Why should we use 10mm T&E for shower cable when the wire going from the terminal block to the heating coil in the shower otself is only around 5mm conductor?
Why use 10mm conductor ?
- Thread starter tilla tech
- Start date
Sponsored Links
Because the the voltage drop in a cable is proportional to it's length (amongst other things), and the interconnects inside the shower unit are very short so they don't need to be so fat.
We get the same question about gas pipes. Why does a combi need 22mm or 28mm copper when the inlet connection is 15mm? Same sort of answer, pressure being analogous to voltage.
Cheers, Mike
We get the same question about gas pipes. Why does a combi need 22mm or 28mm copper when the inlet connection is 15mm? Same sort of answer, pressure being analogous to voltage.
Cheers, Mike
As sparks, we are advised to follow BS7671 with regard to current carrying capacity and voltage drop. Presumably the manufacturers of electric showers have their own set of BS numbers to adhere to, and who knows, next time they're updated they might call for thicker wiring... (as things stand, perhaps the shower unit itself is the weakpoint in the system: I for one have come across such wiring 'burning out' on at least one occasion).
The other thing which varies greatly is the ability of the conductor to dissipate heat, an installed conductor may be unable to do this as effectively as a conductor within the shower unit. The conductors within the shower unit may have a higher temperature rating and i.e. have a silicone sheath too.
Sponsored Links
- Joined
- 11 Jan 2004
- Messages
- 42,729
- Reaction score
- 2,632
- Country
Same thing in a CU. A 100A RCD may be fed by internal wiring <25mm2.
- Joined
- 18 Nov 2006
- Messages
- 4
- Reaction score
- 0
- Country
No reason 2 at all. But ya may wanna upgrade shower in future. Fancy running that cable in again? Jusy damn hard work!
R
ryanj
Me Again lol said:
That is incredibly stupid advice to give out. The regulations are there for a reason.
As for the reasons, they've been covered perfectly already.
- Joined
- 18 Nov 2006
- Messages
- 4
- Reaction score
- 0
- Country
ryan, you ever read the regs? have any understanding of electricity? If a shower has x mm cable, it hopefully has been safety tested, to withstand appropriate current. Not saying this is alwaysthe case, but if so, well, do the maths.
M
Moz
throw the iron in ..
The reason for the reg is to minimize heat and reduce fire risk. We don't want excessive heat in remote places in our houses near to, say, old insulation and sawdust, etc, so big cables are needed. Heat from a cable inside a non inflammable shower unit with a copper tank heating up like a kettle, isn't a problem.
My tuppence worth....
My tuppence worth....
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
