Flex connection to bathroom towel rail

[Jolly Roger]

Hi,

I have a "summer heating element" to connect to a new towel rail in the bathroom. The supply (via a timer and 30mA RCD fused spur) is the other side of the wall on which the rail is mounted in a bedroom cupboard. Convention would say sink a single gang box in the wall by the rail and use a flex oulet. Cutting through a tile is messy and it would be far simpler to just pass the flex through the wall (just drill a hole a little larger to comforatbly accept the cable, seal round the flex) and connect up on the other side. To me it seems safer as there are NO connections whatsoever in the bathroom and if the heater needed replacing it could be disconnected in the cupboad.

Anyone care to comment on whether the simpler arrangement is valid?

 

[kai]

This method could be used provided that ALL the following are adhered to.

The cable is secured by the cord grip of the Fused Spur in the bedroom.

The hole in the wall is lined with a length of plastic conduit grouted into the hole.

The cable is adequate for the design current of the heater, after applying de-rating correction for the conduit run.

The earth loop impedance at the heater terminals is low enough to be compatible with the fuse in the spur unit. (normally a 13amp fuse is used for a heater, and Total ELI must be less than two and a half ohms total)

 

[GaryMo]

The earth loop impedance at the heater terminals is low enough to be compatible with the fuse in the spur unit. (normally a 13amp fuse is used for a heater, and Total ELI must be less than two and a half ohms total)

Max permitted Zs for a 13A BS1362 (5s disconnection) is 4ohms, 80% rule of thumb brings this down to 3.2ohms

 

[Jolly Roger]

Many thanks for the replies. I think all 4 criteria can be met, though would need to check the ELI.
I can see I'll end up with the flex outlet on the wall in the bathroom as it meets convention - it just seemed a chance to remove the connection point out of the room. Also, the mess involved in making a large hole to accept the conduit is probably about the same a chasing a box in.