Bathroom circuit for heated mirror from redundant immersion circuit

[JohnD]

the reference to zone 2 means that water splashes are possible, hence the water-resistance IP rating is relevant. An ordinary FCU doesn't have any particular water resistance, and drips or splashes on the wall can run down behind the faceplate. I would consider it not to be IPX4 unless there was evidence proving otherwise.

I don't understand your point.

 

[JohnW2]

IPX4 – Protects from splashing water, no matter the direction. .... Are you thinking of IP4X?

Only EFLI can (and presumably will) tell you what he was thinking of but, in passing, one observation/comment ....

I think that there is a tendency to think that the 'X' in, say, IP4X and IPX4 can be 'anything', but I don't think that can, in practice, be true...

... I find it hard to see that anything could have a "4" for 'water ingress protection' (the second digit) if the 'mechanical protection' one (the first digit) was not also at least 4, maybe higher. In other words, I suspect that the minimum IP rating that would "protect from splashing water, no matter the direction" would probably be IP44, maybe even higher. Conversely, I somewhat doubt that it would be possible for the 'X' of, say, IP5X to be less than about 4.

Kind Regards, John

 

[JohnD]

I think I saw IP44 on my bathroom fan, which seemed fair. The switch is outside zones.

 

[JohnD]

with the FCU located just below the ceiling

How high is the ceiling? 2400mm is common in modern houses, so a switch can be outside zones.

 

[JohnW2]

.... An ordinary FCU doesn't have any particular water resistance, and drips or splashes on the wall can run down behind the faceplate. I would consider it not to be IPX4 unless there was evidence proving otherwise.

That's fair enough, but I suspect EFLI's point was that something does not necessarily have to be 'designed to be IPX4' (or marked as IPX4) in order to actually satisfy the requirements for being IPX4.

Kind Regards, John

 

[JohnW2]

How high is the ceiling? 2400mm is common in modern houses, so a switch can be outside zones.

If I understand correctly, I think that's the OP's point - that if he is told that he cannot have the FCU in zone 2, that he will ('reluctantly') put it near the ceiling, out of zones.

Kind Regards, John

 

[JohnD]

There are some people who think that a washbasin has zones, hence I attached the pic. My wall around the bathroom washbasin is littered with wall lamps, shaver outlets etc, but is on the far side of the room from bath and shower, so outside zones.

 

[JohnW2]

I think I saw IP44 on my bathroom fan, which seemed fair.

That makes sense since, as I said, I doubt that it would be possible to make something which was IP24 or IP34.

Another 'in passing' ... I have always found it intuitively rather surprising that IPX4 requires protection against 'splashes', whereas IPX2 and IPX3 require protection against 'direct sprays' (at different angles) - since my intuition would have expected 'direct sprays' to be more likely to penetrate an enclosure than a 'splash'!

Kind Regards, John

 

[JohnW2]

There are some people who think that a washbasin has zones, hence I attached the pic.

There are such people - indeed, a good few sources of that false information (with diagrams) which probably appear to many to be be fairly 'authoritative'.

I don't know the history of this - was there ever a 'zone' around a basin, I wonder?

Kind Regards, John

 

[JohnD]

I remember many years ago a builder working as an electrician who told me that sockets should be (he gestured a fathom) away from the kitchen sink because you might have one hand on the tap and one on the wet plug.

I believe it was an unofficial interpretation of the "suitable for where it is" guideline.

He also used to earth-bond sinks.

he also said it was OK to have junction boxes without lids under the floor, relying on the "out of reach" rule (that I have now forgotten) used to justify busbars in overhead equipment. I disagreed.

Considerably later, I was repairing a floor and nearly put my hand on one of his lidless junction boxes.

 

[JohnW2]

I remember many years ago a builder working as an electrician who told me that sockets should be (he gestured a fathom) away from the sink because you might have one hand on the tap and one on the wet plug.

I must say that that is probably at least as reasonable an argument (even though not a reg) as the argument (which is a reg) that switches must not be within 600mm of the edge of the bath.

Sockets are rather different - I can but assume that the '3m rule' is an attempt to deter people from using plugged-in electrical appliances whilst in the bath/shower!

Kind Regards, John

 

[flameport]

I don't know the history of this - was there ever a 'zone' around a basin, I wonder?

No.

The basin zone originated in this or an earlier version of it: https://www.downlights.co.uk/media/...ontaining-a-bath-or-shower-pdf-1376904504.pdf
where the LIA recommended to it's members (who are mostly lighting manufacturers) that certain types of luminaires should not be installed close to basins, and created a 'LIA IPX4 Area' around the basin and intended it to be considered as zone 2.
Nothing wrong with that - BS7671 only gives the minimum standard required.

After that, one or more manufacturers instructions appeared with the same diagram but with 'LIA IPX4 Area' replaced with 'Zone 2', which is incorrect. Much copy and paste later with a few alterations shoved in for good measure, and incorrect diagrams showing various permutations of zone 2 around basins are everywhere.

 

[EFLImpudence]

the reference to zone 2 means that water splashes are possible, hence the water-resistance IP rating is relevant.

Admittedly not all such tables include the last sentence but I presume it must be true.

An ordinary FCU doesn't have any particular water resistance,

Well, it is plastic with very a narrow gap around the plastic fuse holder.

and drips or splashes on the wall can run down behind the faceplate.

They could but a very poor installation on an uneven wall.

I would consider it not to be IPX4 unless there was evidence proving otherwise.

Even if you are correct, would it take much to make it so.

I don't understand your point.

My point is, as John has said, because something is not marked IPX4 does not mean it isn't.


You did not answer my question regarding the flex outlet plate.

If you consider that prohibited, then what about, as I have advised before, having a flex outlet plate (for neatness) but have the cable passing through it unbroken to an FCU on the other side of the wall? It's still an accessory not marked IPX4 yet a hole in the wall would be alright.

 

[flameport]

The deal with FCUs is that they are usually IP2X, Crabtree example: https://storage.electrika.com/manu/man-0170/pdftech/cr1827.pdf
X meaning undefined, so in a situation which requires IPX4, a product which meets IP2X is of no help whatsoever.

 

[EFLImpudence]

Does that not mean that they have not considered the water rating because it has a switch?