Extending main earth

[very_pointy_ears]

I've tried searching but haven't found a definitive answer.

We have a separate earth connector coming in from the supply and going into an earth block from where all other earths are taken. The supply cables come in through the wall to the left of the CU:

As our supply comes in via overhead cables I'd like to replace the isolator that's to the right of the meter with a metal enclosure containing the isolator and a type 1+2+3 SPD. As you can see from the picture, there is nowhere else the SPD could go. I was thinking of one of these:

https://www.surgedevices.co.uk/prod...with-window-indication-and-pluggable-modules/

However, the supplier's earth cable will not reach down there, and it's a relatively long way from the earth block to where the SPD would have to go. I realise that you are allowed up to a metre to an SPD but it's not ideal, and would reduce the effectiveness of the device.

Is it acceptable to extend the supplier's earth cable such that the main earth comes in through the wall and goes straight down to the SPD, and then back up to the connector block above the CU?

 

[flameport]

Yes

 

[very_pointy_ears]

Yes

Excellent, thank you.

I was thinking of using a smaller earth block to connect on another length of cable. I wasn't sure whether the supplier's earth had to be one continuous unbroken cable to the main earthing point.