Just to say that I not a fully qualified spark, but I still have a few issues issues with the install / wiring of this old junction box, that triggers my OCD ?.
Firstly, if you look in the bottom corners of the so called IP rated back box, you will see some rust staining ( not from plastic I hear you say ).
But check out where the screws are attaching the box to the wall !.
The back box has been drilled of course, but in turn this has completely compromising the IP rating of the box.
The box has been attached to the wall ( likely without any silicone applied to the rear surface of the back box first.
As a result, water has been allowed to enter the back box via this route.
This is clearly evident as the retaining screws have rusted ( hence the rusty water stains inside the box ).
I am also willing to bet that there has been no water drain hole drilled in one of the bottom back corners of the back box either for drainage ( should the box IP integrity become compromised ).
Top entry via any gland is never a good option either, where possible enter from the side or even better, from the bottom and include a drip loop into the incoming / out going cables.
This will allow water to run down the outside of the cable and then drip from the loop made in the bottom of cable.
The choc block strip looks a little undersized, and the multi stranded single conductors, looks like they have been twisted together and then inserted into the choc block.
No cable crimping ferrules used back then of course.
Over time the terminal screws in the choc block have become loose and heat / burning has commenced.
Today, there are better quality alternatives for both back boxes and terminal connectors.
A wiska box / crimping ferrules and Wago connectors would be a big improvement over the previous install.
The earth / CPC connections don’t look right to me either ?.
Two single conductors are sharing the same terminal connector in the choc box ( okay ) but we then have another single earth / CPC conductor living on its own in the terminal strip next door ?.
I can’t see a jump across the back, so how has the earth continuity been maintained here ??.
Of course we are unable to see the whole install.
Maybe a qualified person can correct me if I wrong here ?.
Some wall boxes ( even new units ) come pre wired with a short length of appropriate sized cable, from the manufacturer.
They do not want you to have access to the internals.
Therefore you have no alternative but to use a junction box to connect the wall box to the supply cable.
It’s really is surprising that the wall boxes was still working TBH.
Is this wall box protected by suitably rated breaker in the CU or by a stand alone CU.
Strange, as I would have thought that this would have been intermittently tripping before reaching this stage ?.
It sounds like you intend to update your wall 13 year old box in the not too distant future regardless.
The regs have changed regarding the installation of wall boxes now, so you may need some upgrades to your home electrics when you do the switch over.
