Class I or Class II ?

[EFLImpudence]

Is it Class II? No, because it has an earth connection, and so will not bear the Class II construction mark. It's definitely Class I.

I don't think it follows that, because it is not class II, it therefore is class I.

It does not meet the definition of class I either.

The fact that it has an earth connection is not the criterion.
The criterion is what is done with exposed conductive parts.

This is the whole point of John's original question - How are such items classed? - which no one seems able to answer.

 

[stillp]

7.2 Class I equipment
Equipment with basic insulation as provision for basic protection and protective bonding as
provision for fault protection.

I'm beginning to think I should have just posted all the text of EN 61140!

 

[JohnW2]

I don't think it follows that, because it is not class II, it therefore is class I. It does not meet the definition of class I either.

Quite so. As I understand it, to be 'legal' it has to satisfy the requirements of Class I, II or III (Class 0 already have been outlawed). On the face of it, the (very many) plastic enclosed items we're talking about must regard themselves as Class II (usually achieved by 'reinforced', rather than 'double', insulation) - since, to my mind, they could never satisfy the requirements of Class I.

This is the whole point of John's original question - How are such items classed? - which no one seems able to answer.

Indeed.

Kind Regards, John.

 

[JohnW2]

7.2 Class I equipment
Equipment with basic insulation as provision for basic protection and protective bonding as provision for fault protection.

Exactly as I've always understood - which puts paid to this rather strange suggestion that an all-plastic item with no involvement of a CPC in fault protection should be regarded as Class I !!

Kind Regards, John.

 

[stillp]

You've lost me John. Where is that suggestion made?

 

[JohnW2]

You've lost me John. Where is that suggestion made?

About a page back....

How can an all plastic item be Class I if there is nothing to which a cpc can be connected?

An earth connection may be used for purely functional, rather than protective purposes, so wouldn't be a cpc....Is it Class II? No, because it has an earth connection, and so will not bear the Class II construction mark. It's definitely Class I.

Kind Regards, John.

 

[Grizzly]

However, they are definitely not Class II, or they would bear the construction mark.
Nor are they Class III, obviously

So what class does that leave?

A general rule given in the IEE COPISTEE is 'if it is not known whether an item of equipment is Class I or Class II, it should be treated as Class I'.

 

[Spark123]

If you came across an appliance with a double insulated sticker but was metallic an had an earth wire would you earth it (the appliance case verified as being connected to the CPC)?

 

[Grizzly]

No, I wouldn't.
I'd fail it (if doing 'PAT'), and be on to the manufacturers to investigate the contradiction.

 

[JohnW2]

A general rule given in the IEE COPISTEE is 'if it is not known whether an item of equipment is Class I or Class II, it should be treated as Class I'.

... but what does "treating it as Class I" mean? The only 'treating as Class I' I can think of is to connect its exposed-conductive-parts to the CPC of fixed wiring (i.e.'earthing' them), but if there are NO exposed-conductive-parts, what would you actually do?

I strongly suspect that, despite what you say/quote, you would actually and effectively treat it as Class II - indeed, I don't think you'd have any other option !!

Kind Regards, John.

 

[JohnW2]

If you came across an appliance with a double insulated sticker but was metallic an had an earth wire would you earth it (the appliance case verified as being connected to the CPC)?

I guess this brings us to the question of what it is, where it is to be used and why it's double insulated ...

For equipment to be sited/used within the equipotential zone of an installation, there's no harm I can think of in earthing any exposed-conductive-parts whether the equipment is double-insulated or not.

It's only if we get onto the 'old cherry' of a PME earth 'exported' outside of the equipotential zone, particularly if in the vicinity of true earth (e.g. with electrical garden tools) that an issue really arises - and the issue then is not really anything to do with the insulation/safety of the equipment, per se, but, rather, the potential (extremely small) danger associated with being able to come into contact with a PME earth when outside the equipotential zone (and particularly when standing on soil with bare feet!).

Kind Regards, John.

 

[Risteard]

A general rule given in the IEE COPISTEE is 'if it is not known whether an item of equipment is Class I or Class II, it should be treated as Class I'.

... but what does "treating it as Class I" mean? The only 'treating as Class I' I can think of is to connect its exposed-conductive-parts to the CPC of fixed wiring (i.e.'earthing' them), but if there are NO exposed-conductive-parts, what would you actually do?

I strongly suspect that, despite what you say/quote, you would actually and effectively treat it as Class II - indeed, I don't think you'd have any other option !!

Kind Regards, John.

I suspect he meant that the combined inspection and testing should be conducted as if it were a Class I asset.

 

[JohnW2]

I suspect he meant that the combined inspection and testing should be conducted as if it were a Class I asset.

Maybe, but I'm not sure I would understand quite what that meant, either! In the context of this discussion, I would have thought that the most important part of the I&T of an item of Class I equipment would be to confirm a satisfactory connection between the exposed-conductive-parts and the installation's CPCs. If there are no exposed-c-ps, that clearly cannot be done.

What other things were you thinking of that would be involved in the I&T of a Class I item that would not be done for a Class II one?

Kind Regards, John.

 

[Grizzly]

I strongly suspect that, despite what you say/quote, you would actually and effectively treat it as Class II - indeed, I don't think you'd have any other option !!

No, I wouldn't.

FWIW, and even though I quoted it, I'm not a great fan of the 'treat as Class I' rule.
But nor would I automatically treat anything that has no exposed-conductive-parts as Class II either.

For one thing, the IR tests are different for Class I and II, in in-service I&T.
Doing a Class II IR test on a completely insulated item, that you knew had an earth going in, would be pointless, but a Class I IR test would be better, even though you wouldn't have been able to do an earth continuity test previously.

It is a rather hateful grey area.

 

[JohnW2]

FWIW, and even though I quoted it, I'm not a great fan of the 'treat as Class I' rule. But nor would I automatically treat anything that has no exposed-conductive-parts as Class II either. For one thing, the IR tests are different for Class I and II, in in-service I&T. Doing a Class II IR test on a completely insulated item, that you knew had an earth going in, would be pointless, but a Class I IR test would be better, even though you wouldn't have been able to do an earth continuity test previously.

I must be being a bit dim. Can you explain what this 'Class I IR test' on a completely insulated item would consist of, and how you would do it? Thanks.

Kind Regards, John.