230V control circuit

further, this Germanic interpretation on who can CE mark what, and when they should do so is particularly clear.
https://www.gt-engineering.it/en/insights/machinery-directive/datoredilavoro-marcatura-ce/

I'm less sure this happens in practice.
Mike.

Hi Graham,

Thanks for your comments on this, it's very helpful.

There is still confusion in our camp where Clause 9.1.1 says, "Where control circuits are supplied from an AC source, transformers having separate windings shall be used to separate the power supply from the control supply". This doesn't specify to what voltage the control voltage should be, but what would be the point of adding a transformer to go from a 230V supply to 230V (the maximum under Clause 9.1.2) control?? 

Essentially, I'm still being told on one hand that the supply should (although not in law) be stepped down...(to 24V).

Chemenger said:

This doesn't specify to what voltage the control voltage should be, but what would be the point of adding a transformer to go from a 230V supply to 230V (the maximum under Clause 9.1.2) control?? 

This is questioning the provisions of the standard ... and I can only provide an opinion not an 'interpretation'.

This is so that electrical faults in the power circuit isn't present on the control circuit, for safety. It also permits segregation for fault-finding.

And perhaps also a safety concern, a transformer, even a 1:1 ratio unit, ensures a far lower PSSC on the control side of things, as presumably the transformer will be a low wattage unit, only just large enough to operate the contactor primary coils and any indicators with a modest safety margin,
If there are no contactors and the switches are in series with the load itself, like a DOL starter, that part of the wiring  is not a control circuit, but a power one.
Mike

Chemenger said:

But the panel has 2 start/stop buttons for pump motors, an activation switch for a temperature controller, and an overtemperature interlock. Doesn't this preclude that exception? 

The problem is that you are asking for an interpretation of the standard in the particular circumstances. Only a Court of Law can interpret a standard.

Engineers can only provide a professional opinion - and even then, would need full facts, not just a discussion in a Forum.

The question you ask, suggests that either yourself, and/or a colleague, have interpreted a standard in a particular way (although in a different way to the interpretation provided at the start of this thread which mentioned effectively ELV at 24 V), whereas in fact the manufacturer has interpreted it in another way.

Yes, these differences need to be sorted out ... but without speaking with the manufacturer and engaging in dialogue, the only way to move this on is to involve legal professionals, because even if you were to get someone in this forum to agree with you, the manufacturer (who actually makes the legal declaration) appears to have a different view and they may well stand by that.]

To consider one possible outcome ... if you and the manufacturer don't agree, and the manufacturer refuses to make any changes, yourcompany decides they will make the changes (to avoid legal action or returning the product etc.) ... which makes your company responsible for the safety of the Machinery (in its entirety perhaps) going forward ... which in itself would not be sensible without taking legal advice ... and the legal advice might be to sort it out properly with the manufacturer at this stage ?