"Steven Watkins" wrote in message
news
On Sat, 10 Nov 2018 21:13:55 -0000, Rod Speed
wrote:



"Steven Watkins" wrote in message
news
On Sat, 10 Nov 2018 20:35:25 -0000, Rod Speed
wrote:



wrote in message
...
On Saturday, November 10, 2018 at 10:33:19 AM UTC-5, Steven Watkins
wrote:
Why do houses have a switch to turn the shower off, either a cord on
the
ceiling or a switch in the hall?

Can you please describe the situation more fully. Does this switch
turn
off
the water, or does it turn off electricity (such as for a light in the
shower compartment)?

It turns off the electrical heating of the water in the shower.

Some not in england go even further
https://www.youtube.com/watch?v=cNjA0aee07k

I can't understand how that can work with no earth.

Basically there is far less water between the active
and neutral than between the active and any earth
that the person in the shower can be in contact
with even with metal water supply pipes and taps.

Irrelevant.

Nope.

Think of it as two resistors in series (the element and the person).

Nope, they arent in series if there is an element.

You have live at one end of the element, 240V. This is free to conduct
through a few inches of water to the shower head holes, then through the
person underneath.

In practice the resistance that way is quite high, even
if the person in the shower is holding a metal tap
which has an earthed metal water pipe behind it.

Having the element conduct electricity from that 240V point to neutral
doesn't change the voltage by much at the 240V end,

Correct.

so the same current will flow through the person underneath.

No it wont, because the resistance thru the water is much higher.

Is the water coming out of the shower when unearthed not at about 120
volts

Nope, most of europe and china are 240V

I was assuming the middle of the element was close to the outlet.

That really doesn't matter given the high resistance of the water.

(the average of the heating element voltage)?

There is no heating element. The
current flows thru the water itself.

Your video showed a coiled wire, this is the element.

Some others have no element.

That would give you more than a tingle.

In fact it doesn't.

But there is a reason that wimps call them suicide showers.

It wouldn't bother me using one.

It clearly doesn't with most europeans and chinese either.

I'm just wondering why you don't get a full electric shock

Because the resistance of the water is surprisingly high.

instead of the tingle in the head that people claim to have had from
unearthed ones.

They wouldn't normally be earthed unless it's a shower
in a bath and even then obviously not with an acrylic bath.

If you were stood in your shower, and someone introduced a live conductor
in the water stream above you, you'd get a ****ing big jolt surely?

No you don't, because the resistance of the
water is a lot higher than you might think.

Plenty in europe and china heat water in a cup
by putting a couple of electrodes connected to
the mains active and neutral directly in the water.

That wasn't that uncommon in britain at one time either.

Clearly quite dangerous tho if you grab the electrodes.