Can this IP24 rated Wall Cabinet be installed in Zone 2?

[stillp]

1) Protection of persons against access to hazardous parts inside enclosures. This is intended to cover protection of persons against accidental contact with electrically ‘live’ or otherwise hazardous mechanical parts contained within the enclosure, e.g. rotating blades, switch mechanisms etc.

What's that from John? It isn't in IEC 60529.

See page 4 of this

Kind Regards, John.

That's one of the biggest problems with IP ratings; people quote various 'guides' to the standard, which contain material that is not actually in the standard but is somebody's opinion, even if that opinion is from an august body such as EIEMA.
The standard does include a definition of "hazardous mechanical part", but doesn't use the term thereafter AFAICT. The criterion for the first digit of the IP rating is simply that the relevant probe cannot penetrate any openings.

Another problem with IEC 60529 is that manufacturers glibly quote IP ratings without specifying where they apply. For example, pushbuttons are often quoted as IP65 or better, when they can only achieve that when correctly installed in an enclosure of at least IP65. I've seen downlighters and other lampholders claimed to be IP 55, when they clearly do not restrict access to live parts if the lamp is removed, and the IP rating in that case referred to the sealing between the downlighter and the ceiling. I suspect something similar is the case with this bathroom cabinet. The manufacturer should really be more specific about where the rating applies, but many don't.

 

[JohnW2]

That's one of the biggest problems with IP ratings; people quote various 'guides' to the standard, which contain material that is not actually in the standard but is somebody's opinion, even if that opinion is from an august body such as EIEMA.

Indeed, but EIEMA seemed (to me) to be a reasonably authoritative source, which is why I assumed it was essentially correct.

The standard does include a definition of "hazardous mechanical part", but doesn't use the term thereafter AFAICT. The criterion for the first digit of the IP rating is simply that the relevant probe cannot penetrate any openings.

To be fair (to the EIEMA), I suppose that they are not actually claiming otehrwise. They are simply explaining, in that pre-amble, why the standard requires that penetration of the probe has to be prevented.

Another problem with IEC 60529 is that manufacturers glibly quote IP ratings without specifying where they apply.

Yes, that's a problem, and I think it's probably been a bit of the issue with this discussions in this thread. It seems to be a particular problem when there are 'sub-assemblies' involved. As I wrote a while back, it would seem to be daft if something which itself had a very high IP rating had to be down-rated because it existed within an outer enclosure of much lower rating.

Kind Regards, John

 

[stillp]

To be fair (to the EIEMA), I suppose that they are not actually claiming otehrwise. They are simply explaining, in that pre-amble, why the standard requires that penetration of the probe has to be prevented.

That's not what the standard is intended to do. There are other standards dealing with guarding against meachanical hazards, such as BS EN 953. I suspect that whoever wrote this for EIEMA had been confused by the optional supplementary letters, which are really there to cater for applications where for example a small quantity of water in an electrical enclosure is thrown about the inside of the enclosure by a rotating fan.

 

[JohnW2]

That's not what the standard is intended to do. There are other standards dealing with guarding against meachanical hazards, such as BS EN 953. I suspect that whoever wrote this for EIEMA had been confused by the optional supplementary letters, which are really there to cater for applications where for example a small quantity of water in an electrical enclosure is thrown about the inside of the enclosure by a rotating fan.

Oh - are you saying that BS EN 60529 is only concerned about 'electrical hazards' and 'electrical harm' and should not take into account mechanical hazards which do not impact on the ingress of dust/water into electrical parts which could thereby be harmed?

Kind Regards, John.

 

[sparkticus]

That's not what the standard is intended to do. There are other standards dealing with guarding against meachanical hazards, such as BS EN 953. I suspect that whoever wrote this for EIEMA had been confused by the optional supplementary letters, which are really there to cater for applications where for example a small quantity of water in an electrical enclosure is thrown about the inside of the enclosure by a rotating fan.

The optional/supplementary letters do cause confusion, here are two extracts from the essential guide.

5. Additional letters
Additional letters are optional and they indicate the degree of protection of persons against access to hazardous parts. Additional letters are used where:
• the actual protection against access to hazardous parts is greater than that indicated by the first characteristic numeral (for example, where greater protection is provided by barriers, suitable shape of openings or distances inside the enclosure), or
• only protection against access to hazardous parts is indicated, the first characteristic numeral then being replaced by the letter ‘X’.


6. Supplementary letters
Supplementary letters are optional. They are used to give supplementary information, the significance of which relates to the relevant product standard covering the equipment of which the enclosure forms part.

 

[sparkticus]

Oh - are you saying that BS EN 60529 is only concerned about 'electrical hazards' and 'electrical harm' and should not take into account mechanical hazards which do not impact on tare intedhe ingress of dust/water into electrical parts which could thereby be harmed?

Here is something almost definitive from the essential guide which attempts to differentiate what the IP code system provides in general VS reference to it within BS7671


The IP Code is a system given in BS EN 60529 - Degrees of protection provided by enclosures (IP code), applying to the enclosures of electrical equipment of rated voltage not exceeding 72.5 kV. The purpose of the IP Code is to indicate the degrees of protection provided by an electrical equipment enclosure against:
(i) access to hazardous parts
(ii) ingress of solid foreign objects, and
(iii) ingress of water.
The term ‘hazardous part’ in point (i) covers both hazardous live parts and hazardous moving parts. However, where BS 7671 makes use of the IP Code in its requirements, this generally relates to access to live parts, rather than access to moving parts.
[/b]

 

[JohnW2]

Here is something almost definitive from the essential guide which attempts to differentiate what the IP code system provides in general VS reference to it within BS7671 ....
The term ‘hazardous part’ in point (i) covers both hazardous live parts and hazardous moving parts. However, where BS 7671 makes use of the IP Code in its requirements, this generally relates to access to live parts, rather than access to moving parts.

OK - so does that explain how (as was raised by someone) how, as far as BS7671 is concerned, an extractor fan can have an IP44 rating by virtue of the motor enclosure, despite the fact that external to that enclosure is a rotating fan protected by the outer casing to only IP2x ?

This begs the question, of course, as to what IP claims/markings the manufacturer of such a fan is meant to utilise.

It seems to me as if this is one of those situations in which common sense is probably much more straighforward than the official ratings! - i.e. in the context that was being discussed, we want a fan whose electrical parts can't be harmed by water splashes from any direction and which does not allow a finger to come into contact with the rotating fan blade.

Kind Regards, John.

 

[sparkticus]

OK - so does that explain how (as was raised by someone) how, as far as BS7671 is concerned, an extractor fan can have an IP44 rating by virtue of the motor enclosure, despite the fact that external to that enclosure is a rotating fan protected by the outer casing to only IP2x ?

A good question. I would guess that the IP2X (outer sub-system) may apply in this case because the fan is made from plastic with a limited amount of energy (not that I want to stick my finger in and test that - and not that plastic is without danger) A metal fan blade driven by a 1/4HP motor would have a much tighter rating (let us hope) I suspect both you and indeed others on this forum would design it in accordance with a tighter IP rating as would the manufacturer who would be thinking outside the BS7671 box to that of the mechanical hazard world.

This begs the question, of course, as to what IP claims/markings the manufacturer of such a fan is meant to utilise.

For larger - responsible manufacturers - I would say largely by their own testing/risk assessments, marketing research and a degree of subjectivity - underwritten by their liability insurance -

It seems to me as if this is one of those situations in which common sense is probably much more straighforward than the official ratings! - i.e. in the context that was being discussed, we want a fan whose electrical parts can't be harmed by water splashes from any direction and which does not allow a finger to come into contact with the rotating fan blade.

Absolutely



EDIT. I also wanted to add that at first sight it seems irresponsible when you see BS7671 not directly referencing mechanical hazards in the context of IP codes, however thinking about it they need to draw the line somewhere otherwise big RED (soon to be big green) would be HUGE red/green and it may take human kind generations to interpret

 

[JohnW2]

This begs the question, of course, as to what IP claims/markings the manufacturer of such a fan is meant to utilise.

For larger - responsible manufacturers - I would say largely by their own testing/risk assessments, marketing research and a degree of subjectivity - underwritten by their liability insurance -

Maybe I wasn't clear enough, since you seem to have missed the point I was trying to make. I was assuming that all testing had been undertaken to a satisfactorily high standard, so the manufacturer knew exactly 'what size probe could reach what' and 'what sort of water attack (splashes, jets, from which directions etc.) could reach what'. However, armed with that good quality test data, what IP rating should they stamp on an extractor fan which had the electrics protected to 'IP44' but the fan blade only protected to 'IP2x'?

Kind Regards, John.

 

[sparkticus]

Maybe I wasn't clear enough, since you seem to have missed the point I was trying to make. I was assuming that all testing had been undertaken to a satisfactorily high standard, so the manufacturer knew exactly 'what size probe could reach what' and 'what sort of water attack (splashes, jets, from which directions etc.) could reach what'. However, armed with that good quality test data, what IP rating should they stamp on an extractor fan which had the electrics protected to 'IP44' but the fan blade only protected to 'IP2x'?

Apologies, I quite often miss the point and go off on a tangent. Luckily the trajectory of the tangent usually brings me crashing back to earth eventually

Yes, that is an interesting question. On first glance and taking ALL hazards into account I am bound to say the lowest, in this case IP2X. But and this is a huge but, I wonder in this case (the fan) that their "risk assessment file" may include adequate risk assessment both empirical and simulated showing that the fan can do no significant damage when properly installed in an appropriate environment/location etc, etc. Allowing them (maybe) to promote the overall product as IP 44. Phew that's a stretch. Why do I propose this as an answer? Well I do not have any experience at rating equipment for IP codes but it is the approach that I "legally" used when signing CE and EMC compliance documents for industrial products some years ago. Is it possible to draw a parallel between the two, I don't really know but If I was a manufacturers marketing dept I guess I might try.

EDIT: I forgot to mention that perhaps within their risk assessment file they clearly show that an unacceptable degradation in performance would result if the front grills were of a smaller pitch. If that is the case then clearly it would need to be tempered with the low risk of injury offered from a low power plastic fan blade (again not to underestimate the hazards of a fast moving plastic blade)
So yes the grill (sub-system) is rated unambiguously at IP2X but the likely hood and outcome of circumventing the grill, sticking a finger in after climbing up to reach it when it was on is an acceptable risk allowing the IP2X grill to be neglected in the overall IP rating declaration. The story may well and hopefully would be different with a much more powerful fan.

 

[JohnW2]

Yes, that is an interesting question. On first glance and taking ALL hazards into account I am bound to say the lowest, in this case IP2X.

That's obviously the most 'correct' approach but, as I illustrated earlier in the thread, it can get a bit silly - as I said, if you have all the 'electrics' contained in an 'inner' IP44 enclosure, but have that (and nothing else - i.e. no mechanical hazards) sitting inside an outer casing which is only, say, IP22, it would seem totally daft to have to downrate the entire product to IP22.

By requiring IPX4 (for Zones 1 & 2) and IPX7 (for Zone 0) in bathrooms, BS7671 is clearly indicating its 'lack of interest' in the mechanical protection side of the IP rating as far as specific requirements for bathrooms are concerned (although the general enclosure IP requiremenst of 416.2.1 will obviously still apply). However, if that IP44 electrical module was downrated to IP22 because of an outer casing, it would not be allowed in any zone in a bathroom - and I would struggle to see any sense in that.

Kind Regards, John.

 

[sparkticus]

By requiring IPX4 (for Zones 1 & 2) and IPX7 (for Zone 0) in bathrooms, BS7671 is clearly indicating its 'lack of interest' in the mechanical protection side of the IP rating as far as specific requirements for bathrooms are concerned (although the general enclosure IP requiremenst of 416.2.1 will obviously still apply).

Lack of interest maybe. Limiting the scope of BS7671 for reasons of not turning it into an overall specification for fixed installations more likely.

However, if that IP44 electrical module was downrated to IP22 because of an outer casing, it would not be allowed in any zone in a bathroom - and I would struggle to see any sense in that.

Exactly! and that, I think, is where the balance is struck for manufacturers to allow them to have a reasonably priced offering for a given application in a given environment. If the fan was much more powerful (plastic blade or not) then I believe they would be forced to design it very differently with an outer casing (sub-system) tighter than IP2X

 

[stillp]

Oh - are you saying that BS EN 60529 is only concerned about 'electrical hazards' and 'electrical harm' and should not take into account mechanical hazards which do not impact on the ingress of dust/water into electrical parts which could thereby be harmed?

Well, I wouldn't be that definitive about it, but the BS EN is an implementation of IEC 60529, and the 'E' in IEC stands for Electrotechnical, so that gives us a clue. One problem is that it was written as a basic standard, i.e. for use by committees writing product standards., so it falls short of defining which parts need to have an IP rating, and also doesn't define what constitutes an unacceptable ingress of dust or water. AFAIK it certainly isn't intended to define degrees of protection against mechanical hazards. However the Scope of 60529 refers to protection against contact with hazardous parts, and it then goes on to define protection against hazardous mechanical parts but without any test criteria for such protection. That would be expected to be in the product standard for fans - if there is one. I'll check when back in the office on Thursday.

 

[JohnW2]

However, if that IP44 electrical module was downrated to IP22 because of an outer casing, it would not be allowed in any zone in a bathroom - and I would struggle to see any sense in that.

Exactly! and that, I think, is where the balance is struck for manufacturers to allow them to have a reasonably priced offering for a given application in a given environment.

I'm not completely sure how that comment relates to what I was talking about - not a fan, but simply a self-contained IP44 electrical module which was within an outer IP22 enclosure.

If the fan was much more powerful (plastic blade or not) then I believe they would be forced to design it very differently with an outer casing (sub-system) tighter than IP2X

I'm again a bit confused IP2X prevents insertion of an (adult) finger, so is that not good enough? If the outer casing (grille) was tighter than IP2X, would it not seriously impede the air flow in a 'much more powerful' fan? - IP3X would limit openings to 2.5mm wide and IP4X would limit them to 1mm wide.

Kind Regards, John

 

[JohnW2]

However the Scope of 60529 refers to protection against contact with hazardous parts, and it then goes on to define protection against hazardous mechanical parts but without any test criteria for such protection. That would be expected to be in the product standard for fans - if there is one. I'll check when back in the office on Thursday.

I'm a little confused here. A standard for fans (if it exists) would presumably define what degree of protection fans require in order to comply with that standard, but I don't quite see why that should affect what IP rating BS EN / IEC 60529 would give to a fan of a particular design (whether it was compliant with the 'fan standard' or not).

Kind Regards, John