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Safety in electric showers
|
|
| M.C.C.R. 2006-03-15, 2:21 pm |
| Dear member:
I have a technical question: I have seen many electric showers
installed in houses, even without grounding system. Why, in an
electric shower, doesn't exist any risk of electric shock to users,
being in direct contact the electricity with the water, and the water
with people?
Would like to know the technical reason.
Thanks,
M.C.C.R.
| |
| Palindr☻me 2006-03-15, 2:21 pm |
| M.C.C.R. wrote:
> Dear member:
>
> I have a technical question: I have seen many electric showers
> installed in houses, even without grounding system. Why, in an
> electric shower, doesn't exist any risk of electric shock to users,
> being in direct contact the electricity with the water, and the water
> with people?
> Would like to know the technical reason.
The most important reason is that the electrical wire that gets hot and
hence heats the water, is surrounded by an electrically insulating
material which is then sealed into an air and water tight metal tube. So
no water gets into contact with the heating wire.
Secondly, pure water is not a very good conductor.
However, it only needs a little bit of other chemicals to make it
conductive enough. So, if you wan't to electrocute the wife by dropping
a mains radio in the bath - buy her some bath salts for her birthday,
first ;)
--
Sue
| |
|
| Can you elaborate on what you mean by an "electric shower"?
It is vastly easier to suggest a mechanism for shock risk in a shower
than to demonstrate the nonexistence of shock risks. Do you have a
particular risk in mind?
Chuck
M.C.C.R. wrote:
> Dear member:
>
> I have a technical question: I have seen many electric showers
> installed in houses, even without grounding system. Why, in an
> electric shower, doesn't exist any risk of electric shock to users,
> being in direct contact the electricity with the water, and the water
> with people?
> Would like to know the technical reason.
> Thanks,
>
> M.C.C.R.
>
| |
| M.C.C.R. 2006-03-15, 5:21 pm |
| Thanks for your reply. With "electric shower", I mean the kind that
are vastly used in Latin America. For example, the famous Lorenzetti
(www.lorenzetti.com.br)
The risk I have in mind, is that a normal day, after turning on the
shower to take a bath (or maybe being one's wife at the shower, as Sue
suggest :-) one can get a very dangerous electric shock. I think it
could be fatal in that case, being naked and surronded by water.
M.C.C.R.
| |
| chuck 2006-03-15, 10:21 pm |
| Thank you for the additional information. I checked the Lorenzetti web
site but didn't learn much.
Normally, the heating element in a water heater is enclosed in a
grounded, metal case. If there is a short from the heating element to
the case, a circuit breaker or fuse should interrupt the circuit
quickly. Assuming, of course, that it has been installed properly.
In terms of safety, it would seem that this system is as safe (or
unsafe) as large tank-type water heaters.
I'm not so sure about the effect of impurities in the water. If the
water's conductivity is very poor, current is going to prefer passing
through the body to going around the body through the water. In salt
water, for example, the body's resistance is so much higher than the
surrounding water that electrocution is much less likely.
Chuck
M.C.C.R. wrote:
> Thanks for your reply. With "electric shower", I mean the kind that
> are vastly used in Latin America. For example, the famous Lorenzetti
> (www.lorenzetti.com.br)
>
> The risk I have in mind, is that a normal day, after turning on the
> shower to take a bath (or maybe being one's wife at the shower, as Sue
> suggest :-) one can get a very dangerous electric shock. I think it
> could be fatal in that case, being naked and surronded by water.
> M.C.C.R.
>
| |
| Beachcomber 2006-03-16, 11:21 am |
| On Thu, 16 Mar 2006 01:53:11 GMT, chuck <nospam@nospam.net> wrote:
>Thank you for the additional information. I checked the Lorenzetti web
>site but didn't learn much.
>
Am I seeing this right? On these Lorenzetti's, up to 220 Volts is
actually brought into the shower head, in the shower stall itself?
I'm comfortable with electric hot water heaters, but I don't want to
be anywhere near 220 Volts when I am naked and dripping wet in the
shower.
Beachcomber
| |
| Palindr☻me 2006-03-16, 12:21 pm |
| Beachcomber wrote:
> On Thu, 16 Mar 2006 01:53:11 GMT, chuck <nospam@nospam.net> wrote:
>
>
>
>
> Am I seeing this right? On these Lorenzetti's, up to 220 Volts is
> actually brought into the shower head, in the shower stall itself?
>
> I'm comfortable with electric hot water heaters, but I don't want to
> be anywhere near 220 Volts when I am naked and dripping wet in the
> shower.
>
Perfectly normal, in the UK at least. Although in the UK it will be
earthed and every metal pipe will be bonded to its earth locally.
The water heater in the shower will typically be 7 -9kW - possibly a bit
much for 110v in the US?
http://www.argos.co.uk/static/Produ...ber/8322481.htm
Until recently, these were commonly a DIY install - with the DIY'er
being left to work out what to earth or not..plus having to lay a
dedicated circuit back to the main house distribution box, add a circuit
breaker, etc..
Personally, I prefer a nice long soak in a bath to a quick shower...
--
Sue
| |
|
| Wait a sec, do I understand the question?
The heating wire is surrounded by water (tap water is not so pure it
doesn't conduct.)
The case is grounded.
The incoming water pipe is grounded, and full of water that is also a
ground conductor.
The drain is grounded.
If there is a loose source of current (water heater or spouse) would it
not follow the easiest path to ground? Which would not include a body
unless the current goes to it first, then to the water.
So I conclude, don't touch electrical items when in the shower, but if
it falls in the water it's not so bad.
RickR
| |
|
| RickR wrote:
> Wait a sec, do I understand the question?
>
> The heating wire is surrounded by water
Probably not if you mean the heating element itself. It would quickly
boil the water off as steam. There may be a ceramic insulator between
the heating element case and the element wire. Something to transfer
heat but not electricity.
(tap water is not so pure it
> doesn't conduct.)
Correct.
> The case is grounded.
Correct.
> The incoming water pipe is grounded, and full of water that is also a
> ground conductor.
Could be. Could be plastic. 240 VAC tank type water heaters in the US do
fine with plastic pipes.
> The drain is grounded.
>
Could be. Could be plastic.
> If there is a loose source of current (water heater or spouse) would it
> not follow the easiest path to ground? Which would not include a body
> unless the current goes to it first, then to the water.
The fault mechanism would most likely be a short from the heating
element to the water. That would probably require that the grounded
metal case be breached, but unless it completely disappeared, it is
difficult to imagine current ignoring that part of the metal case that
is intact and flowing instead through the hole into the water and down
the drain. That would be truly amazing!
>
> So I conclude, don't touch electrical items when in the shower,
Good conclusion.
but if
> it falls in the water it's not so bad.
If by "it" you mean the appliance, and by the water you mean the shower,
I would panic. If it is a bathtub, I would also panic. Most electrical
appliances are nowhere near as safe as a metal-jacketed water heating
element in a properly designed and installed system.
Chuck
>
> RickR
>
| |
| Beachcomber 2006-03-16, 7:21 pm |
|
>Perfectly normal, in the UK at least. Although in the UK it will be
>earthed and every metal pipe will be bonded to its earth locally.
>
>The water heater in the shower will typically be 7 -9kW - possibly a bit
>much for 110v in the US?
>
>http://www.argos.co.uk/static/Produ...ber/8322481.htm
>
>Until recently, these were commonly a DIY install - with the DIY'er
>being left to work out what to earth or not..plus having to lay a
>dedicated circuit back to the main house distribution box, add a circuit
>breaker, etc..
>
.... Perhaps you could answer a few UK bathroom questions for a dumb
American who is only familiar with the American way (i.e. having a
big standing 40-80 gallon tanks of hot water, heated to the max, with
gas or electric, and ready 24 hours per day.)
It sounds inefficient, but it really is not.
What about the hot water faucet for the washbasin or sink? Is that
centrally heated or does it come off the shower heater somehow? Or is
just cold water available for the most part?
Even at 220 volts, every time the shower heater kicks at 9 kiloWatts
or so... That's still a hell of a lot of current... Wouldn't there
be a demand problem say in an apartment complex where everybody turns
on their shower during the morning hours? I would think the lights
would be dimming all over the place.
(Just as an aside... US Electric water heaters are also generally
9000 watts total, but most come with two 4500 watt elements and only
one is switched on at a time)
Beachcomber
| |
| Palindr☻me 2006-03-16, 9:21 pm |
| Beachcomber wrote:
>
>
> ... Perhaps you could answer a few UK bathroom questions for a dumb
> American who is only familiar with the American way (i.e. having a
> big standing 40-80 gallon tanks of hot water, heated to the max, with
> gas or electric, and ready 24 hours per day.)
>
> It sounds inefficient, but it really is not.
>
> What about the hot water faucet for the washbasin or sink? Is that
> centrally heated or does it come off the shower heater somehow? Or is
> just cold water available for the most part?
The shower heater output goes *only* to the shower rose - without any
valves in the way. Flow is controlled by varying the water flow into the
heating tank within the unit.
The following link shows how central heating systems provide hot water
to the normal taps in the house:
http://www.diydoctor.org.uk/projects/boilers.htm
The hot water tank, where fitted, normally has one or two electric
immersion heaters, to heat the water when the central heating system
isn't running. Where the house has electric central heating, one
immersion heater is at the bottom of the tank and is fed from the
cut-price off-peak side of the electric meter, giving a tank full of hot
water, heated overnight. The top heater is fed with full-price
electricity, to make up any shortfall from the overnight heating cycle.
Small electrical heaters, like the shower water heater and also a
kitchen equivalent, are fed via their own dedicated circuits from the
main distribution point. AFAIK,IIRC, my flat was typical and had a 60A
supply. In these days where the house is empty all day, a couple of
these small heaters provides all the hot water needed. So the immersion
heaters are switched off.
I live in the middle of a National Park so have no mains gas. It's quite
large, 7 bedrooms, but has a large (walk-in) fireplace in the drawing
room that I keep a log fire running constantly in the winter. The back
of the fireplace has a cast iron water "boiler"/heat reflector that is
convection linked to produces the hot water for the house. Most older
houses with fireplaces had such a "back boiler" - but real fireplaces
are pretty rare these days. The hot water tank is about 120 gallons. As
I have to manually move the heat reflector to vary the heat that reaches
the boiler, most of the time the water is way, way too hot. Perhaps just
as well it isn't linked to radiators..Mind you, it gives a nice deep,
long bath...
HTH
Sue
>
> Even at 220 volts, every time the shower heater kicks at 9 kiloWatts
> or so... That's still a hell of a lot of current... Wouldn't there
> be a demand problem say in an apartment complex where everybody turns
> on their shower during the morning hours? I would think the lights
> would be dimming all over the place.
>
> (Just as an aside... US Electric water heaters are also generally
> 9000 watts total, but most come with two 4500 watt elements and only
> one is switched on at a time)
>
> Beachcomber
>
| |
| Beachcomber 2006-03-17, 6:21 am |
|
>I live in the middle of a National Park so have no mains gas. It's quite
>large, 7 bedrooms, but has a large (walk-in) fireplace in the drawing
>room that I keep a log fire running constantly in the winter. The back
>of the fireplace has a cast iron water "boiler"/heat reflector that is
>convection linked to produces the hot water for the house. Most older
>houses with fireplaces had such a "back boiler" - but real fireplaces
>are pretty rare these days. The hot water tank is about 120 gallons. As
>I have to manually move the heat reflector to vary the heat that reaches
>the boiler, most of the time the water is way, way too hot. Perhaps just
>as well it isn't linked to radiators..Mind you, it gives a nice deep,
>long bath...
>
Interesting information... It sounds like you UK residents have some
choices in heating systems that we Americans mostly lack although on
the East Coast of the US, one sees more of these combined
heating/domestic hot water boiler systems, mostly oil-fired.
Elsewhere in the US, where natural gas is available, the domestic hot
water and building heating systems are mostly kept separate. There
are some hydronic boiler heating systems in newer construction, but
the gas-forced air furnace is still probably the most common system
installed today.
Time rate (cheap rate) electric service for residential is only
available in certain markets and requires the installation of a
special electric meter (usually at extra cost + a monthly rental fee).
What does a UK person typically pay for in terms of the rate for
electricity?
In the US, it commonly varies from 6 cents (US) to 14 cents per kWh
although some expensive markets (mostly in the Northeast) have
super-expensive rates of up to 20 cents per kwH or so.
Beachcomber
| |
| Palindr☻me 2006-03-17, 11:21 am |
| Beachcomber wrote:
>
>
> Interesting information... It sounds like you UK residents have some
> choices in heating systems that we Americans mostly lack although on
> the East Coast of the US, one sees more of these combined
> heating/domestic hot water boiler systems, mostly oil-fired.
>
> Elsewhere in the US, where natural gas is available, the domestic hot
> water and building heating systems are mostly kept separate. There
> are some hydronic boiler heating systems in newer construction, but
> the gas-forced air furnace is still probably the most common system
> installed today.
>
> Time rate (cheap rate) electric service for residential is only
> available in certain markets and requires the installation of a
> special electric meter (usually at extra cost + a monthly rental fee).
UK:The special meter is installed for free - but the daytime tariff is
higher with a special meter.
>
> What does a UK person typically pay for in terms of the rate for
> electricity?
>
These are the rates for my area from a major supplier - it varies from
place to place and supplier to supplier:
1st 1144 kWhr per quarter : 25.181p (0.439685441 U.S. dollars)
1144- 73268 kwhr per quarter : 13.132p (0.229297852 U.S. dollars)
Over 73268 kWhr per quarter : 2.595p (0.045311295 U.S. dollars )(also
the night rate)
So you would have to use over 2000 USD of electricity a year to move off
the most expensive rate.
You would have to use over 68000 USD of electricity a year to move onto
the cheapest rate - although, if you have a special meter you get 7
hours of cheapest rate each night, say between 11pm and 6am.
> In the US, it commonly varies from 6 cents (US) to 14 cents per kWh
> although some expensive markets (mostly in the Northeast) have
> super-expensive rates of up to 20 cents per kwH or so.
I think I have just re-defined "super-expensive" for you ;)
--
Sue
| |
|
| >The fault mechanism would most likely be a short from the heating
>element to the water. That would probably require that the grounded
>metal case be breached, but unless it completely disappeared, it is
>difficult to imagine current ignoring that part of the metal case that
>is intact and flowing instead through the hole into the water and down
>the drain. That would be truly amazing!
This is my point.
Where does a body in tub become part of the circuit? Granted the drain
could be plastic and the tub fiberglass so the body would receive a
voltage differential as the AC cycles, but no current to speak of. Is
that enough to kill?
| |
| Beachcomber 2006-03-17, 9:21 pm |
| On 17 Mar 2006 16:09:47 -0800, "RickR" <info@luminousviews.com> wrote:
>
>This is my point.
>Where does a body in tub become part of the circuit? Granted the drain
>could be plastic and the tub fiberglass so the body would receive a
>voltage differential as the AC cycles, but no current to speak of. Is
>that enough to kill?
>
It doesn't take much for a potential difference to find a conductive
path to ground, especially at 240 volts. I'm just surprised that the
UK codes apparently allow this level of voltage in a wet environment
like a shower. I wonder what the statistics are for people
electrocuted or injured in UK shower/electrical accidents each year?
Those bonding rules for all metal in the bathroom environment are
pretty strict.
I once got the shock of a lifetime by standing barefoot on a damp (not
wet) tile floor and touching a defective 120V. lamp socket. It was
the fact the the current was passing through my whole body (not just
my hand) that made it difficult to let go. It was very, very painful.
BTW, Prior to this, I would have never guessed that a damp tile floor
would carry a current to ground.
Beachcomber
| |
|
| You've posed a very interesting question. Definitely not the sort of
thing we care to experiment with.
With a fiberglass tub and plastic drain, a powered appliance like a hair
dryer dropped into the water most probably would not trip a breaker. If
the hot wires were spaced an inch apart in the appliance, there would be
a strong field between those points and the field would curve outward
beyond the one inch. But would the field be strong enough at six inches
to even be felt by a human? Would it be lethal? My guess, and it is
barely more than that, is that it would not. Also, it would depend on
where it landed in the water. Most of us would react by grabbing the
appliance to toss it out of the tub, which would probably be a bad move.
I wonder what the safe thing to do might be. Pull the cord from the
outlet? Lift the appliance out of the water by the dry part of the cord.
Yell for help? Interesting.
With a grounded metal drain in the tub or maybe with a grounded metal
tub, it's a no-brainer, of course. Even if the water is distilled and
there is effectively no current through the water, the drain and the hot
wire create an electric field in the water. The body placed in that
field experiences a voltage differential between head and foot, as you
suggested, which, given the resistance of the body, is enough to cause a
lethal current (generally more than 5 milliamperes) to flow through the
body.
I have left out that there will be two fields: one from the hot wire to
the neutral in the appliance, and the other from the hot wire to the
grounded drain. The latter field would probably be a lot weaker.
Chuck
RickR wrote:
>
>
> This is my point.
> Where does a body in tub become part of the circuit? Granted the drain
> could be plastic and the tub fiberglass so the body would receive a
> voltage differential as the AC cycles, but no current to speak of. Is
> that enough to kill?
>
| |
| Andrew Gabriel 2006-03-18, 7:21 am |
| In article <441b51b5.3695781@newsgroups.comcast.net>,
not_real@xxx.yyy (Beachcomber) writes:
>
> It doesn't take much for a potential difference to find a conductive
> path to ground, especially at 240 volts. I'm just surprised that the
> UK codes apparently allow this level of voltage in a wet environment
> like a shower.
The shower units are designed for such use, obviously.
Such units are used all over the 220-240V world.
In the UK, they vary between 7kW and 10.5kW. In some
other European countries, higher power ones are used.
> I wonder what the statistics are for people
> electrocuted or injured in UK shower/electrical accidents each year?
I was following the stats for a while, and there was around one
every 5 years. Last one, cause is unknown because of gross incompetence
in the investigation. (The electrical company who fitted it were
initially asked to investigate, and found nothing wrong, a result
which is clearly bogus as the shower had just killed someone. Any
further investigation after the company had taken the installation
to pieces was rather pointless. Almost certainly, the bonding
had been missing or faulty as the accident would have been impossible
with it.)
Well, there was a more recent one too. A guy doing a full house refurb
decided to take a shower. There was no electricity in the house at
the current state of refurb, so he used an extension cord from a
neighbour to power the shower. As far as investigators could tell,
he must have been holding the shower heater unit whilst showering,
which is supposed to be fixed to the wall, because there was no
sign that it ever had been. In the UK groups where this issue came
up, the expression "Darwin Award" was liberally used.
> Those bonding rules for all metal in the bathroom environment are
> pretty strict.
Yep. It pretty much means regardless of any electrical fault, there's
almost no way you can be electrocuted because there can't be any
potential differences between exposed metalwork in the bathroom.
It's a scheme which seems to have worked very well for best part of
50 years.
--
Andrew Gabriel
| |
| Andrew Gabriel 2006-03-18, 8:21 am |
| In article <121lil0hsaa2e1c@corp.supernews.com>,
=?UTF-8?B?UGFsaW5kcuKYu21l?= <me9@privacy.net> writes:
>
> These are the rates for my area from a major supplier - it varies from
> place to place and supplier to supplier:
>
> 1st 1144 kWhr per quarter : 25.181p (0.439685441 U.S. dollars)
>
> 1144- 73268 kwhr per quarter : 13.132p (0.229297852 U.S. dollars)
>
> Over 73268 kWhr per quarter : 2.595p (0.045311295 U.S. dollars )(also
> the night rate)
You are paying a very expensive day rate because you have different
day/night tarifs. In comparison, I don't, and my continuous rate is
7.34p/kWhr (0.128 USD) for first 727kWh/quarter
6.96p/kWhr (0.121 USD) after first 727kWh/quarter
There is another higher price break, but I didn't reach it so it
doesn't say what it is on my bill.
If I shopped around, I could significantly reduce these prices.
--
Andrew Gabriel
| |
| Palindr☻me 2006-03-18, 9:21 am |
| Andrew Gabriel wrote:
> In article <121lil0hsaa2e1c@corp.supernews.com>,
> =?UTF-8?B?UGFsaW5kcuKYu21l?= <me9@privacy.net> writes:
>
>
>
> You are paying a very expensive day rate because you have different
> day/night tarifs. In comparison, I don't, and my continuous rate is
>
> 7.34p/kWhr (0.128 USD) for first 727kWh/quarter
> 6.96p/kWhr (0.121 USD) after first 727kWh/quarter
>
> There is another higher price break, but I didn't reach it so it
> doesn't say what it is on my bill.
>
> If I shopped around, I could significantly reduce these prices.
>
Note the "from a major supplier" - actually British Gas*.
LOL, I didn't mention the company name as it might be a little confusing
for some of the readers that we in the UK buy our electric from "British
Gas".
I picked it to illustrate the off-peak rate that was being discussed..
UK electrickery seems to be more expensive than the US equivalent
though. But the price difference looks a lot closer than the difference
between what we pay for vehicle fuel..
*I don't actually pay it as I am on a single rate tariff, as you are,
from a different supplier.
--
Sue
| |
| Beachcomber 2006-03-18, 6:21 pm |
|
>
>These are the rates for my area from a major supplier - it varies from
>place to place and supplier to supplier:
>
>1st 1144 kWhr per quarter : 25.181p (0.439685441 U.S. dollars)
>
>1144- 73268 kwhr per quarter : 13.132p (0.229297852 U.S. dollars)
>
>Over 73268 kWhr per quarter : 2.595p (0.045311295 U.S. dollars )(also
>the night rate)
>
>So you would have to use over 2000 USD of electricity a year to move off
>the most expensive rate.
>
>You would have to use over 68000 USD of electricity a year to move onto
>the cheapest rate - although, if you have a special meter you get 7
>hours of cheapest rate each night, say between 11pm and 6am.
>
>
>
>I think I have just re-defined "super-expensive" for you ;)
>
>--
>Sue
>
Sue:
Holy cow! That is expensive... something like (US) $0.70 - $0.75 per
10 minute shower at the day rate. On the other hand, it is
surprisingly cheap at the night rate. That is quite a differential.
Thanks for the info...
Beachcomber
| |
|
| Too much TV!
Someone tosses a hairdryer into the tub and after the sparks settle the
murder story can proceed. My (less than Phd) electrical knowledge says
bunk!
chuck wrote:
> You've posed a very interesting question. Definitely not the sort of
> thing we care to experiment with.
>
> With a fiberglass tub and plastic drain, a powered appliance like a hair
> dryer dropped into the water most probably would not trip a breaker. If
> the hot wires were spaced an inch apart in the appliance, there would be
> a strong field between those points and the field would curve outward
> beyond the one inch. But would the field be strong enough at six inches
> to even be felt by a human? Would it be lethal? My guess, and it is
> barely more than that, is that it would not. Also, it would depend on
> where it landed in the water. Most of us would react by grabbing the
> appliance to toss it out of the tub, which would probably be a bad move.
> I wonder what the safe thing to do might be. Pull the cord from the
> outlet? Lift the appliance out of the water by the dry part of the cord.
> Yell for help? Interesting.
Yelling sounds good to me. I probably would anyway!! I would recommend
touching only things that are in water with you.
If both hot & neutral are in the water I suspect that the
breaker/fuse/GFIC would trip. After all you have an unstricted flow
between conductors until the tub boils dry. Something has to give.
What about an unbalanced condition? A loose hot charges the water
you're in. No ground or current flow until you touch something.
>
> With a grounded metal drain in the tub or maybe with a grounded metal
> tub, it's a no-brainer, of course. Even if the water is distilled and
> there is effectively no current through the water, the drain and the hot
> wire create an electric field in the water. The body placed in that
> field experiences a voltage differential between head and foot, as you
> suggested, which, given the resistance of the body, is enough to cause a
> lethal current (generally more than 5 milliamperes) to flow through the
> body.
>
> I have left out that there will be two fields: one from the hot wire to
> the neutral in the appliance, and the other from the hot wire to the
> grounded drain. The latter field would probably be a lot weaker.
>
> Chuck
I guess the worst case scenario is a hot case at the showerhead and a
grounded tub/drain/pool. The water in the shower would ground
"upstream" but if you touched the hot case with your feet in pool -
bye!
RickR
| |
| chuck 2006-03-27, 11:21 am |
| RickR wrote:
> Too much TV!
> Someone tosses a hairdryer into the tub and after the sparks settle the
> murder story can proceed. My (less than Phd) electrical knowledge says
> bunk!
>
Well Rick, I have an open mind, but it is not easily persuaded by
derision. How about some analysis?
> chuck wrote:
>
>
>
> Yelling sounds good to me. I probably would anyway!! I would recommend
> touching only things that are in water with you.
Do you understand what an electrical field is? Please see below.
>
> If both hot & neutral are in the water I suspect that the
> breaker/fuse/GFIC would trip. After all you have an unstricted flow
> between conductors until the tub boils dry. Something has to give.
>
Do you believe 15 amps or more will flow through tap water under the
scenario described? What do you believe the conductivity of the
hot-to-neutral tap is? I'm wondering which of us has been watching too
much TV!
> What about an unbalanced condition? A loose hot charges the water
> you're in. No ground or current flow until you touch something.
>
Please explain.
>
>
>
> I guess the worst case scenario is a hot case at the showerhead and a
> grounded tub/drain/pool. The water in the shower would ground
> "upstream" but if you touched the hot case with your feet in pool -
> bye!
>
Sorry, Rick. I don't follow your argument here. The general rule is
this: if a person is placed in an electrical field, such that the
potential difference across critical parts of the body causes a current
in excess of x milliamperes to flow, death will ensue. Creating such a
field with 120 VAC in salt water is somewhat difficult. In fresh water,
it is a piece of cake. Now think about the ways an electric field can be
generated in bath water and you're home free.
Chuck
> RickR
>
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