Electrical enclosure/case modification and liability?

[Ed DuffnerParticipant @edduffner79357]

Hi Everyone,

This is somewhat unrelated to model engineering so my apologies in advance. I wonder if I might ask for some advice from the electrical engineers/designers here or perhaps for some legal knowledge.

I converted a computer case a couple of years ago to accept a different kind of motherboard (but it could quite easily have been a custom modification or build for a CNC control box or similar).

Basically the existing steel rear panel secured with pop rivets was removed. A replacement with the new arrangement and cut-outs was made from aluminium and secured back onto the case using pop rivets, same as before. The rear panel is also the mounting point for the ATX power supply.

Since then several people have asked me if I could do the same modification for them. I've so far declined as I'm concerned that in the unlikely event of any kind of electric shock from the case I may be liable and as I am only a hobbyist and not a business I do not have public liability insurance.

I have received sheet metalwork training at BAe Bristol and was a qualified Electrician for 10 years working with enclosures and trunking systems.

If anything untoward did happen would this be a "is the new panel fit for purpose" kind of scenario?

– And relating back to this hobby, how would this affect hobby engineers making modifications to machine tools or control mechanisms for other people?

As always any advice offered is very much appreciated.

Thanks,
Ed.

[Ed DuffnerParticipant @edduffner79357]

Are there liabilities related to modifying control panels and computer cases?

[Martin KyteParticipant @martinkyte99762]

Hi ED.

Desktop computers have fully enclosed power supplies. Eassentially they are complete units in their own case. The external connections to the electronics are all below 50V so I would not worry about it.

Treat the computer as a box within a box. The mains bit is in the Power Supply Unit and you are only modifying the box that that fits into. You will usually find one or two earthing cables attached to the outer case but these are for screening and not safety earthing which is handled by the self contained Power Supply.

Hope that helps.

I work in an electronics workshop where we design and build gear for the rest of the Laboratory. We generally use enclosed power supplies in our equipment which deals with mains issues. As we don't sell anything we don't have to worry about CE compliance.

regards Martin

[Ed DuffnerParticipant @edduffner79357]

Wonderful, thanks very much Martin

I was thinking in terms of the 240V input to the primary side of the transformer and if that shorted to the chassis it could maybe cause a shock. But as you say it's self contained and the owner has a responsibility to protect the mains circuit with the correct circuit protection, in this instance the fuse in the plugtop.

Regards,
Ed.

[Johnboy25Participant @johnboy25]

Hi Ed…

I totally agree with Martin. The components your using will be CE marked so I don't believe there's a problem. One thing I will add is if your concerned about the case becoming live – check the continuity between the earth conductor of the three pin plug top to the chassis of your enclosure. You should see a very low resistance on the DMM and that's assuming the earth conductor is the same CSA of the live & neutral for fault current capability. Hope that make sense!

John

 

Edited By Johnboy25 on 11/02/2015 13:47:18

Edited By Johnboy25 on 11/02/2015 13:48:06

[BazyleParticipant @bazyle]

I suggest it is a bit like giving someone a lift in your car. Not a problem for helping a few mates to get to MEX and getting a few bob petrol money but if you start to make a business of it and 'plying for hire' then it is a whole new ball game.

[Peter G. ShawParticipant @peterg-shaw75338]

I'd like to describe a situation I found myself in some years ago, and what I did, or rather refused to do, to get out of it.

First, I am, or rather was, an apprentice trained telecomms technician, and as such can be expected to know something about electrics, but not necessarily the finer details of home wiring. Nevertheless, I have successfully, and safely, done electrical wiring and re-wiring in my own homes, including changing/fitting consumer units. This, of course, was pre Part P.

Behind our previous house there is a row of terrace houses and we, as you might expect became friendly with the lady in the house immediately behind us. She developed a problem and my wife asked me to have a look. The problem was that the television had stopped working. The tv was connected to a 5A round pin 3-pin plug which in turn was connected via an adaptor to a 15A socket on the skirting board which itself was about 4" high. The 15A socket was wired to one of two metal consumer units in a corner of the cellar. The consumer units were on adjacent walls and were connected together by means of an earth wire stretched across the corner. Permanent cabling appeared to be a mixture of TRF & Plastic. The cause of the problem was a blown fuse which I changed (rewired). On my way out, I noticed that the hall light switch had lost its cover plate leaving exposed terminals.

When, inevitably, the fuse failed again, I refused point blank to return saying that I considered the installation dangerous, and I wasn't going to risk getting involved with the authorities in case of electrocution or fire. Accordingly, the local electricity board people turned up, replaced the fuse (I presume) and put insulation tape of the exposed switch. Later the house was rewired.

My advice is to always err on the side of safety and self protection. Unless you are in the trade as it were, do not do anything like this for other people because if it goes wrong, then who is going to get the blame? By all means show people what you have done, but let them make their own modifications.

It may seem like a cop-out, but in today's climate where lawyer's are always looking for someone to sue, one cannot be too vigilant in protecting oneself against claims of negligence.

Regards,

Peter G. Shaw

[Ed DuffnerParticipant @edduffner79357]

Thanks John, I understand about the DMM, I should see virtually zero ohms.

Bazyle, I agree and if I were to ever get enough work to start my own business I'd jump at it. Being unemployed is soul destroying.

Ed.

[Ed DuffnerParticipant @edduffner79357]

Hi Peter, during my electrician years if ever I saw a multi way adaptor I would make it a point of telling the client they were potential fire hazards and should be binned immediately.

Going off topic, because it's my thread and I can, you're story reminded me of a house I wired for a lovely elderly couple who never had electricity. They were still using gas lamps on the walls, this was about 1990. When we fitted 60watt lamps as standard they said they were too bright, so we tried 40W but they settled for 25W.

Regards,
Ed.

[Russell EberhardtParticipant @russelleberhardt48058]

If you are purchasing the computer, modifying it, and selling it to someone you will have invalidated the CE certification and it would be your responsibility to get it re-tested and certified or to produce a technical file demonstrating compliance. This covers all relevant directives, not only safety but also EMC. That is clearly impractical and very expensive.

If, however, they purchase the equipment and instruct you to do agreed modifications you are only a subcontractor and any compliance issues rest with them.

Russell.

[David JuppParticipant @davidjupp51506]

Posted by Martin Kyte on 11/02/2015 09:52:54:

I work in an electronics workshop where we design and build gear for the rest of the Laboratory. We generally use enclosed power supplies in our equipment which deals with mains issues. As we don't sell anything we don't have to worry about CE compliance.

regards Martin

True for 'internal use' CE marking isn't required, but compliance with relevant directives is required.

[Martin KyteParticipant @martinkyte99762]

We do.

Martin

[Nicholas FarrParticipant @nicholasfarr14254]

Posted by Bazyle on 11/02/2015 13:48:31:

I suggest it is a bit like giving someone a lift in your car. Not a problem for helping a few mates to get to MEX and getting a few bob petrol money but if you start to make a business of it and 'plying for hire' then it is a whole new ball game.

Hi, no problem giving your mates or anyone else for that matter a lift in your car, but if you accept any payment, even to cover costs of the fuel you use, you may well infringe your insurance. Why so, because most peoples insurance has a clause excluding hire or reward and any payment whether it's private or business could be seen as hire or reward. If you are accepting money for giving lifts, it may be wise to consult you insurance company first. If you are hiring a car you need a licence to suit the type of hire you are giving.

Regards Nick.

[Neil WyattModerator @neilwyatt]

Went into this in great detail when I managed a charity.

It's perfectly OK to be refunded travel expenses up to the HMRC level of 45p a mile, whether its a private arrangement or you are doing it for an organisation as a volunteer. This is clearly accepted as not being for reward and my understanding is that it doesn't affect insurance, if it did millions of volunteers using their cars for charity work would be in deep trouble.

What is much murkier is working out when people driving minibuses need to have PSV licences…

Neil

[MuzzerParticipant @muzzer]

PCV!

[BazyleParticipant @bazyle]

Didn't the minibus thing change a few years ago as a result of EU interference. Us oldies can drive them on our licences but you kids can't which scuppered hundreds of potential volunteer drivers for charities etc. However the nail in the coffin was not that but needing to do s special CPC course (costing upwards of £2k) so you know how to change a wheel or some such trivia that people had managed without for all previous history of driving.

[Neil WyattModerator @neilwyatt]

Well they were PSVs in my day, youngster!

Neil

[Gordon WParticipant @gordonw]

I looked into the mini-bus questions years ago, and charging for petrol. Never really got an answer, the rules seem to change all the time. I think the base line is what your vehicle is registered as. Some people had tanks classed as private cars. If it all gets too much just try towing a trailer !

Edited By Gordon W on 12/02/2015 09:40:45

[Ian S CParticipant @iansc]

Got a friend who has a Daimler Ferrit Scout Car, registered as a Daimler Convertible(no turret version).

Ian S C

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by David Jupp on 11/02/2015 15:50:15:

True for 'internal use' CE marking isn't required, but compliance with relevant directives is required.

All of the Directives I have been involved with clearly state that they only apply to goods that are "placed on the market" in other words sold or hired out. If all equipment built and used internally had to comply it would prevent much research and development.

Russell.

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by Muzzer on 11/02/2015 18:03:38:

PCV!

Passenger Carrying Vehicle – what a ridiculous term. If you speak English you will know that that must include cars and even horse dawn carts!

Russell.

[David JuppParticipant @davidjupp51506]

Posted by Russell Eberhardt on 12/02/2015 10:22:53:

Posted by David Jupp on 11/02/2015 15:50:15:

True for 'internal use' CE marking isn't required, but compliance with relevant directives is required.

All of the Directives I have been involved with clearly state that they only apply to goods that are "placed on the market" in other words sold or hired out. If all equipment built and used internally had to comply it would prevent much research and development.

Russell.

Russell – if you read the UK guidance notes on the low voltage directive (the most obvious one applying here, but not the only one), you will see where my comments originate. (middle of page 17 of this document **LINK** )

Surely any company would want in house built equipment to be safe (taking into consideration the level of knowledge, expertise, training of those that will use it).

[MuzzerParticipant @muzzer]

Point being that you need a proper bus driving licence (and a tacho) to drive a bus, whether or not you are charging for the ride. Previously you could drive a full sized bus ("heavy car&quot on a normal licence as long as you weren't charging the passengers, eg for a works bus or football team. That was ridiculous of course, so it's a good thing they changed the law. It covers anything from a midibus (>3.5t) to a large coach, urban bus or double decker.

To me, the most challenging part of the test is the reverse parking which requires you to position the rear wheels of a vehicle (typically a 13m coach) within a 1m long box. Sounds easy but believe me it isn't. And if you fail that, you fail the test. I passed mine in Norwich around 1990, having learnt to drive coaches around Cambridge city centre and Norfolk. Didn't squash any cyclists but it was an interesting challenge and taught me some useful driving perspectives!

Murray

[Anonymous]

Posted by Muzzer on 12/02/2015 11:02:57:

Point being that you need a proper bus driving licence (and a tacho) to drive a bus, whether or not you are charging for the ride. Previously you could drive a full sized bus ("heavy car" on a normal licence as long as you weren't charging the passengers, eg for a works bus or football team. That was ridiculous of course, so it's a good thing they changed the law. It covers anything from a midibus (>3.5t) to a large coach, urban bus or double decker.

To me, the most challenging part of the test is the reverse parking which requires you to position the rear wheels of a vehicle (typically a 13m coach) within a 1m long box. Sounds easy but believe me it isn't. And if you fail that, you fail the test. I passed mine in Norwich around 1990, having learnt to drive coaches around Cambridge city centre and Norfolk. Didn't squash any cyclists but it was an interesting challenge and taught me some useful driving perspectives!

Murray

Ah yes, I have a recollection of driving an electric bus chassis around the WD carpark under your supervision. I don't remember hitting anything?

Andrew

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by David Jupp on 12/02/2015 11:01:17:

Russell – if you read the UK guidance notes on the low voltage directive (the most obvious one applying here, but not the only one), you will see where my comments originate. (middle of page 17 of this document **LINK** )

Surely any company would want in house built equipment to be safe (taking into consideration the level of knowledge, expertise, training of those that will use it).

Yes, I can see where your comments originate but that document is only a guidance document having no legal weight. The LV Directive ( amongst others) clearly states that it applies to equipment "placed on the market" and nowhere does it state that it applies to any other equipment. This is because the intention of these directives is to enable free trade of products across the EU. They are not concerned with anything that is not sold or hired out.

Of course you want in house equipment to be safe and fortunately that is cheap and easy to verify however compliance with the standards that demonstrate compliance with the EMC Directive is difficult and expensive to test (I know, having been involved in the writing of some of the standards).

Russell

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