Consumer unit.

[PrenticeBoyofDerry]

I don't think it is a matter of warranty John, the reason for type testing is safety!

So, putting aside for a moment the very real issue of bus-bar alignment compatibility, if you have say, a Hager CU, and you put a Siemens MCB in it, what safety risks are there?

Feel free to get real.

I am sure if you contact the manufacturers and ASTA they will be able to inform you better than I, The manufacturers generally specify that their boards have been tested to certain standards as are the components within them and for safety reasons they recommend these are the products that should be installed within them. They do not recommended other makes/brands of components to be used, as they have not been specifically tested for their boards, I would not expect manufacturers to go testing all other manufacturers products to assure they do meet their requirements, you mAy say they are looking after their own financial interests but surely it would be up to the manufacturers of the internal components to prove reliability and safety, to install these in foreign boards not visa a versa. In my opinion installing mixed breakers is a no no, so I don't. That does not say that they cannot be mixed providing, as I have stated they are type tested for the board and the meet the EN/BS specification for the board, so if Siemens devices have been type tested and meet spec for a Hager board they would be no safety issues, if they have not there is a potential that there could be.
I would not fit a set of brakes to my car, that were not designed or met the specification of it!

 

[ban-all-sheds]

I am sure if you contact the manufacturers and ASTA they will be able to inform you better than I,

No - they will just give me a different pile of waffle.

The manufacturers generally specify that their boards have been tested to certain standards as are the components within them and for safety reasons they recommend these are the products that should be installed within them.

Of course they do. But....

They do not recommended other makes/brands of components to be used, as they have not been specifically tested for their boards,

That is true. But....

I would not expect manufacturers to go testing all other manufacturers products to assure they do meet their requirements,

Nor I. But please try to exercise common sense and reality over what those "requirements" can really be.

you mAy say they are looking after their own financial interests but surely it would be up to the manufacturers of the internal components to prove reliability and safety, to install these in foreign boards not visa a versa.

And here's the "But...":

The breakers all conform to the same standards for performance. Within different makes of similar standing they are all going to be of similar quality and safety and reliability.

Using all your skill and judgement, please explain, to the best of your knowledge and belief, what problems there could be with putting Breaker A in "foreign" enclosure "B" (apart from, as previously said, issues of busbar alignment).

If you have an enclosure, with a DIN standard rail, please tell us what problems you think there could possibly be if breakers from two makers were clamped onto that rail.

If I were panel building, would every maker of devices insist that I had to buy every device and enclosure I needed from him? Or would it be OK for me to buy an enclosure from Sarel, breakers from Hager, contactors from Telemecanique, and distribution blocks from Aico?

In my opinion installing mixed breakers is a no no, so I don't.

By what is that opinion informed?

That does not say that they cannot be mixed providing, as I have stated they are type tested for the board

What does that mean? What does "type testing" consist of?

and the meet the EN/BS specification for the board,

What are those specifications? Apart from the ones for the profile of the rail, the distance between it and the front panel, and the aperture in that panel, what other relevant ones are there for "the board"?

so if Siemens devices have been type tested and meet spec for a Hager board they would be no safety issues, if they have not there is a potential that there could be.

The potential for what safety issues? Can you suggest any reasonably likely ones? Any possible ones? Even any ridiculously unlikely ones?

No maker is going to test or approve the use of other makes of breaker in his CU, if only for the reason of busbar alignments, but it's perfectly fair for him to say "why should I?" for commercial reasons. And the lack of type testing does have a real consequence as without it you lose the exemption from having breakers rated for your PFC.

But safety?

I would not fit a set of brakes to my car, that were not designed or met the specification of it!

I hope you aren't daft enough to think that that is a good analogy, or to think that others would.

 

[JohnW2]

...so if Siemens devices have been type tested and meet spec for a Hager board they would be no safety issues ...

As BAS has asked, what does that actually mean?

You can't really be criticised, since you are merely quoting 'official chapter and verse' - but what BAS and I are asking you is whether you really believe that there is any significant 'safety issue' in mixing components within a CU, provided that they are mechanically (dimensions etc.) compatible.

Do I take it that you have seen (or heard of) problems that have arisen from a CU containing (mechanical/dimension-compatible) mixed-make components?

Kind Regards, John

 

[AndyPRK]

Don't forget bell transformers don't actually connect to the bus bar. They only sit on the din rail. That is as exciting as they get!

 

[JohnW2]

Don't forget bell transformers don't actually connect to the bus bar. They only sit on the din rail. That is as exciting as they get!

Quite so - the short length of ELV cable within an enclosure which also contains LV cables is the only thing for people to worry about - an issue which, I suppose, also arises within the enclosure of any LV->ELV power supply.

Kind Regards, John

 

[sparkwright]

I often see bell transformers in CUs, with T+E on the secondary side to a surface lightswitch outside the CU, and then bell wire from there to the bell. Gets around the segregation issue, but kopex is a much neater solution.

Surely though, having a surface light switch present defeats the whole object ih having a cu bell transformer. A cu bell transformer is generally to prevent all that clutter around the cu to make it look nice. Where possible, I would do the bell transformer on it's own MCB, so it can be isolated easy if there is a fault - without effecting other circuits.

The light switch you mention won't isolate the transformer, which is partially useless.

On the rare occasions I have used a cu bell transformer, I have sleeved the bell wire in the cu.

Not very satisfactory I grant you, but looked good.

 

[JohnW2]

Surely though, having a surface light switch present defeats the whole object ih having a cu bell transformer. ...

Quite. If one must have a bell transformer in a CU (seems like a 'waste of CU space' to me!), one of the other solutions (sleeving of ELV cable within CU, or use of 0.75mm² 2-core flex 'all the way') would seem more sensible than adding unnecessary external accessories.

Kind Regards, John

 

[stillp]

...so if Siemens devices have been type tested and meet spec for a Hager board they would be no safety issues ...

As BAS has asked, what does that actually mean?

You can't really be criticised, since you are merely quoting 'official chapter and verse' - but what BAS and I are asking you is whether you really believe that there is any significant 'safety issue' in mixing components within a CU, provided that they are mechanically (dimensions etc.) compatible.

Do I take it that you have seen (or heard of) problems that have arisen from a CU containing (mechanical/dimension-compatible) mixed-make components?

Kind Regards, John

A report was produced by a major manufacturer some years ago in which they assessed the performance of their CU fitted with MCBs and RCBOs that were claimed to be 'compatible', or in some cases no claim was made, but the components were clearly copies of the major manufacturer's products. Two main problems were found. One was incorrect tolerances on the busbar clamps, the implication being that the original product that was copied was towards one extreme of the manufacturing tolerances. This caused increased heating within the CU. The other problem was with the EMC of the RCBOs when a mixture of original and 'compatible' products was installed. I think this was because the internal components were arranged differently, e.g. the electronics on the original was on one side, the current-carrying parts on the other, but the copy was a mirror image, so the electronics of the copy was not shielded in the way that the original was. The effects included both spurious tripping and failure to trip within the correct characteristic. From memory, I think that both the original and copy products were affected.
The copies also had a much higher watts loss than the originals, so the inside of the CU was hotter than expected, which could affect calibration.
What couldn't be quantified was how much of the unwanted effects were due to the mix of products, and how much was just the poor manufacturing quality of the copies.

Sorry I can't remember any more detail (at least any that I can post on a forum) as this was an internal presentation some years ago, and I had no responsibility for those products so didn't take too much notice. The report was of course confidential so I didn't get a copy.

 

[kai]

I have noticed that a lot of people put a switchfuse in the tails before the consumer board to get round the high PFC problems - Wylex have just brought out a new range of stylish all metal cased 60/10/100 Amp switchfuses with Dual Screw Terminals just with this in mind!!

 

[JohnW2]

A report was produced by a major manufacturer some years ago in which they assessed the performance of their CU fitted with MCBs and RCBOs that were claimed to be 'compatible', or in some cases no claim was made, but the components were clearly copies of the major manufacturer's products.

Interesting. That's obvioulsy a bit different from what I was talking about. I was not talking about 'copies' or 'compatibles; but, rather, about full-spec legitimate branded devices of other manufacture. As you go on to say 'copies' and 'compatibles' opens up the possibility that some of the comparative results may have resulted from non-ideal design and/or manufacture - whereas I was talking about 'full-spec' products from reputable (but 'other') manufacturers.

Two main problems were found. One was incorrect tolerances on the busbar clamps, the implication being that the original product that was copied was towards one extreme of the manufacturing tolerances. This caused increased heating within the CU. ....

Indeed - both BAS and myself have acknowledged the issue of bus-bar comparability. I must say, however, that I'm surprised to hear that tolerances of the clamps had an appreciable impact on the quality of the electrical connections - IF the busbar fits satisfactorily (dimensionally) and the clamp can be tightened satisfactorily, I would not have expected 'connection problems'.

The other problem was with the EMC of the RCBOs when a mixture of original and 'compatible' products was installed. I think this was because the internal components were arranged differently, e.g. the electronics on the original was on one side, the current-carrying parts on the other, but the copy was a mirror image, so the electronics of the copy was not shielded in the way that the original was.

Fair enough, but that's rather 'esoteric' and I don't think really qualifies as one of the alleged 'safety issues' (of mixing devices), does it?

Do you recall whether, other than the busbar clamp business, they identified anything else which could reasonably be regarded as a 'safety issue'?

Kind Regards, John

 

[JohnW2]

I have noticed that a lot of people put a switchfuse in the tails before the consumer board to get round the high PFC problems - Wylex have just brought out a new range of stylish all metal cased 60/10/100 Amp switchfuses with Dual Screw Terminals just with this in mind!!

As recently discussed, have you actually come across, or heard of, any domestic installations which actually suffer from these "high PFC problems" (except conceivably in London)?

Kind Regards, John

 

[stillp]

A report was produced by a major manufacturer some years ago in which they assessed the performance of their CU fitted with MCBs and RCBOs that were claimed to be 'compatible', or in some cases no claim was made, but the components were clearly copies of the major manufacturer's products.

Interesting. That's obvioulsy a bit different from what I was talking about. I was not talking about 'copies' or 'compatibles; but, rather, about full-spec legitimate branded devices of other manufacture. As you go on to say 'copies' and 'compatibles' opens up the possibility that some of the comparative results may have resulted from non-ideal design and/or manufacture - whereas I was talking about 'full-spec' products from reputable (but 'other') manufacturers.

Different people have different concepts of 'reputable' John. Are the MCBs from let's say Hager, Siemens, and Schneider physically interchangeable?

Two main problems were found. One was incorrect tolerances on the busbar clamps, the implication being that the original product that was copied was towards one extreme of the manufacturing tolerances. This caused increased heating within the CU. ....

Indeed - both BAS and myself have acknowledged the issue of bus-bar comparability. I must say, however, that I'm surprised to hear that tolerances of the clamps had an appreciable impact on the quality of the electrical connections - IF the busbar fits satisfactorily (dimensionally) and the clamp can be tightened satisfactorily, I would not have expected 'connection problems'.
[/QUOTE]AFAICR, there were problems.

The other problem was with the EMC of the RCBOs when a mixture of original and 'compatible' products was installed. I think this was because the internal components were arranged differently, e.g. the electronics on the original was on one side, the current-carrying parts on the other, but the copy was a mirror image, so the electronics of the copy was not shielded in the way that the original was.

Fair enough, but that's rather 'esoteric' and I don't think really qualifies as one of the alleged 'safety issues' (of mixing devices), does it?

[/QUOTE]Yes, it was a safety issue. It affected the tripping curve of the RCBOs.

 

[JohnW2]

Are the MCBs from let's say Hager, Siemens, and Schneider physically interchangeable?

If they are not physically interchangeable (dimensionally), then they are not interchangeable, and that's the end of the story. That has been acknowledged.

Yes, it was a safety issue. It affected the tripping curve of the RCBOs.

Oh, I see, I didn't realise that's what you meant by 'problems of EMC'. I have to say that I would not be particularly happy to be reliant on RCBOs whose tripping curves were that sensitive to external influences - which, let's face it, could theoretically come from sources outside of the CU!

Kind Regards, John

 

[stillp]

I would not be particularly happy to be reliant on RCBOs whose tripping curves were that sensitive to external influences - which, let's face it, could theoretically come from sources outside of the CU!

There are a lot of magnetic fields inside a CU! Remember that a manufacturer's type-tested CU will (should) have been tested in a way that would discover any interaction between the devices within that CU.

 

[stillp]

If I were panel building, would every maker of devices insist that I had to buy every device and enclosure I needed from him? Or would it be OK for me to buy an enclosure from Sarel, breakers from Hager, contactors from Telemecanique, and distribution blocks from Aico?

I'm sure that would be OK BAS, since you'd be testing that panel after construction, wouldn't you? However, if you then decided to change the contactors (and of course their associated overloads) to Rockwell, you would have changed the design, and would therefore need to re-test.