On top, or underneath - any preferences?

[ban-all-sheds]

Incoming and outgoing cables I mean.

Obviously for devices in a CU with a busbar, there is little choice, but if free from that constraint, is there any reason to prefer the incoming live conductors to go into the top, or the bottom of switches, MCBs, RCDs etc?

 

[securespark]

If I could CHOOSE, then it would be whatever was convenient for wiring the switch etc.

If I wire stand-alone iso's or RCD's etc, then I follow the same convention as the CU in the property - usually incoming TOP and outgoing BOTTOM.

 

[ban-all-sheds]

As you've done with yours, IIRC....