Bus bar pins dont line up?

[Adam_151]

I thought this post was curious because like RF I was sure that the crank was right, and that the NHX was supposed to be compatable with the NSB.

So I went and got a couple of MCBs from the van and put them side by side... sure enough while they both would appear to fit the same 'U' shaped busbars sparkwright refers to (not confined to '16th edition boards' btw sparkwright, there are dual RCD splits which use this busbar type)

They don't seem to have the slot for the busbar prongs lining up. Sure enough with a straight busbar they do not sit level with one and another

A cranked busbar seems to bring it back into line. Not perfectly in this picture as its not a wylex busbar, just one that was to hand from the 'copper scrap' pile!

So it seems that in the NSB days a cranked busbar was required to get from the the main switch or RCD which had its pin terminal set further back to the MCBs. Now NSB has been replaced with NXH the MCBs have the pin terminal adjusted to be level with the main switch. So therefore one of the following is true

a) The cranked busbar is no longer required with NXH boards and you have been supplied the wrong busbar (This seems more likely)

OR

b) The NHX boards used a redesigned main switch with the terminal set even further back and the cranked busbar is still in use and you have the wrong main switch (This seems unlikely!)


Buts its going to cause trouble with adding breakers to existing boards... but I dare say wylex, like MEM, don't really care about that!.

NSB is with red busbar clip, NXH with white busbar clip

 

[AndyPRK]

I think that have moved the connection point on the NHX MCB's.

As I thought, your using the NHX MCB's, which are no good with that bus bar.

 

[confuzatron]

I think that have moved the connection point on the NHX MCB's.

As I thought, your using the NHX MCB's, which are no good with that bus bar.

Yes, it is 'NHX compatible'. Here it is:

http://www.screwfix.com/p/wylex-10-way-high-integrity-consumer-unit-with-9-mcbs-1-rcbo/83198

Seems like they packed it with the wrong busbars...

 

[EFLImpudence]

Sorry if repeating.

Isn't that why it's a 'flexible bus-bar'?

You can use it with off-set RCDs and Switches, as it is, or straight ones, by cutting off the crank.

Plus, as it's a HI CU you will need three pieces of bus-bar.

 

[AndyPRK]

No 'flexible bus-bar' means you can vary how many MCB's you want per RCD.


You could of course cut off the crank, but the label on the bus bar (meant for old MCB's) doesn't assist this.

 

[EFLImpudence]

No 'flexible bus-bar' means you can vary how many MCB's you want per RCD.

Is that set in stone and unchangeable?

Can it not mean 'has a variety of uses'.

 

[AndyPRK]

It's want they intend it to mean, long before NHX MCB's were created.

 

[confuzatron]

Isn't that why it's a 'flexible bus-bar'?

Well, the problem with this is that with the cranked pins sawn off these bars, there's no way to install this CU with a 5/4/1 split of the breakers that are included (1 RCBO, and 9 MCBs). If the idea is to chop off the cranked pins, then they need to enclose bars that are one pin longer. I'm installing a different configuration so will be able to get round this problem.

I'd also expect a note saying 'these bars wont work out of the box', but instead the instructions say to insert the cranked pin into the RCD/Switch live.

 

[PrenticeBoyofDerry]

Is the RCD fitted at the right end?
It looks to me if the busbar was to fit correctly and aligned with both RCD and MCBs that the RCD should be installed the other side of CU.

 

[EFLImpudence]

Isn't that why it's a 'flexible bus-bar'?

Well, the problem with this is that with the cranked pins sawn off these bars, there's no way to install this CU with a 5/4/1 split of the breakers that are included (1 RCBO, and 9 MCBs). If the idea is to chop off the cranked pins, then they need to enclose bars that are one pin longer. I'm installing a different configuration so will be able to get round this problem.

Yes, I appreciate that but, if the cranks are correct then, for an HI CU, you will need three.

Have you been supplied with three? If not, then it is wrong, anyway.

Do you not have a few pieces of busbar in your box?

I'd also expect a note saying 'these bars wont work out of the box', but instead the instructions say to insert the cranked pin into the RCD/Switch live.

If they don't work like that then something is wrong.

Perhaps in this case flexible just means you can bend it.