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Consumer units and PME

I have been trying to change over my old mem consumer unit for a new Mk split load one and am having problems with the RCD side of the unit. I have put both the house ring mains and the garage sockets on the RCD side and every time I switch any of the mcb's on the RCD side on it trips. I assume the problem is connected to the PME earthing (or my lack of understanding of PME ) as I have isolated each of the ring mains and got a good insulation test reading on both.

Can anyone tell me where I am going wrong.

thanks John

Reply to
John M
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check that you have removed the link between the protected side and the unprotected side on the neutral bar, and that you have terminated the neutrals to the correct side as well. Larry

Reply to
LOZ34

I had the same problem - in my case, I'd crossed one of the neutrals, thus unbalancing it all. Make sure that on the RCB side, that the neutrals are all together on one of the blocks of connectors along the top, and that these are seperate from the neutrals on the non-RCB side, which will be altogether on their OWN block of connectors.

What you don't want to do is have neutrals for RCB circuits connected with neutrals for non-RCB circuits.

I'm sure it said this in the instructions, which I read afterwards.

Regards Paul

Reply to
Paul Boakes

I don't think it's a PME issue.

There is a link between the two neutral bus bars - one bus bar to be used for non-RCD-side circuits, the other for RCD-side. The link must be removed.

Also, the neutral wires from the RCD and non RCD circuits must terminate to the correct bus bar.

Other than that, have a look for any earth to neutral shorts....

.andy

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Reply to
Andy Hall

Thanks guys,

Looks like you have nailed it on the head. I saw in the instructions in the box that the cu should be set up for split load by reconfiguring the nuetral links, When I got the cu it came with the the RCD fitted and was configured for two nuetral bars correctly. The problem here is with my brain. I had one of the neutrals from the non RCD side on the RCD nuetral bar. thanks

John

Reply to
John M

Don't worry John, we all do it. I did in front of the customer once and spent 20 mins looking desperate. !!

Dave

Reply to
Dave Stanton

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