I have been round to a relatives flat and seen he has an old Wylex board with MCBs. His bathroom has no supplementary bonding from what I can see and no RCD protection for his electric shower. how potentially dangerous is this? I know the circuits are fairly short and can see main bonding in place Can only really think if the R2 values are low enough touch voltages should end up being kept low?
mapj1:
well. you need to get the human between two conductive parts at different voltages.
Now I have seen this happen with a shower actually, where a leak inside caused water to pass over the live terminals and trickle down the wall. At the same time more or less earthed water came out of the exit hose. However, both were high impedance paths and all that was reported was a bit of a tingle when leaning on the tiles and under the shower.
Amusingly having explained all this to the wide eyed friend who had been the victim, she said ‘gosh we could have 3 dead bodies in the shower!’ I pointed out that this was unlikely as I for one would not go climbing into a shower cubicle with a corpse already in it without investigating first…
There is very little risk, unless the shower has exposed metal plumbing, and modern ones do not, the modern way is that the hose is actually rubber lined and screws to a plastic fitting, and the incoming water spigot is also plastic. If the shower develops an internal leak, stop using it.
Mike
Some showers have a water pressure release valve situated in the exit pipe just before the flexible shower hose to open if the shower head gets blocked. It is sited on a nylon water tube. Recently whilst fault finding I had the experience of getting wet feet. The blinkin thing had opened and water at high pressure issued forth spraying me. To my mind the water could have entered upwards into the electrics as the water outlet is positioned against the wall tiles. I would definitely prefer R.C.D. protection there.
Here is the pressure release valve. The short spur is positioned against the tiled wall and when open spurts water in all directions.
Z.
mapj1:
well. you need to get the human between two conductive parts at different voltages.
Now I have seen this happen with a shower actually, where a leak inside caused water to pass over the live terminals and trickle down the wall. At the same time more or less earthed water came out of the exit hose. However, both were high impedance paths and all that was reported was a bit of a tingle when leaning on the tiles and under the shower.
Amusingly having explained all this to the wide eyed friend who had been the victim, she said ‘gosh we could have 3 dead bodies in the shower!’ I pointed out that this was unlikely as I for one would not go climbing into a shower cubicle with a corpse already in it without investigating first…
There is very little risk, unless the shower has exposed metal plumbing, and modern ones do not, the modern way is that the hose is actually rubber lined and screws to a plastic fitting, and the incoming water spigot is also plastic. If the shower develops an internal leak, stop using it.
Mike
Some showers have a water pressure release valve situated in the exit pipe just before the flexible shower hose to open if the shower head gets blocked. It is sited on a nylon water tube. Recently whilst fault finding I had the experience of getting wet feet. The blinkin thing had opened and water at high pressure issued forth spraying me. To my mind the water could have entered upwards into the electrics as the water outlet is positioned against the wall tiles. I would definitely prefer R.C.D. protection there.
Here is the pressure release valve. The short spur is positioned against the tiled wall and when open spurts water in all directions.
Z.
