buzbar

[saleem]

In a split load CU, normally some mcb,s are on rcd side which need protection and others are on non rcd side. Phase and neutral leads are crossed from main incomer to rcd.

What about the busbar, is it supposed to be used as one piece or cut accordingly.

My sparky has done second fix today.

I have noticed four blanks are inserted in between rcd and non rcd side but buzbar is as one piece. Is it suppose to be like this. Board was supplied by me, MEM 2000 AD. Normally main switch is on right side but on mem boards it is on left side.

I had asked sparky to swap them over so cables comming from left underneath does not have to cross over the main tails, as meter was on right hand side. I was told by wholesaler that it could be switch over. Sparky says it can't be.

Swa cable for garage also comes from underneath which need glands. Meter tails are in way. Can we gland metal adaptable box below tails and use trunking to go underneath tails into CU.

 

[ColJack]

pictures?

 

[Taylortwocities]

You should have let your spark supply the CU (as advised previously)!

In a split load board there should be two neutral busbars. It wont work otherwise.
I am not familiar with MEM but swopping round the orientation of main switches is a problem as the live busbar then comes out of the wrong terminal at the bottom. This is an issue with WYLEX as the busbar into the main switch/RCD is offset. Some main switches & RCDs are marked L & N so u cannot swop round the feeds.
Some RCDs do care which way round the feed is as the test circuit runs of the phase side.

 

[JohnD]

The MEM2000AD (but not the MEM 2000) has the main switch on the left. The main switch (or the RCD if an RCD is used as main switch) is a special left-handed one, where N is the LHS terminal and P is the RHS terminal.

On a split-load, the CU is supplied with solid copper connectors to go from the bottom of the main switch to the LHS N block and the top of the RCD. The split-load RCD is meant to go at the RHS of the enclosure, and has a RHS N terminal and an LHS P terminal. If you changed it to a right-hand incomer, the main switch and the solid connectors would not be right. The MEM RCDs have a white Functional earth, this would not work correctly if N went through the P terminals. The CU is also supplied with solid copper conductors to go from the RCD to the RHS N block.

However, the MEM2000AD busbar can be snapped to length to suit whatever your Split configuration is (i.e. if you have a 12-way, you can snap it to an 11/1; or a 10/2;or an 8/4 or a 6/6 configuration. You have to leave a gap in the middle so the two halves can't touch. If it not snapped then the RCD protection would not work since the current would flow from the LHS main switch to all the MCBs, including those on the right.

Your electrician might not be familiar with snapping the busbar, it is an unusual feature of the 2000AD range. Did it come with the installation instructions?

Other brands have a fixed Busbar, and can only be used in the configuration they have been manufactured for, so it would in most cases be wrong to cut the busbar. MEM 2000AD are as far as I know unique in being able to do that, so it is not surprising your electrician is not used to the idea.

If you are using RCBOs it is done differently.

As for leading in your SWA, I am assuming you have an insulated, not a metalclad, CU, so it would be usual to terminate the SWA in a steel adaptable box adjacent to the CU, with the correct gland, earth banjo etc, and lead the wires into the CU through a cutout or through the back if the CU is spaced off the wall enough. The cables in through the back is, I think, neater. If it is spaced off by, say, 50mm, then there should be no difficulty crossing cables.

The MEM is a very good brand, but you can see why electricians generally prefer to supply and fit the equipment they are familar with.

 

[Lectrician]

On that model MEM, the main switch is on the far left, and the RCD on the far right.

The busbar is complete length, and you use two pairs of pliers to 'snap' the the busbar at the required length, removing the small section of busbar between the two upright busbar stabs.

You cant move the position of the incommer and RCD, for reasons stated above.