Older boards and availability/compatibility of devices

FWIW my take on this is that you can mix and match if the manufacturer of both the enclosure and existing devices, and the new device states that they are compatible.

e.g. Schneider making a statement with regard to their new breakers and their older Merlin Gerin range.


The issue lie outside BS 7671 it lie in the Electrical Equipment (Safety) Regulations, UK law and how the manufacturers comply with this regarding their consumer units and devices.


The manufacturers take the presumption of conformity route, bu designing, manufacturing and testing in accordance with the harmonised standards.

They do this for their range of devices and product that they foresee as being required to be utilised together.

This gives them a type tested assembly and offers compliance with the law.

So, anything that moves away from this manufacturers type tested assembly, either has to be declared as safe by them, e.g. the example above, or the person who modifies the assembly must ensure that it meets the requirements of the law.

They are placing a new assembly onto the market which is now no longer type tested and thus, must be verified as compliant with the requirements.


Now there is a British Standard that you can follow for the modification of distribution boards which is around £200 IIRC.

This covers device substitution in a type tested assembly as part of its remit, however, the standard states that following the guidance does not guarantee compliance with EN 61439, or any preceding standard.


The final issue that may be experienced as that as the unit is a type tested assembly, you would be looked on as the product supplier of this new, type tested assembly, and, may not have product liability insurance for the design, manufacture and supply of products into the market place.

Then you would have the technical file to compile and present to HSE, if there were an issue, and the devices/board OEM would not have to legally provide you with any information over and above that in the public domain.  Which would be inadequate to compile a technical file.

Manufacturers of things that must meet the European machinery directive are required to be able to create a technical file on demand, but don't need one initially.

http://www.hse.gov.uk/work-equipment-machinery/technical-file.htm


 As far as I am aware however, this does not apply to things where just the LVD applies, like switch gear- there a file must exist before CE marking and placing on the market.

However for a small product, a TCF need not be particularly arduous typically a few sides of A4, maybe less for a box with a switch in it.

• Description ( may be combined with a labelled sketch and the circuit diagrams)

• General Arrangement drawing (if complex enough to need one and a photo won't do.)

• List of standards that apply

• Records of any risk assessments and assessments to standards - may include the fact that some parts are already meeting some other standards, and have been tested by makers in similar containment structures. Now for something complex, this part may include loads of tests and a full fault tree exploring all failure modes,  but for a switch in a box, it is more of a looking at datasheet values and verifying safe operational area is not exceeded.

• Description of the logic for any controls with interlocks or relays. (if this occurs, then that happens.. Again, this can expand into a whole chapter if it is a controller for a chemical plant or something.)

• Datasheets for all critical sub-assemblies - especially those that are bought in as meeting other standards.

• Part list

• Copies of any markings and labels

• Copy of any instruction leaflet  or handbook  you create to go with it, (user, maintenance, installation)

• Test results, and descriptions of method of test if not obvious, and any QA commissioning procedures

Then the killer for the indemnity insurance is the signed  bit of paper saying I (name) hereby certify that (thing) described in this file meets the requirements of the relevant directives which are .. (list)


and then for the next decade you need to be able to produce that file again on demand.

Which almost never happens, which is good, as I am sure a great many things exist for which the TCF would not stand up to scrutiny.

Just a random thought ...


A new car is supplied with tyres which have been specified by the manufacturer. Some years later, those tyres may no longer be available 'cos technology has improved. Do you fit new tyres, or scrap the car? ?

Rather as is the case if you change the lamps in your car from filament to LED, the chaps that do the MOT will decide if the change is enough to invalidate the approval or make the machine unroadworthy.

It is more interesting for cars over 40 years old, as there is not only no approval, but no compulsion to have an MOT either.  Most vehicles of that era are also tax exempt as well.

It could make things quite fun if there was a similar exemption for 40 years old or older electrics.?

@roy bowdler "...However, coming from that perspective, should the principal be applied, that a suitably qualified and experienced person, exercising reasonable skill and care can make a decision?..."


I would hope the answer should be yes, but its more of how you document/prove that and perhaps the above comments show its not easy for the general electrician to do so, as they do not have access to a setup to do it.  Personally, I think a lot of devices could be (and perhaps are) interchangeable and there ought to be a [easier] mechanism to allow it for practicality, cost and reducing uneccessary waste.


Anyway,


Its been really interesting reading all the comments - thank you everyone !   Fortunately, I have secured confirmation from Volex of an approved device.  I am glad because outside of that most feasible solution, the others seemed prety unattractive all things considered.

Good to hear you found a workable solution.

It makes me wonder how we would get on now compared to when we used to just chuck a big component order to RS & Farnell and just assemble stuff straight out of the box/jiffy bag. We never used to bother with all of the paperwork nonsense mentioned in this thread. It either worked or it didn't. We learned by doing rather than endless analysis. That is not saying that we were just guessing in terms of product functionality, it just meant that if a panel was built, and component 'A' failed regularly, we'd go for component 'B' from a different manufacturer.

Right now, I have to make up a small panel to enable a cap start/cap-run single phase motor to run in both directions. This will entail buying a couple of contacters, and overload unit, an enclosure and some 6 x core cable plus glands.

Am I a manufacturer? Or am I a mere Assembler?