No earth cable on light fitting

[stillp]

In that case you have no option but to follow the manufacturer's instructions. If OTOH you did understand the reasons, you would have no option but to follow the manufacturer's instructions.

Why? Nothing obliges me to obey the manufacturer's instructions.

Only common sense. Then again there's the issue of assuming liability for the performance of the product.

[I should point out that throughout this discussion I am considering 'good' manufacturers, not cheapo carp bought off the bay.]

And how is the determination made between a "good" manufacturer whose instructions one supposedly has no option but to obey, and a "bad" manufacturer whose instructions, presumably, you are saying can be ignored?[/QUOTE]No, I am not saying they should be ignored. If after consideration of the MIs a particular instruction can be proven to be wrong, then it can be discounted, provided you are prepared to accept liability for doing so. OTOH, as I've already said, if an MI can be shown to be wrong, then who knows what else might be wrong, and perhaps the product needs replacing with a better one.

 

[stillp]

[I've been participating in this discussion for a long time without actually investigating the facts.

Why let the facts get in the way of a good argument?
How common actually is it for Class II items with exposed metal parts (themselves relatively uncommon) to have this "must not be earthed" instruction, I wonder? [/QUOTE]My shower pump is an example, as is a metal-bodied bathroom cabinet with a shave socket built in as well as lights and a demister.

 

[PBC_1966]

If after consideration of the MIs a particular instruction can be proven to be wrong, then it can be discounted, provided you are prepared to accept liability for doing so..

Doesn't the same apply to a "good" manufacturer?

 

[JohnW2]

How common actually is it for Class II items with exposed metal parts (themselves relatively uncommon) to have this "must not be earthed" instruction, I wonder?

My shower pump is an example, as is a metal-bodied bathroom cabinet with a shave socket built in as well as lights and a demister.

I'm sure that there are examples but, as I said, I'm not clear as to how common. When I have a little time, I'll do a survey of some MIs. How specific/clear are these instructions, I wonder? Does "must not be earthed" mean just that one should not connect it to a CPC of the electrical installation, or does it say (or imply) that one must also avoid it coming into contact with anything earthed (like pipework) - or does it leave the reader to guess?

How does this work with your shower pump - are you allowed to connect earthed copper pipes to it?

Kind Regards, John

 

[stillp]

No. Good manufacturers don't make mistakes in their instructions, or if they did, they would accept suggestions as to how their mistakes can be overcome.

 

[JohnW2]

If after consideration of the MIs a particular instruction can be proven to be wrong, then it can be discounted, provided you are prepared to accept liability for doing so..

Doesn't the same apply to a "good" manufacturer?

Indeed. I'm sure that it is not unknown for a 'good manufacturer' (whatever that means) to produce instructions which are wrong, and certainly not unknown for a 'bad manufacturer' (whatever that means) to produce instructions that are correct.

What stillp seems to be doing, IMO very reasonably, is using his knowledge, experience and common sense to make personal judgements about the MIs (be the manufacturers 'good' or 'bad') and thereby to decide which instructions it is appropriate to 'obey' - but I don't think he would like to think of it like that!

Kind Regards, John

 

[JohnW2]

No. Good manufacturers don't make mistakes in their instructions, or if they did, they would accept suggestions as to how their mistakes can be overcome.

So might some 'bad manufacturers'. However, the issue is not about how easy it is to get incorrect instructions corrected - the point is that, no matter who the manufacturer, there is always a possibility that they are initially incorrect.

Kind Regards, John

 

[stillp]

However, the issue is not about how easy it is to get incorrect instructions corrected - the point is that, no matter who the manufacturer, there is always a possibility that they are initially incorrect.

I meant that they might endorse a suggestion from a user as to how the user might overcome the mistake, rather than correcting their instructions, i.e. if you told them the instructions were wrong and what you intended to do about it, they might tell you if that was OK or not.

 

[stillp]

How common actually is it for Class II items with exposed metal parts (themselves relatively uncommon) to have this "must not be earthed" instruction, I wonder?

My shower pump is an example, as is a metal-bodied bathroom cabinet with a shave socket built in as well as lights and a demister.

I'm sure that there are examples but, as I said, I'm not clear as to how common. When I have a little time, I'll do a survey of some MIs. How specific/clear are these instructions, I wonder? Does "must not be earthed" mean just that one should not connect it to a CPC of the electrical installation, or does it say (or imply) that one must also avoid it coming into contact with anything earthed (like pipework) - or does it leave the reader to guess?

How does this work with your shower pump - are you allowed to connect earthed copper pipes to it?

The shower pump has a sticker on it saying "Class II product - do not connect to earth", which leaves me wondering if copper pipes are allowed (mine are plastic). I don't have the full installation instructions as the cowboy who installed it threw all the instructions and packaging in a skip. The cabinet just says that "an earth connection is unnecessary".

 

[PBC_1966]

What stillp seems to be doing, IMO very reasonably, is using his knowledge, experience and common sense to make personal judgements about the MIs (be the manufacturers 'good' or 'bad') and thereby to decide which instructions it is appropriate to 'obey'

Which is, surely, what we've been suggesting we would do all along?

 

[stillp]

What stillp seems to be doing, IMO very reasonably, is using his knowledge, experience and common sense to make personal judgements about the MIs (be the manufacturers 'good' or 'bad') and thereby to decide which instructions it is appropriate to 'obey'

Which is, surely, what we've been suggesting we would do all along?

No, you've been suggesting that you would ignore the instructions, or fail to follow them. I'm suggesting that if you could prove an instruction to be wrong, you could propose an alternative. Note that you disagreeing with, or not understanding the reason for, an instruction is not a reason to discount it.

 

[JohnW2]

What stillp seems to be doing, IMO very reasonably, is using his knowledge, experience and common sense to make personal judgements about the MIs (be the manufacturers 'good' or 'bad') and thereby to decide which instructions it is appropriate to 'obey'

Which is, surely, what we've been suggesting we would do all along?

Exactly.

Kind Regards, John

 

[JohnW2]

The shower pump has a sticker on it saying "Class II product - do not connect to earth", which leaves me wondering if copper pipes are allowed ....

As I feared, but instructions which "leave you wondering" are obviously 'bad (aka useless) instructions'. Does this pump originate from a 'bad manufacturer' (since you said that good manufacturers don't produce bad instructions)? If (as I suspect) the intention is that copper pipes are allowed, that would make nonsense of the instruction that other metal parts in contact with the casing must not be earthed, wouldn't it?

The cabinet just says that "an earth connection is unnecessary".

I'm sure that I don't have to tell you that that is VERY different from saying "must not be earthed".

Kind Regards, John

 

[stillp]

Does this pump originate from a 'bad manufacturer' (since you said that good manufacturers don't produce bad instructions)?

Touche! No, it's from a market leader. However as I said I don't have the instructions, which might add clarity.

The cabinet just says that "an earth connection is unnecessary".

I'm sure that I don't have to tell you that that is VERY different from saying "must not be earthed".

[/QUOTE]
Quite. There is no provision for earthing though.

 

[stillp]

If I didn't have plastic pipes connecting the pump, I'd contact the manufacturers and see what they say. Might do that anyway.