high integrity board layout - Is this Ok?

sensible · Feb 18, 2014

Hi,

I have looked inside my Dad's Consumer Unit and I noticed that it has 2 RCD's but also 1 RCBO. I've seen these before but on my dads I was worried that it has to many (live) terminations into the bottom of the main switch? It has the usual 2 live conductors (wires) in it each going off to there respective RCD's but also a small busbar coming out of it to feed the RCBO. Is this ok? Or should it just have one wire conductor (from main switch) going off to one of the RCD's and then that RCD could feed the other one, meaning its not such a squeeze under the main switch (would just have busbar and one wire)?

I've tried to have a look at typical layouts (for the live feeds) of a high integrity unit but cant see any pictures of that.

Thankyou everyone..

telectrix · Feb 18, 2014

usually, you'll find that the 2 tails feeding the 2 RCDs are both ferruled into 1 ferrule, this is normal practice as the board is designed to feed 2 RCDs and a busbar from the Lout of the main switch.

sensible · Feb 18, 2014

Thanks Telectrix,

So is this ok as it is, with 2 tails and a busbar coming from the Lout of the main switch? have you seen that before?

sensible · Feb 19, 2014

Just hoping someone knows? :smiley2:

Probably good for me to say what i think rather than just asking! It all fits in and the connection is screwed up tight and neither of the wire conductors or the busbar is loose so I would say its ok, I just wanted to know if this was wrong and if it should always be as Telectrix said with the use of a ferrule. It doesn't have a ferrule and I've seen other high integrity boards with both RCD's coming out of the Lout main switch as well (they just didn't happen to have any RCBO's)?

telectrix · Feb 19, 2014

the BG boards have 1 from the main switch to RCD1 and then looped to RCD2. other boards differ. if it's how the manufacturer designs it, then that's that.

SJD · Feb 19, 2014

It is quite normal to have 2 cables (to each of the RCDs) plus a busbar to any RCBOs. How the connections are made into the main switch depends on the quality/make of the consumer unit. Sometimes the 2 tails are made off into one ferrule, as Tel says; sometimes they appear to be separate but in fact are bonded together.

What is important is you get a good connection to all the connections (as loose connections are a common source of overheating), the manufacturer will normally specify to what torque these connections are tightened.