Had the EICR check today and a couple of things came up for me to resolve, one of which is the Earth cable to the mains power supply needs upgrading to 16mm - current 2x6mm. I've a chasing tool and thinking it's worth the minor hassle of burying the cable. I'm assuming it still needs to be trunked, i.e. chase out, insert trunking insert cable, fit trunking top and then filler. I know there's regs regarding the routes taken by buried power cables, but I'm assuming these don't apply to just an earth wire? Can I just take the shortest route?
NB I can't find any specific exceptions for earth cables, although I note that you can run cables through non-safe zones if the cable is protected by earthed trunking, which would suggest the reg only applies to live cables. However, if it does not, any suggestions on how I can route the main earth cable here? The electricity meter is in a box underneath the window - the top of the box is accessible by removing the window sill so the simplest route for earth cable is shown in red.
Straight through the wall on the right of the CCU, drill it from outside to inside and you will be able to conceal the cable nicely. Clip the cable down the wall to the meter box and off you go.
I'd rather run it in surface mounted conduits inside than do that! Not happy at all at the thought of 6ft of bright yellow/green cable winding down the wall right next to my front door!
Straight out the back of the consumer unit down and round into the bottom of the meter box in conduit?
Out of the top of the Meter box, through the side of the surrounding plywood box and into the wall cavity at the front - from there somehow they get into the wall cavity on the Consumer Unit wall and into the back of the Consumer Unit. The existing earth follows the same route. I may be able to pull through the upgraded cable, and I'll certainly give it a go, but I think it unlikely to be successful.
Can you tell us the earthing system, TT, TNS, PME? If it's TNC chances are 2x6mm will be ok but more info is needed.
That photo completely changes my opinion, run the cable down the wall in the corner and through the corner of the cill as your red line suggests.
So I got lucky - turned out there was only one pinch point with the original cables - where they run through a hole in the side of the plywood box and into the cavity and I could get my hands in to push through, so it took a lot of cursing and a few drops of blood, but I was able to tie the 16mm to one of the old 6mm's and draw it through. Checked with my sparkie and he's happy with that.