I am working with a company who are designing air sampling equipment - basically a fan in a box which is designed to collect air samples and with results inspected every 6 hours. The equipment is 24vDC but powered by a 240vAC generator which supplies via a secondary back-up battery pack and transformer. The generator and battery pack are earthed/grounded via an earth spike attached to the generator. My question is does the 24v sampling pack require grounding too? It's been suggested that BS EN 60204-1 Safety of machinery. Electrical equipment of machines. General requirements might apply but from my non-electrical background I am less convinced.
ANY advice will be gratefully received.

In fairness, where the equipment will be installed there will be no access to any main supply which could be stepped down, plus the users have a whole load of 240v generators that they've mandated to negate the need to pay for around 100 replacement lower voltage ones. I'm afraid that the design is what it is with pre-prodcution work well advanced and 3 prototypes produced. So other than a few tweeks here and there that can't be changed - which brings me to the "safety" element. This is a classic case of instead of design to be safe (although at least they defined 24v) I am now left with "now it's designed and being built confirm that it is safe to use." Exactly the oposite of what shouild happen and by a company who promote a "design for safety" message. At the moment the equipment itself is not earthed because they've considerred it to be 24v - my lack of knowledge makes me wondeer about the connections to what starts as a 240v supply.

Hello Alan,

OK, it is impossible to do this retrospectively by the H&S department.
To comply with the LVD & CE mark the equipment, which is BTW a Statute Law requirement, this has to be designed in and built in from scratch.
You can get a specialist in to assess the product and come up with a deficiencies list, but this is a very poor way of doing this.
However, your location is listed as Bristol area, so not that far away should you require this.

Next, 240V ac is an acceptable primary supply.
However, this supply must be suitably connected, compliance with EAWR & PUWER are absolute.
This will also need to comply with BS7671 & if temporary then perhaps BS7909, and even depending on the location, BS7375.

Now, as far as earthing of the 24V dc side, this requirement depends on the origin of the supply.
If the equipment has been designed & manufactured in accordance with 60204, then this requirement will be obvious and your designers if competent will have implemented this.

It worries me a lot that as an H&S person you are looking into stuff that your designers should have taken care of before the product even “left the drawing board”.

There is no single simple answer to the earth or not to earth predicament, it depends.
Much more information is required.

Next, just because the users have something, does not make it necessarily suitable.

“YOU” are the designers of the product, “YOU” must design it to be inherently safe & compliant.
“YOU” must design out the risks and hazards, any residual hazards and risks MUST be detailed in the equipment documentation giving safe usage instructions to minimise these hazards & risks, and “you” must be happy that “you” have done everything in “your” ability to mitigate as much of the risk & the hazards that are economically viable.
Remember, the “cost” of your product killing someone is not something to be sniffed at.

Now, the designers MUST have done their design DRA’s so they must have all of the required information to develop this, so they are simply passing the buck to you, for work that they should have already done, if they haven’t, then you can’t compile the TF, thus, you can’t sell the product legally.

I really think that this requires further competent input with the information that has been presented in this thread.

Waste management, if this is the area of application is quite a unique environment, which I do have experience of.

Oh, and you can’t use a transformer to do anything useful with the supply from a battery of any sort.

I can say no more than please PM me, else I will fall foul of the forum rules on advertising I suspect.

Well, I have to say that a totally un-earthed secondary is very unusual, & I would love to know how it complies with 60204, if that is what you are suggesting.

I would be interested in knowing how the 24V equipment complies with clause 6.4.1 b), and, I trust that the source of supply & supply system design, meets the requirements of 6.4.1, 6.4.2, & 8.2.5 of 6.204 & associated requirements.

My specialism is also machinery, control systems, 60204, 60261, 7671, 13849, etc. etc., hence for example, you don't find me giving advice on excavations or skin issues for example.

Your reply is typical of the issues faced by respondents on here, we only get part of the story, thus, all replies are tainted with only part of the information we need to reply correctly.
If you want, or need an accurate reply, then you need to provide accurate and adequate information.

I find it hard to understand why the equipment designers are not competent to undertake the whole design and specification without external input.
They MUST be competent to address ANY & ALL H&S issues else they are not competent to design the product.