Safety issue with domestic appliance

[ericmark]

Most has already been answered.
The main thing to consider many things are dangerous if installed or used in a way not intended by the manufacturer, be it a car, or even screwdriver they can be lethal weapons but that is incorrect use of the item.

So if when hot there is a short to earth then this will not injure anyone as long as installed following the IET/BSi regulations, it may be a pain where it causes the power to trip, but only a danger if incorrectly installed.

As to 32 or 45 amp feeds to an oven that has been up for debate many times, on a fixed appliance the manufacturer can stipulate the protective device, although not with a portable appliance. So the manufacturer can say this device should be protected to 16A. Where the manufacturer has not stated it should be protected with a 16A device we have to look as what is reasonable. The first point has to be supply cable, for 32A would need to be 6mm² and for 45A would need to be 10mm² in the main you would struggle to use cable that thick in the main ovens are wired with 2.5mm² cable so the overload would be no more than 20A.

If anyone was to wire a oven with 10mm² and something in the oven melted or failed including the earth cable, I could not see a court blaming the manufacturer they would likely blame the installer for using over sized cable and overload. But it would be for the courts to decide. 20A feed to an oven OK, but even 32A is double the size required, so although people may do it, they shouldn't.

It is like saying you need to lower the speed limit from 40 to 30 because there have been so many accidents due to people driving at 60. The fault is people driving over the speed limit, not the speed limit set to wrong level.

From what you say there is a fault which needs correcting, which may warrant a recall, and trading standards may be interested and also the manufacturer may do a recall anyway. But if you tell people it is dangerous when it's not, then they will likely ignore what you say, one has to be careful not to over state what the faults are.

What make of Oven is it? And pictures would be good. Then even if the manufacturer does not correct it will alert people. We all see the reports on Hotpoint tumble driers and we avoid that make.

 

[JohnW2]

Most has already been answered. ... So if when hot there is a short to earth then this will not injure anyone as long as installed following the IET/BSi regulations, it may be a pain where it causes the power to trip, but only a danger if incorrectly installed.

Indeed - but, to just reiterate, that "following regulations" must include providing RCD protection if it is a TT installation - otherwise there would be a risk of a 'short to earth' (short from L to case of oven) resulting in injury or death.

Kind Regards, John

 

[EFLImpudence]

The first point has to be supply cable, for 32A would need to be 6mm² and for 45A would need to be 10mm²

Not so.

in the main you would struggle to use cable that thick in the main ovens are wired with 2.5mm² cable so the overload would be no more than 20A.

If anyone was to wire a oven with 10mm² and something in the oven melted or failed including the earth cable, I could not see a court blaming the manufacturer they would likely blame the installer for using over sized cable and overload. But it would be for the courts to decide. 20A feed to an oven OK, but even 32A is double the size required, so although people may do it, they shouldn't.

Just not so.

 

[stillp]

AMDEA might be worth a try, but they seem to be a consumer group looking at their website.

They are the Association of Manufacturers of Domestic Electrical Appliances.

 

[stillp]

Trading standards say it is not their area.

Do you mean their geographic area? It is certainly the responsibility of the Trading Standards department of the Local Authority to enforce the General Product Safety Regulations 2005 - see http://www.legislation.gov.uk/uksi/2005/1803/regulation/10/made

 

[jj4091]

Thanks stillip, a phone call to local office proved unresposive. I wiil go to a larger office & quote the legislation to them. Perhaps that will make them be more interested. Thanks to all respnders, but I just wanted the sort of info stillip has provided rather than a discussion about whether I was correct or incorrect, I know it was all done with the best intentions. Thank you.

 

[ban-all-sheds]

AMDEA might also be interested.

Do we know that the manufacturer is a member?

If not, I imagine the only interest they would have would be self-promotion.

 

[JohnW2]

Thanks to all respnders, but I just wanted the sort of info stillip has provided rather than a discussion about whether I was correct or incorrect, I know it was all done with the best intentions.

Fair enough, but it hasn't been just an academic discussion. If you want to be taken seriously by whoever you report this issue to, you need to be able to give them a clear and credible explanation of what you have observed. That is why I asked you how you had ascertained that the case of the oven becomes 'live' when it heats up - and, indeed, what you mean by 'live' - can you gives us a little more insight into that?

As a side issue, I have also pointed out to you that, with the earthing arrangements that are most common, it would not be possible for the case of the over to become significantly 'live' unless there was something potentially dangerous wrong with your house's electrical installation. That is why I asked what sort of earthing system you have - do you know if it is an earth provided by your electricity supplier on one which uses an 'earth rod' in the ground outside of your house?

Kind Regards, John

 

[jj4091]

Fair enough, but it hasn't been just an academic discussion. If you want to be taken seriously by whoever you report this issue to, you need to be able to give them a clear and credible explanation of what you have observed. That is why I asked you how you had ascertained that the case of the oven becomes 'live' when it heats up - and, indeed, what you mean by 'live' - can you gives us a little more insight into that?

As a side issue, I have also pointed out to you that, with the earthing arrangements that are most common, it would not be possible for the case of the over to become significantly 'live' unless there was something potentially dangerous wrong with your house's electrical installation. That is why I asked what sort of earthing system you have - do you know if it is an earth provided by your electricity supplier on one which uses an 'earth rod' in the ground outside of your house?

Kind Regards, John

John, I am not talking about the particular installation where I discovered the problem, but the totally avoidable risk in other possible scenario's which I nor anyone else would have control over. Even if the oven has not been installed correctly, as you say, I feel that they should at least make other maintenance people who may come into contact with these ovens aware of the risk, but even better resovle the issue with what will probably be a few pence modification.
I am genuinely concerned about other peoples safety rather than just trying to cause a fuss & feel that as the manufacturers do not seem interested then I MUST take it further.

 

[JohnW2]

John, I am not talking about the particular installation where I discovered the problem, but the totally avoidable risk in other possible scenario's which I nor anyone else would have control over.

I realise that but, as I said, for your own/others' personal safety, I was (additionally) pointing out that if, in the particular installation in question (I assumed your home, but I may be wrong), the case of the oven is becoming significantly 'live', then, IF that installation had a supplier-provided earth, then there is something dangerously wrong with either the installation or the way in which the oven has been installed - and that, if that were the case, it would need urgent attention.

Even if the oven has not been installed correctly, as you say, I feel that they should at least make other maintenance people who may come into contact with these ovens aware of the risk, but even better resovle the issue with what will probably be a few pence modification. I am genuinely concerned about other peoples safety rather than just trying to cause a fuss & feel that as the manufacturers do not seem interested then I MUST take it further.

Yes, I also understand that, and I commend you for your public-spirited intentions. However, you still have not told us any details of the nature of what sounds like a design fault and, in particular, how you have ascertained that the case 'becomes live' (and how 'live' it becomes). As I've said, if you do not tell those things clearly to whoever you report the matter to, they are unlikely to take your report seriously, so I would have thought that you would also be able to tell us.

Kind Regards, John

 

[securespark]

I was told you can’t have earth electrodes with a TN system

Wait till the 18th....!!

 

[stillp]

Do we know that the manufacturer is a member?

If not, I imagine the only interest they would have would be self-promotion.

If not then they will make a more effective investigation and report, which would benefit their members.

 

[ban-all-sheds]

OK - I guess I wasn't aware that trade associations used their members' money to investigate complaints about things made by someone who was not a member, except in the context of self promotion and/or lobbying for some kid of statutory status.

 

[ban-all-sheds]

John, I am not talking about the particular installation where I discovered the problem, but the totally avoidable risk in other possible scenario's which I nor anyone else would have control over. Even if the oven has not been installed correctly, as you say, I feel that they should at least make other maintenance people who may come into contact with these ovens aware of the risk, but even better resovle the issue with what will probably be a few pence modification.
I am genuinely concerned about other peoples safety rather than just trying to cause a fuss & feel that as the manufacturers do not seem interested then I MUST take it further.

It's really quite simple.

If it is a Class I appliance, then all the exposed-conductive-parts (such as the casing) will be earthed. This is because they could indeed become live in the event of a fault within the appliance. If there are no problems in the electrical installation then the supply to the device will be interrupted before the voltage on the casing becomes dangerous - that's the whole point, that's why there are requirements for devices to act within a certain time, and requirements for maximum fault loop impedance.

If a fault makes the item hazardous if there is inadequate earthing then the problem does not lie in, nor is the responsibility of the maker of, the item.


OTOH, if it is a Class II appliance, then the casing becoming live is a problem for which the maker is responsible.

 

[JohnW2]

If a fault makes the item hazardous if there is inadequate earthing then the problem does not lie in, nor is the responsibility of the maker of, the item.

Whilst I agree with most of what you say, I can't really agree that it is not the maker's responsibility if there is a design or manufacturing fault which results in the case of the appliance becoming connected to the 'live' supply.

As we have both said, in a satisfactory installation it should not be possible for the case of a Class I item to 'remain live' for a significant period of time, even if there is such a fault. However, I that doesn't mean that the manufacturer does not need to take 'reasonable steps' to avoid such a fault arising.

In the case of this thread, despite my trying quite hard to get it, we have not received any information about the nature of the alleged fault, nor an explanation of how the OP determined that the case becomes 'live' when the oven is hot (or an indication of 'how live').

Kind Regards, John