Socket under sink

[JohnW2]

It's permitted but IMO undesirable. I'd consider swapping it for a weatherproof "outdoor" one with the cable entering from underneath and a lid that will shut with a plug in it.

As has been said, I don't really understand the excitement about sockets under sinks - or,to put it the other way around, why there is not similar excitement about electrical accessories in all sorts of other places.

I think I've always had sockets and/or FCUs and/or JBs /whatever under, or nearly under, kitchen sinks, and in very close proximity to all sorts of water and waste plumbing, but don't recall any case of a resultant problem. On the other hand, over the decades I have had a fair number of instances of accessories in other locations 'filling up with water (due to plumbing, CH or roof leaks - and even an overflowing bath on one occasions ) - including ceiling roses/light fittings, sockets, FCUs, JBs light switches and even CUs. Do you think I should have installed weather-resistant "outdoor" accessories throughout my house?

Kind Regards, John

 

[RandomGrinch]

Purity matters!
We once had an RO (reverse osmosis) water filter system fail, and leak a (relatively) large amount of water over trunking and down a service duct containing the buildings bus bar risers.
It didn't matter too much, when the water had a resistivity of 18MΩ-cm

 

[JohnW2]

Purity matters! We once had an RO (reverse osmosis) water filter system fail, and leak a (relatively) large amount of water over trunking and down a service duct containing the buildings bus bar risers. It didn't matter too much, when the water had a resistivity of 18MΩ-cm

Hmmm. It may have been extremely pure 'at source', but I wonder how pure it still was, and how high it's resistivity was, by the time it had completed that journey through (presumably) dusty/dirty trunking and service duct - I think that it takes very little contamination to fairly dramatically increase the conductivity of 'pure water'

Kind Regards, John

 

[RandomGrinch]

Hmmm. It may have been extremely pure 'at source', but I wonder how pure it still was, and how high it's resistivity was, by the time it had completed that journey through (presumably) dusty/dirty trunking and service duct - I think that it takes very little contamination to fairly dramatically increase the conductivity of 'pure water'

Kind Regards, John

The trunking was directly below the failed tank in a semi-cleanroom - so not too much contamination at that point - we were slightly concerned for the bus bars though!

 

[JohnW2]

The trunking was directly below the failed tank in a semi-cleanroom - so not too much contamination at that point - we were slightly concerned for the bus bars though!

Fair enough.

What was in my mind was a demonstration I saw decades ago - there was a large (I presume glass or plastic) tank/trough containing very pure water, with resistance being measured across it. Just one drop/drip of something (maybe just brine) was dropped into the tank, remote from the electrodes, and almost immediately the measured resistance dropped into its boots!

In passing, I've always found the term 'Reverse Osmosis' a little odd, since I can't see that there is anything 'reversed' about the osmotic process. It's really just a question of whether one's 'interest' lies in what ends up on one side or the other of the membrane - so if one's interest was in the dissolved constituents, rather than the residual water itself, would one call that "forward osmosis"?

Kind Regards, John

 

[RandomGrinch]

In passing, I've always found the term 'Reverse Osmosis' a little odd, since I can't see that there is anything 'reversed' about the osmotic process. It's really just a question of whether one's 'interest' lies in what ends up on one side or the other of the membrane - so if one's interest was in the dissolved constituents, rather than the residual water itself, would one call that "forward osmosis"?

I'm afraid that osmosis (or reverse osmosis), in this case refers to the process, rather than the outcome.
In 'Forward' osmosis, the solvent passes naturally through the semi-permeable membrane to dilute the solute until the osmotic pressure is equalised.
With 'Reverse' osmosis, we apply enough pressure to overcome the osmotic pressure and force the solvent out of the solute. The semi-permeable membrane is also designed to limit the size of the molecules that can pass through it.
Do you want to dilute the solute, or concentrate it? - that seems pretty reversed to me

 

[JohnW2]

I'm afraid that osmosis (or reverse osmosis), in this case refers to the process, rather than the outcome.

Fair enough.

In 'Forward' osmosis, the solvent passes naturally through the semi-permeable membrane to dilute the solute until the osmotic pressure is equalised.

Indeed so.

With 'Reverse' osmosis, we apply enough pressure to overcome the osmotic pressure and force the solvent out of the solute. The semi-permeable membrane is also designed to limit the size of the molecules that can pass through it.

Fair enough, but I think I would probably call that "ultrafiltration", not any sort of 'osmosis'.

Kind Regards, John

 

[RandomGrinch]

Fair enough, but I think I would probably call that "ultrafiltration", not any sort of 'osmosis'.

Good point, maybe "anti-osmosis, ultrafiltration"

 

[JohnW2]

Good point, maybe "anti-osmosis, ultrafiltration"

As I said/implied, I am personally inclined to say that to include the word "osmosis" at all is meddlesome, unnecessary, potentially confusing and 'unhelpful'

Filtration under pressure is ubiquitous, whether the 'things being held back by the filter' are at the molecular/virus level or much larger - and 'osmosis' doesn't come into any of that.

I don't know how the mechanics of "RO" works, but with filtration under pressure, the fluid downstream of filter is usually minimally in contact with the filter, so that the question of an 'osmotic pressure' (tending to make the solvent move in the opposite direction to what one wants) doesn't usually really arise.

Kind Regards, John