If that is the case, how do you propose I connect it up in light of the following rccb terminal layout:
There is a neutral connection on the top of the rccb. On the bottom there are two live terminal pins (which plug directly into the CU busbar) and a neutral connection
The unit is a Crabtree split-load rccb part no 363/s100
What would you do?
Cheers
On 1 Mar 2007 04:15:58 -0800, snipped-for-privacy@mailinator.com mused:
Well, I'd fix it using m skills as an electrician to test everything and make 300% sure everything is actually the right polarity.
Simple really, but you haven't filled me with confidence so I'm guessing you haven't been through and tested everything?
Are you missing the two neutral buss bars? One is used for the non RCD protected side, the other for the RCD protected. And both neutrals from say a ring must go to the correct one.
I'd switch everything off (including MCBs) and check the resistance between the two bars. It should be near infinite.
snipped-for-privacy@mailinator.com explained on 28/02/2007 :
My understanding of it suggests that nothing needs to be connected to the output of the RCD, for it to be tripped by pressing the test button
- all it should need is a L & N on the input.
With the 100mA RCD switched off, what voltage do you read between the top right N connection and the main incoming live?
Adam
How are you getting two pins from the live busbar into one terminal on the Rcd? I think we really need a photograph. to make sense of what you have
On 1 Mar 2007 11:37:22 -0800, "cynic" mused:
On the bottom of the RCD are two plug in pins. One takes the power from the end of the non-RCD'd busbar and the other pin plugs into the RCD protected busbar. The busbar is split behind the RCD.
I'm even more confused now. I thought it was the mains incoming time delayed RCD which was tripping. In this case I would expect the L & N meter tails to go into the top two 100mA RCD terminals. From the bottom I'd expect there to be a Live connection to the L of the 30mA RCD and a connection to the 100mA protected busbar section for lighting and fixed equipment. The (other bottom terminal) Neutral output from the 100mA RCD would connect to the input N of the 30mA RCD and to the 100mA protected Neutral bar. The 30mA (fast) RCD would have its own bit of busbar for socket outlets and similar together with its own bit of Neutral bar for these associated circuits. If two or maybe three 100mA RCDs are showing the same failure to trip by their own test button it does point to either live or neutral connections being to the "wrong" end of the RCD i.e. diagonally across corner connected. This would not give a leakage path simulation by the button but would give a trip by normal current flow. We need pictures!
On 2 Mar 2007 23:04:21 -0800, "cynic" mused:
Yeah, actually, I'm confused now!
Pictures required.
Revisiting this post - are you saying that the two RCDs have the meter tail neutral into them both in parallel but one Rcd (the 100mA one) has the live meter tail feeding it and the output of the live side goes to the 30mA RCD and the 100mA protected bus bar? If I've read you right the 30mA protected circuits take the live current through the
100mA AND the 30mA RCDs but the neutral return current passes through the 30mA and NOT the 100mA unit. This means there is bound to be an imbalance in the 100mA RCD if any current is drawn through the 30mA RCD protected circuits and the 100mA RCD will trip as soon as a load is switched on. In short it aint wired up right!
Just an update on this for those interested.
The third rccb did actually work thus proving the previous two to be at fault, which is a first indeed! (Live and learn eh? - Not to use Crabtree again that is!)
Thanks for your contributions in trying to work this out. For the posts questioning my abilities I know you can't assume knowledge automatically, but believe me when I say that I did test and check everything before running to this newsgroup as a last resort. It's nice that some people actually took that as read...
On Wednesday, 28 February 2007 17:08:04 UTC, snipped-for-privacy@mailinator.com wro te:
I am having exactly the same problem, wondered if you have solved it. I? ??ve replaced the split rcd unit But with no joy. My unit is split on a stack one above the other With the b ottom rcd working perfectly. The earth reading is 45 ohms well within the regs. All connections have bee n copied from a split none stacked board. Any help gratefully received.
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