Re BS Standards for Distribution boards and Enclosures

Ian, perhaps you need (one or more) new bespoke boards?

In principle, you could perhaps replace the skeleton (for want of a better word) of the DB(s) with a modern one, which would be compatible with current outgoing devices. Then you would need a cover whose apertures match the new devices. That would not be too difficult to fabricate, but now you really are the manufacturer.

As Andy has mentioned half an hour ago, BS 60898 does not specify standard dimensions. I have to admit, I do not know where the standard 18 mm width is specified.

On the domestic side I have this dilemma at least once a week and it's probably a 50% chance that a suitable replacement device is available. The only way of really knowing if a device is compatible is by asking the manufacturer. many incompatibilities. For example the square D boards use two different size prongs, newer modules fit but don't make reliable contact in older boards.

Many manufacturers have chosen not to qualify newer modules in older boards.

Then we have companies that white label third part products and change suppliers over history whilst keeping the same brand name.

Overall it's a nightmare and takes fairly careful tracking of information that's quite often only provided verbally, easy to misinterpret or over interpret. Manufacturers don't have an incentive to help as they just want to sell new equipment.

At least if you have 40 identical boards it's only one exercise to investigate the options. Even possible to justify a face to face meeting with the manufacturer to look at options. 

Mixed manufacturers but even when the same, the operating handle is sometimes opposite in direction. An untidy board but those RCBO flying leads do little to assist! 
I wonder if there is any case where a contractor has been held to account for mixing devices or inadvertently taking on the role of the manufacturer. There are certainly scare tactics being employed, but I am not sure just how serious the consequences might be.

During my life as a contractor, I installed replacement pan assemblies into existing old enclosures of different manufacturers on many occasions. Usually done because of the logistical difficulty in replacing the enclosure, due for example to connections of old pyro cables or steel conduit. If the same situation arose now, I don’t think I would worry one jot about being the manufacturer, providing I was as confident as I could be that the arrangement was safe and, importantly, better than it was before.

an untidy board

But think of all the de-rating from  awkward grouping factors if it had been made up into a harness/loom assembly, surely a C2 safely side-stepped.

Sarcasm aside, the risk from mix and match in that situation is mainly that the bus prongs are short or in the wrong plane and a feeble contact goes un-noticed. To be fair I'd expect skilled hands to be able to spot that when selecting a compatible replacement . and if all the breakers were changed and the bus bar, then again if it all fits properly, then the real risk is low.

M

I have installed a bus bar extension to a new din rail device in the past. I have used a flexible wire to allow for this from the next device. This avoids having to fit a new device onto a mis-matched bus bar. I have never had any problems with this if I use a suitably sized wire. This is a quick fix when I need an instant solution. I normally fit the new device at the end of an existing bus bar.

Alf.

It might be a bit untidy, but who cares. You can't see the cables when the cover is on. As long as it is correctly wired and safe all is good. It ain't an art project. Plus over beautifying the wires costs more in time and labour.

Alf.