I like the Toughbuilt stuff myself. Check out this thread:
Tool belts .....anyone a fan?? - https://www.electriciansforums.co.uk/threads/tool-belts-anyone-a-fan.141536/
If this box is to be 'recessed' into the ground, I suggest extending the cable using a resin-sealed joint instead, and burying it at a suitable depth, taking into account the location.
The 3rd contact on the battery is likely to be for a temperature sensor in the battery pack which will stop the charger fast charging when it gets too warm.
If you're still using NiMH batteries, I'd be inclined to look for a new Li-Ion tool set with batteries and charger at a good price.
There's no requirement for an additional consumer unit. For small sheds with minimal loading and no bonding requirements, a 20A RCD protected supply to the sockets with a 3A FCU for the lights is my default suggestion. Sometimes I'll add a 20A DP switch where the supply enters the shed, but not...
I've done that too, using the nice rectangular MK junction boxes. But how do you sleeve the cpc?
MK 30A 3 Terminal White Junction Box | Departments | DIY at B&Q - https://www.diy.com/departments/mk-30a-3-terminal-white-junction-box/189593_BQ.prd
I generally like the BG outdoor stuff, but the FCU is awful. I used one once, but the flexible membrane eventually goes sticky and opaque. Plus, you can't replace the fuse without taking the whole thing apart.
I now take one of their single sockets and replace the socket plate with a FCU one.
A pic of the wiring inside the new CU might help (or might not). Also a pic of the wiring to the RCBO.
Pretty hard to diagnose remotely without a full set of tests.
New parts for 6mm². They're just a little bit bigger all round then the existing ones. If you saw one by itself, you might not notice that it was any different.
I'd agree that the JCC Skypacks are a good fitting. Fitted a load of these recently. 5ft 'doubles', although they're the same size as 'singles' but with two strips of LEDs inside instead of one. There's a range available at different light outputs and prices:
JCC Lighting JC71707 Skypack White...
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