near rating, remember that the heat dissipated is proportional to the square of the current, in this case 16/25 or about 64% of the permitted temperature rise.

Please can you explain this one to me as I've not heard / been taught this calculation / consideration .... sorry if I'm being dumb!

p.s.Can we not just say heat resistant flex rather than butyl ... its so much easier to spell!!:tounge_smile:

 

[Andy78]

Please can you explain this one to me as I've not heard / been taught this calculation / consideration .... sorry if I'm being dumb!

p.s.Can we not just say heat resistant flex rather than butyl ... its so much easier to spell!!:tounge_smile:

Butyl has enhanced heat resistance over standard duty flex, but not all heat resistant flex is butyl. Butyl is rubber HR flex but you can get PVC HR flex too.

 

[Lucien Nunes]

Please can you explain this one to me

P=I²R

This P being the one dissipated in the cable, not the load.

 

[Skimpy Wan]

Cheers.

I now need to learn to spell butyl correctly then! Lol! Only every used "heat resistant flex" from wholesalers. I'll have a look into when butyl would be prudent in comparison to heat res. flex.

I didn't notice the link between P = I2 x R, so thanks for clarifying for me