Drain holes in IP55 enclosures?

[Nemo2000]

I've bought a couple (to see which size is better for my needs) of IP55 enclosures (British General brand) in order to be able mount the transformer for my 12V garden light outside, albeit with the 230V feed coming from a socket indoors.

What puzzle me is that instructions specify drilling out a drain hole (location dependant upon the orientation of the cable entries), yet then say that making a drain hole will affect the IP rating. So if you must (as they imply) have a drain hole and that then means the box is no longer IP55, how can they advertise it as IP55 in the first place? And is a drain hole really necessary anyway - I've yet to come across any outdoor fittings anywhere else that actually have one.

 

[JohnW2]

What puzzle me is that instructions specify drilling out a drain hole (location dependant upon the orientation of the cable entries), yet then say that making a drain hole will affect the IP rating. So if you must (as they imply) have a drain hole and that then means the box is no longer IP55, how can they advertise it as IP55 in the first place?

That's a good question, which I've often wondered about.

And is a drain hole really necessary anyway - I've yet to come across any outdoor fittings anywhere else that actually have one.

The reality is that even items with 'high' IP ratings have been known to fill up with water - so, yes, drain holes do seem to be a good idea.

Kind Regards, John

 

[SUNRAY]

That's a good question, which I've often wondered about.

The reality is that even items with 'high' IP ratings have been known to fill up with water - so, yes, drain holes do seem to be a good idea.

Kind Regards, John

One of the sources of the water is condensation. As the temperature rises the air expands inside and some 'escapes', as it cools the air contracts and sucks fresh air in, including any moisture.

With the best will in the world it is very difficult to make an electrical enclosure totally air tight so yes drill a drain hole.

On a job I did just that but it got snagged and I had to replace them, in doing so I put in writing I would not accept responsibility for any moisture and I'm glad I did as one developed RCD tripping issues.

The only issues I've encountered with drain holes are bugs finding a cosy home and plants find them and continue growing inside. I believe both of those are far better than the damage created by water.

 

[pete01]

Dont drill a hole fit a vent plug.

 

[SUNRAY]

Dont drill a hole fit a vent plug.

If I think about it at the time I place an offcut of wire so it nearly fills the hole. Not the same as a smaller hole.

 

[JohnW2]

One of the sources of the water is condensation. As the temperature rises the air expands inside and some 'escapes', as it cools the air contracts and sucks fresh air in, including any moisture.

True.

With the best will in the world it is very difficult to make an electrical enclosure totally air tight ...

Again, probably true. However, if it can't be made 'totally air tight", it's unlikely to be totally water tight, either. So, as we have both said ....

.... so yes drill a drain hole.

However, as I replied to him, I have a lot of sympathy for the OP's question. IPX5 requires "protection against water projected from a spray nozzle (or jet of low-pressure water stream) at any angle" - and if one drills a hole of any significant size in the bottom of an enclosure, I'm not sure that requirement is likely to remain satisfied, is it?

Indeed, if the MI's for an IPX5 enclosure require that a drainage hole be drilled (presumably 'always'), why isn't that done during manufacture - in which case the manufacturer could test it 'with the hole' and therefore determine whether they could legitimately sell it (with the hole) as "IPX5".

Kind Regards, John

 

[SFK]

Condensation has always been an issue with 'laser welded, hermetically sealed, dry gas filled' cases that should never ever let mositure in (but always eventually did).

So with that in mind I have always drilled out the drain hole in the back my IP enclosures with a 1mm or 2mm drill, drilled with a downward angle to the outside.

Never had condensation or water issue with multiple IP sockets.

But have once had ants presumably use that hole to gather to get warm (and fry) arround the neon on/off indicator of the socket and trip the circuit

SFK

 

[SFK]

. duplicate.

 

[ericmark]

IP 55 = Ingress of dust is not entirely prevented, but it must not enter in sufficient quantity to interfere with the satisfactory operation of the equipment. + Water projected by a nozzle (6.3 mm (0.25 in) against enclosure from any direction shall have no harmful effects.

As to if still IP 55 would depend on size of hole drilled, it can be very small, as @SUNRAY says, as the air expands then contracts air is sucked in, and water if it is sitting on any joint with slightest of leak, and capillary action tends to mean there is water on any joints, but the pressure with blows out air or sucks it in will do so even with a ½ mm hole, so the hole can be very small so does not affect the IP rating.

 

[Nemo2000]

The manufacturer's instructions state to drill a 5mm drain hole

 

[ericmark]

That seem a bit large, 1 mm and over would change IP rating.

 

[EFLImpudence]

If it works satisfactorily it doesn't matter what the IP rating is.

 

[SUNRAY]

I have found that condensation is worse with a smaller hole, My 'go to' is a bigger hole then bend a bit of wire (usually a core of T&E with insulation)to hang in the hole. The drill is say 1mm bigger than the wire which essentially gives a gap <1mm but being a ring provides more area than just a 1mm drill.

 

[securespark]

If I can, I fill the enclosures with magic gel, thus excluding air and moisture from any terminations.

I remade the connections in an underground enclosure on my Mum's outside lighting at least 10 years ago and it has been tickety-boo ever since.

 

[JohnW2]

That seem a bit large, 1 mm and over would change IP rating.

That was my point, and the OP's.

If the MIs say that a 5mm hole must always (or even just 'usually') be drilled, then it seems unlikely that they are correct in claiming (implying) that ('when used as instructwd') it is still IP55.

Kind Regards, John