The Lamp Room

Check out this bad boy

Those suicide showers are more common than you think!

Yeah they're great aren't they!

They are like 10kw or something too.... not sure those cables are up to that!

Nowhere near up to it - I've had a good look at it and the supply cables are literally half the thickness of the cables coming out of the unit itself. I'm expecting the supply cables to become a nice bathroom heater when its in use

they're water cooled so they will be alright

I can't see a earth wire... I saw a teardown of one of these and the earth wire was bare and just sat in the flow of the water inside.

Would one of these even work in a UK house with sensitive RCDs?

I have been investigating this today. The unit is reliant on the earth as both the naked bare wire element and earth are submerged in the water during use. This one has an earth point on the outside of the unit (out of shot on picture) which is unmissable and clearly labelled as must be connected, yet has not been connected, meaning it was installed by someone incompetent, and it is hard wired using incorrect thickness cables with an exposed chock block to a switch with no circuit breaker on the main board in the building (I traced it back). Due to these factors - most importantly the lack of connected earth point, the fact that it is switched via a water diaphragm switch which connects both L and N points unevenly (meaning element could be live without a neutral return connection if the diaphragm switch doesn't close perfectly level) and the fact that if the element fails and breaks it is literally putting live exposed wires in to water with no earth/escape path other than through the emitted water and anyone it touches, I will absolutely not be using this unit for anything other than filling buckets with hot water to wash with. The climate here is such that cold showers are really nice and refreshing anyway and the water is swimming pool temperature when unheated thanks to the climate, so its really not an issue to simply switch it off and shower using cold water. In conclusion, the fact is that it will work and will not kill you ...UNLESS any one of a multitude of factors mentioned above fail on it, at which point you're screwed. Long answer but in conclusion I won't be risking it.

I think the main reason why they dont shock (all that much) is not related to the Earth connection but to other things :

1. The water exits the device as a spray of droplets. There is no continuity from it to your head if it is installed high enough above (so that the water stream stays broken up), and the water pressure is sufficient to get a spray and not just pouring water. You might be in for a Pikachu if you reach to it for the switch however...

2. The temperature at the interface between the heater and water volume maybe makes the water boil, so create a steam layer separating the water from the heater and reducing the contact area. (I dont think a dangling end of a stripped Earth wire, with surface area 100x less than the heater, would do anything to change the average potential of the water volume otherwise)

I'd expect this thing to be somewhere around 3..5kW. If operated in short bursts (as it will likely be), 0.75mm2 or 1.5mm2 wire respectively would just about survive it. I'd guess there might be a common knowledge among the locals that electrical showers are meant to only be operated in short bursts, so they get away with using showers on undersized wiring. Then an oblivious guest expecting to run it continuously for a first world hot shower could possibly start a fire

I think you could be right there. I'm not an expert on resistance and the exact science of what one might get away with every time, and all the points you've made are good points and likely what makes it work, just my first world mentality makes me scream 'f**k that'. I mean I've used this type of shower over the years as I've done a hell of a lot of travelling and never given it much thought, but seeing it without an earth, very close to one's head when showering and the fact that I don't really need to use it in this climate makes me think I won't bother.

Its interesting to explore how they work though, I never really gave much thought to what is inside those things before now

You'll be fine with no earth as long as the waste pipe is plastic