Electrical product advice needed

Hi All,

I need some guidance on electrical safety of products rules. I have made a lighting base for a glass sculpture. It is a sealed LED driver and a 20W LED chip on a heatsink. There is a fuse in the mains side and the mains cable and switch are purchased prebuilt. The cable is with an earth wire and the driver is earthed to a common point on the terminal block, which is connected to an aluminium base plate. I cut the base plate on CNC and there are plenty of ventilation holes, but strategically placed so that it is difficult to reach a mains voltage through them. The sculpture base is either bronze or cast iron and it has the base plate bolted to it. I will have the finished units PAT tested, but I am wondering if there is any other official process I have to go through before they are offered to the public.

The pictures attached gives you an idea of the bases, but one pic was of a failure of the resin embedding of the glass, so doesn't show the base underneath. The second one was a brief test of the lamp.

Attachment 19117Attachment 19118

Cheers,
Rob

If you can poke any household item through a vent hole and get at mains your product liability insurance might not pay out in the event of a child poking a straightened paperclip through a hole.
Most current products use strategically placed mylar or other physical shielding to make access to mains impossible without making a real effort to cause damage,

- Nick

Ta Nick,

I will put a 3D printed box round the terminal block. I take your point about product liability insurance.

Rob

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Originally Posted by cropwell

Hi All,

I need some guidance on electrical safety of products rules. I have made a lighting base for a glass sculpture. It is a sealed LED driver and a 20W LED chip on a heatsink. There is a fuse in the mains side and the mains cable and switch are purchased prebuilt. The cable is with an earth wire and the driver is earthed to a common point on the terminal block, which is connected to an aluminium base plate. I cut the base plate on CNC and there are plenty of ventilation holes, but strategically placed so that it is difficult to reach a mains voltage through them. The sculpture base is either bronze or cast iron and it has the base plate bolted to it. I will have the finished units PAT tested, but I am wondering if there is any other official process I have to go through before they are offered to the public.

The pictures attached gives you an idea of the bases, but one pic was of a failure of the resin embedding of the glass, so doesn't show the base underneath. The second one was a brief test of the lamp.

Attachment 19117Attachment 19118

Cheers,
Rob

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The answer is yes. If it can be plugged into mains and not fed through a commercially available power supply with low voltage then you should not continue with this idea, unless you can certify the product and know what you are doing, which you obviously don't. Even at low voltage there is a risk for causing fire if the used material is wrong, or you make a design error, so even if it is fed with an approved PSU you can still be liable. The regulations concerning electricity are not just some rules and regulations, but law, so breaking those are pretty serious. If your product can't, or won't be certified to follow the regulations then you are not allowed to sell, and if you do then you are taking huge risks. All those rules and regulations can't be explained in a few words on an Internet forum.

Now, it is no secret that I am not a UK resident, but I am pretty sure your regulations are just as stringent as ours here in Sweden.

Good luck.

It's covered in this -

https://www.gov.uk/guidance/electric...sponsibilities

You'll need to read the attachments too for the relevant information, I don't assume that smart people can't read and learn things they don't already know! ;-)

I'd look at incorporating a thermal fuse into the power feed such that excess temperature (you'll have to research and determine that) will cause power cutoff, also consider crimped tubular terminations for the mains wires at the connector block.

Regards,
Nick

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Originally Posted by magicniner

I'd look at incorporating a thermal fuse into the power feed such that excess temperature (you'll have to research and determine that) will cause power cutoff, also consider crimped tubular terminations for the mains wires at the connector block.

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Thanks Nick, I will look through the site and see what is relevant to my glassblower friend.

At the moment, he produces an item http://www.stuartakroydglass.com/new...s/?galAlbum=44 which is a glass sculpture in a solid steel base. His idea was to light it from below with a fairly powerful LED chip. We are at a very early stage in development, with one working prototype. It has to be soak tested to see how the temperature rises on the LED, and to see if the driver is suitable etc.
We hope to get some to show at a Craft Fair in London in 4 weeks time. This will be to gauge interest in the idea. If it flops - well - so be it. If it shines out then we will go further.

Nick - thanks for your sensible input, when I have made a few more bases, I will post some pictures of the innards.

Cheers,

Rob

Rob Have you thought about a 12V or 24V led and feed it from a commercial power brick CE aproved

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Originally Posted by Clive S

Rob Have you thought about a 12V or 24V led and feed it from a commercial power brick CE aproved

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Yes, but couldn't find a suitable one. The driver we are using on out test rig is this one http://www.ebay.co.uk/itm/2015292070...%3AMEBIDX%3AIT and it has CE marking and IP65 printed on it (???).

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Originally Posted by cropwell

Yes, but couldn't find a suitable one. The driver we are using on out test rig is this one http://www.ebay.co.uk/itm/2015292070...%3AMEBIDX%3AIT and it has CE marking and IP65 printed on it (???).

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Can you buy one that is CE rated?

This might be a good read: http://www.meanwell.eu/ExclusivePDF/...OVALS-NOTE.pdf

Rob,
I didn't make it clear but my reasoning for the thermal fuse is to use one rated above the temperature which the light unit might reach in a very warm room under normal operating conditions such that the power would cut before anything got hot enough to melt or burn,
Regards,
Nick

1. Thanks Clive, A right riveting read :fatigue: Actually it may be relevant as the LED driver pictured on page 1 is the one (or very similar) we are using. I realise that CE could mean 'Chinese Equivalent'.

2. Yes Nick, I realised that. We still have tests to do to see temperature rises, but the LED is on a heatsink with plenty of free air (a fan would detract from the artistic aspects). As far as melting is concerned, I have no worries over the cast iron or bronze, but start to get a bit wary about the aluminium. My main concern is the driver and LED chip going pop in flames. There is a 20mm fuse holder which will be furnished with a 1A glass fuse.

No I am not being sarky! I am just knackered after a hard day watching my son do some grafting. I have just had to resort to painkillers (Bacardi and coke). Thanks mates, for taking onboard this issue and providing me with some meat to chew.

Cheers,

Rob

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Originally Posted by cropwell

My main concern is the driver and LED chip going pop in flames..

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Yes, that's the bit that will get hotter than normal before it burns ;-)

Here's some pics of the lamp base. Don't forget that is only a prototype to test the idea out, nowhere near a finished product, so if you see anything that needs to be changed, please say.

My desk isn't normally like that, I tidied it up to get some space to take the photos :applause:

Attachment 19138Attachment 19139Attachment 19140Attachment 19141

Having looked through the photos, I can see one thing that needs attention - the mains wires input to the driver !

Cheers,

Rob

Rob I am not an expert But I would put some mica or other suitable material under the mains choc block so as to make sure no strands of wire will touch the ali base.

edit I don't see the frustation hammer on the table

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Originally Posted by Clive S

I would put some mica or other suitable material under the mains choc block so as to make sure no strands of wire will touch the ali base.

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You are right, the mains shrouding will have to be attended to. All things electrical have to be quadruple safe, just to protect yourself from twats. I hope the sculpture itself will be expensive enough for owners to keep brats with paper clips off it. But you k-never k-know. If people are daft enough to try and dry off a poodle in a microwave and then successfully sue because the manufacturers instructions didn't say not to, what hope is there for the intelligent world ?

TTFN

Rob

Quote:

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Originally Posted by cropwell

Here's some pics of the lamp base. Don't forget that is only a prototype to test the idea out, nowhere near a finished product, so if you see anything that needs to be changed, please say.

My desk isn't normally like that, I tidied it up to get some space to take the photos :applause:

Attachment 19138Attachment 19139Attachment 19140Attachment 19141

Having looked through the photos, I can see one thing that needs attention - the mains wires input to the driver !

Cheers,

Rob

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Why don't you show this to a local, CERTIFIED electrician and ask his/her opinion? It may cost £100-150 if you want a written report also, but can't be that expensive if you only wants an opinion. Anyway, it is money well worth spending if you have this as a serious business idea.

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Originally Posted by A_Camera

Why don't you show this to a local, CERTIFIED electrician and ask his/her opinion? It may cost £100-150 if you want a written report also, but can't be that expensive if you only wants an opinion. Anyway, it is money well worth spending if you have this as a serious business idea.

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Most Part P sparkies are not only CERTIFIED but CERTIFIABLE. To get any valuable advice or opinion, I would have to go to the IEEE to find a suitable Electrical Engineer. The most sensible testing, at this stage, is PAT*, coupled with common safety sense. We know from experience in this forum, that errord are easily made, and often missed in review. It is like having a document proof read, you probably won't spot your own mistakes, but someone else sees them immediately because they go in with a different mindset.

If the idea of an underneath lit glass sculpture has any artistic appeal and serious commercial possibility, then we will go the whole hog with a CE driver and integral switched mains cable and a plug suitable for the destination country, and go for the IEEE cert, but that costs mega bucks.

Cheers,

Rob




* which we need to have done anyway, as the exhibitions won't accept anything plugged in, without a green sticker.

++ did you spot it ?

Post removed.

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The reason I am saying it is that I can see several very basic mistakes in your design, which are pretty simple to to fix, but are very important from the safety perspective. I think that what you may regard "common safety sense" is not the same as what a qualified person would, and it is always a good idea to ask for their opinion.

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If you can see them would it not be nice if you stated what they are as that would be more helpful.

Let me give you an idea of what we are doing.

Stuart Akroyd http://www.stuartakroydglass.com/ is a good friend who asked me to develop an idea for lighting a sculpture piece he does. For the moment, we are making about 6 for show at an exhibition and the piece will be offered for sale if enough interest is shown, when the electrics are fully done and tested.

It will be a limited edition, so no production run of 1,000's and no big budget for production testing. We will be switching on and leaving it on until we get to a steady state temperature and we will be testing it in a kiln to see how it copes with ambient temperatures up to 60deg C. We are currently testing a piece to see if the resin that embeds the glass into the base deteriorates or softens at temperature and currently we are at 70deg C with no problem.

Just to put perspective on things.

Rob

I removed my post.

Yes, I take on board these comments. First of all the cover was 3D printed to give a pattern for casting in bronze, which the one in the photo is. Secondly the fuse/connector block fixing screw acts as an earth point as the earth wire from the driver cable is connected to it. In fact, the earth wire connected to the driver fixing is redundant. The driver itself is two-wire and thus I presume, double insulated. Finally, the cable is a prewired one with one end stripped and crimped and a moulded on plug and switch, which I did not want to remake, but I understand your concern.

Hi,
We have done some testing on the unit now and it is not good. The driver gets too hot. The steady state temperature is reached after 45 minutes and is 50 deg C on the top of the casting above the driver. The baseplate is too hot to touch. Even if the unit remains electrically stable, at that temperature it would damage the furniture it is on. The two units we have tested give similar results.

Clive - your suggestion of a wall wart or separate power supply like this one http://www.ultraleds.co.uk/white-60w...ed-driver.html is looking the most sensible way forward and I will be talking to ultraleds on Monday.

Cheers

R

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Originally Posted by A_Camera

certified

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A certified UK Electrician was surprised to find an IP56 RCD socket under my kitchen sink, he said "We just fit ordinary sockets under sinks"

Certified Electricians here are not taught to think logically or apply reason or spot issues not covered specifically in their training or manuals, if you happen to find one who is particularly intelligent that's great but is is not a requirement for certification ;-)

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Originally Posted by magicniner

Certified Electricians here are not taught to think logically or apply reason or spot issues not covered specifically in their training or manuals, if you happen to find one who is particularly intelligent that's great but is is not a requirement for certification ;-)

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I think that Part P (domestic) Certification covers two topics 1. Not burning the house down and 2. Not electrocuting anybody.

Generally there is a two day course and a 20 question exam (with course books allowed).

It is about on the level of - Do No Harm and don't drag your knuckles when you walk.

R

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A certified UK Electrician was surprised to find an IP56 RCD socket under my kitchen sink, he said "We just fit ordinary sockets under sinks"

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I think that modern wiring dictates that you have to have the kitchen on a separate ring with RCD (could be wrong though)

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Originally Posted by Clive S

I think that modern wiring dictates that you have to have the kitchen on a separate ring with RCD (could be wrong though)

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Yes, Clive, I am sure you are right for new build or major rewiring. When I had my kitchen refitted, I had to have a new consumer unit with RCDs. Now if a bulb goes ping, it puts the lights out for the whole of that lighting circuit. I think if you look at an RCCB in the wrong tone of voice, it flips (like Her Indoors).:hopelessness:

Rob

I just gave my opinion, which I regret I did.

Quote:

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Originally Posted by Clive S

I think that modern wiring dictates that you have to have the kitchen on a separate ring with RCD (could be wrong though)

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You do, a friend had a new kitchen and they put a new box in for it, seems electricians aren't required to know how to use a level, they even refused to go back and straighten up their shoddy work as it was "safe"
Luckily my new kitchen didn't require a rewire.

- Nick

Just to let you see the quasi end results.

Attachment 19252Attachment 19253

We still need to pursue the external power supply idea, but these are the demo pieces for the craft fair starting tomorrow at the old Truman's Brewery, Brick Lane EC1.

Even before the exhibition starts, we have had a lot of interest in these pieces.

Cheers,

Rob

Very nice Rob good luck at he exhibition

Looks great, I'm sure you'll get the specification sorted,
Regards,
Nick

We sold two of them at #LDF16 over the weekend. Now we have pressure to get the power supply right ! Especially as the retail price is near £1,000.
Rob