This is totally hypothetical - but I was wondering...
Never seen the inside of a split load CU, except on google.
How is the L-flylead taken from the main switch (Live, Load side) to the RCD (Live, Supply side)?
Is it just inserted into the main switch on top of the non RCD busbar? Or is there a special terminal on the busbar?
Don't know why I thought of this - but my curiosity will not rest now.
Depends on the manufacturer. There is always a flylead invloved (or a sleeved solid copper link). Are you asking about dual RCD CUs?
Hi Adam - no single RCD units. Saw one the other day in a flat - and started wondering... I think this was a GE unit.
On many its just a fly lead with a crimped on tab at the end - it shares the terminal with the bus bar.
Thanks John - I have not seen one close enough...
Just out of interest - how would you convert one to dual RCD? Is it viable to stick the tabbed flylead in the top with the incomer tail?
Have a think about that. Where would the main switch be?
You would need another RCD and flylead and need to add that in addition to the main switch if you wanted to retain a single point of switching. If you don't need a single switch for the CU (say have one for the installation elsewhere) then you could do as you suggest.
Note also you would need to pay attention to how the neutral busbars are wired if you want to retain any non RCD ways (a so called 17th edition "high integrity" CU)
Mine has a crimped double flylead out of the main switch into two RCDs. It has two bus bars, two neutral bars and an earth bar. You can have a third neutral bar if you want some none RCD ways and put a third bus bar in with the fly lead.
On the left IIRC... RCD was on the far right. GE board (never seen a GE before).
Hmm - good point - never thought of that!
Another interesting point - thanks John. I like these oddball exercises :)
Well if you need someone who looks oddball when exercising, I am your man ;-)
Oooim considerably rounder than yow....
Well this is the only photo I can find ATM
However this one is unusual as the incoming terminals to the RCDs are at the bottom. And in this case very badly terminated........
Hmm - that makes me feel better :|
In article , ARW writes
Quite apart from the appallingly bad installation, I've just noticed the live and neutral appear to be swapped on the lefthand RCD, which would make the second neutral busbar live...
The kink in the live terminal on the main incomer is um, "interesting". All the installer needed to do was to swap live and neutral over on that, which would have allowed him to use the busbar as-is.
Oh dear. Apart from the mixed up live/neutral and the kinked busbar (that's all just weird), it looks like any CU to me. Not sure mine looks so much different. What is so shocking about the installation ? Wires will always be crossing due to the circuit cables coming in at various places and having to reach a cross to the neutral and earth terminals - if you try to make them too neat you end up wanting to create right angles which is not a good idea ! And you always end up with a bit of a rats nest after a few changes to the original installation. Having said all that, I'm sure CUs in general could be better designed. Simon.
In article , sm_jamieson writes
Exposed busbar, unused fingers not trimmed or isolated
Looks fixed direct to wall, not a board (is a board mandatory under the regs?)
Cables enter on right, would have looked neater mounted on a board offset from the wall with cables coming in the rear
If I saw that on a job I'd rip it all out and start over.
When do you trim busbar fingers? It would make adding extra devices tricky later?
In article , Tim Watts writes
The terminals will take two fingers, so you just add another busbar if you need to fit more breakers, or replace it entirely.
Seems unnecessary to me. The bar will be covered under normal use and if you open a CU, you take precautions...
Now I agree there'd be no harm in "finger covers" but I've never seen them...
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.