shower cable size

[oohthatslive!!]

got a 10.5 kw shower to fit.comes in at 45.65 amps. looking at the on site guide for CCC. 10mm cable ref method 4 says it will carry 43 amps. table 6E1.
so am i looking at the correct table? or can i assume that some
of the cable will be buried in the wall and some will be clipped
direct and so it will up the CCC to a sufficient amount?

 

[davy_owen_88]

Firstly, the 10.5kW rating is for 240V not 230 so it will actually draw 43.75A @ 240V and less if your voltage is lower.

10mm² t&e clipped direct can take 64A. 47A when installed directly in an insulated wall and 44A when in conduit in insulated wall. *From table 4D5A of BS7671.

If you give is a run down of all the environments the cable will run through then we can tell you for definite whether 10mm² will do.

 

[oohthatslive!!]

u mean less if the voltage is higher? cable runs about 3 metres ref 4 and then clipped method 1 for about 6 metres

 

[ricicle]

u mean less if the voltage is higher?

Do we have to go back to basic Ohm's law......

For a fixed resistive load (eg a heating element), it will draw more current at 240V than at 230V

Check the rating plate to see if the Kw rating is at 240V or 230V

 

[GaryMo]

u mean less if the voltage is higher?

Do we have to go back to basic Ohm's law......

For a fixed resistive load (eg a heating element), it will draw more current at 240V than at 230V

10500/240=43.75A
10500/230=45.65A

 

[davy_owen_88]

10500/240=43.75A
10500/230=45.65A

No.

A shower that is rated at 10.5kW @ 240V has a fixed resistance of: 240v / 43.75A = 5.49 ohms.
If you run that same shower at 230v: 230v / 5.49ohms = 41.9A or 9.6kW.

 

[GaryMo]

Cheers Davy, guess I should take my blinkers of once in a while!

 

[ricicle]

Which is why you have to see if the shower power rating is based on 230 or 240V to determine it's current draw

 

[GaryMo]

Which is why you have to see if the shower power rating is based on 230 or 240V to determine it's current draw

Quite

 

[davy_owen_88]

Which is why you have to see if the shower power rating is based on 230 or 240V to determine it's current draw

Have you seen any 11.4kW showers ricicle?

 

[ricicle]

Which is why you have to see if the shower power rating is based on 230 or 240V to determine it's current draw

Have you seen any 11.4kW showers ricicle?

Not lately Monsieur Davy