cable through outside wall

[bengasman]

Hot water cylinder on third level in split level house with sanded and varnished floorboards and the boiler controls and three port valve in the extension.
The cylinder needs a new cable as it is currently wired with the wrong cable.
The only relatively easy way is to go through the wall and along the outside to the extension.
Is it acceptable to just run this in conduit or do I need to do more?

 

[Spark123]

You can run conduit outside yes, make sure any joints are properly sealed. Is there any chance of it being hit? If there is then you might need to use galvo. As for ergonomics tho

 

[bengasman]

private garden, no access other than through house and i can run it over 2 metres high.
just was not sure about running flex along outside wall as you don't find a lot of solid 5 core plus earth.
always like to do things as much by the book as possible

 

[Taylortwocities]

The rule about cable is that it must be the right size to carry the design current.

There is nothing to stop someone running 3 core flex to extend a circuit inside a building (eg, under floor, up walls, etc). It does not need to be solid conductor.
It does need to meet the current-carrying details AND it must have an earthed conductor. (aka CPC - Circuit Protective Conductor)

Therefore you'll be OK to run 5-core flex in conduit outside.

 

[bengasman]

i rarely bother to calculate cable sizes as i prefer to err on the size of caution and also like mechanical strength.
another reason to use bigger than strictly needed is not to get into trouble if someone decides to stick insulation in and has no idea that that has an effect on cables.
for a threeport valve like this one, i usually take 1mm2 if not 1.5

thanks for the help guys