Correct MCB/RCBO sizing

[diyhell]

I've got a length of protected cable running through the cellar then under concrete for around 15m from the CU to my garage.

It's 1.5mm2 (why the previous owner didn't fit 2.5 or 4mm2 I don't know) so I understand that a 20amp MCB/RCBO is going to be too high. Question is, what's a safe rating for it?

It'll get replaced in time but for the moment it'd be handy for a bit of light and power.

 

[unphased_spark]

not an adequate sizing for a power circuit minimum requirement is 2.5mm sq would only be suitable for a lighting circuit

 

[plugwash]

assuming its pvc (and its bloody hard to tell the difference between pvc and xple once installed so we assume its pvc to be safe) 16A is the maximum breaker you can use (the run is short enough that volt drop isn't a problem)

this should be enough to run a light and any one appliance at a time and more than one low current appliance

 

[securespark]

As long as you limit the current drawn by the SWA to 13A, you can run appliances from it.

 

[ban-all-sheds]

It's 1.5mm2 (why the previous owner didn't fit 2.5 or 4mm2 I don't know)

It was AdamW's professor - thinks that all cables are 13A.

 

[diyhell]

Many thanks.