BS: Shock Risk from AA Batteries/Water?

Subject: BS: Shock Risk from AA Batteries/Water?
From: wysiwyg
Date: 10 Jan 06 - 03:47 PM

LOL-- I KNOW this is a dumb question, but I was PROGRAMMED as a young child: NEVER mix electricity and water.

If the battery-operated MP3 player is at poolside (well wrapped in plastic of course), and the headphones are on my head when I jog in the pool-- am I risking harming anything except, maybe, the MP3 player?

LOL-- here's a chance for unfriendlies to give me fatal advice! :~)

~Susan

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Clinton Hammond
Date: 10 Jan 06 - 03:49 PM

No risk, except you stand to RUIN your mp3 player....   

get wireless headphones.... then you'll just run the risk of ruining those....

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: wysiwyg
Date: 10 Jan 06 - 03:52 PM

Wireless headphones? Tell me more.

(It's a CHEAP MP3 player, like $40.)

~S~

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Rapparee
Date: 10 Jan 06 - 03:56 PM

I dunno about double As (L6s to some), but I learned many years ago not to see if a 9 volt battery was dead by touching both contacts with my tongue.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Metchosin
Date: 10 Jan 06 - 04:41 PM

Actually I learned that more recently Rapaire. I got sort of used to licking the top of AAs to see if I could squeeze a little more life out of them and one day, absent mindedly, did the same thing to a 9V...duh.....LOL

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: wysiwyg
Date: 10 Jan 06 - 04:59 PM

So-- does it matter how many AAs? Like, 4?

~S~

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: GUEST
Date: 10 Jan 06 - 05:08 PM

It's the volts that jolt and the mills (miliamps) that kill. One of your batteries could supply sufficient current but they would not be able to force it through the resistance of your body.

You are quite safe with 4 AAs.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Ebbie
Date: 10 Jan 06 - 05:08 PM

That's an interesting question, Susan. I look forward to the definitive answer. It even bothers me to answer the phone when I'm in the tub- and yet I've been assured that the risk is minimal.

I should do what one of my sisters did once: She was curious as to whether a rabbit would bite so she stuck her younger sister's finger into the cage. The rabbit did.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: wysiwyg
Date: 10 Jan 06 - 05:12 PM

OK, Eb, do you want to be my little sister? :~)

~S~

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Fullerton
Date: 10 Jan 06 - 07:11 PM

A 240v mains shock via water is horrible - horrible horrible.
(Shudders at memory)

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: bobad
Date: 10 Jan 06 - 08:11 PM

It ain't the volts, it's the amps - I think.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: leftydee
Date: 10 Jan 06 - 10:15 PM

It takes roughly 50 volts to pierce your skin. AA batteries are 1 1/2 volts so..... if you put 35 to 40 of these little guys in series (end to end) you could get a little poke. I did hear of a guy killing himself with a 9volt battery by wiring a pin to each terminal and then sticking himself in each index finger. I suspect that this is a crock but ........ Essentially, batteries are safe. When touching a 9 volt to your tongue you don't really feel a shock but , if the battery is good, it will taste sour. Be careful with 9volt batteries because you can ignite your pants if you put a good battery in a pocket with some change. I've done it.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: wysiwyg
Date: 10 Jan 06 - 10:24 PM

Thanks, leftydee!

~S~

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Metchosin
Date: 10 Jan 06 - 10:34 PM

Waddya mean you don't get a shock! I bridged the terminals of a 9V with my tongue and I certainly got more than a sour taste. Smartened me up very quickly, it did.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Rapparee
Date: 10 Jan 06 - 10:57 PM

You bet yer booties it gives you a shock! It was LOTS more than a sour taste. Try it and see.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Bee-dubya-ell
Date: 10 Jan 06 - 10:58 PM

I dunno nothin' about batteries, but I do wanna know why Wysi jogs in the pool. Most people jog on a track and swim in a pool.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Amos
Date: 10 Jan 06 - 11:08 PM

The lethality (as mentioned above) is from the current, not the voltage.

IF I recall correctly 20 millimps is lethal, but I could be misremembering.

If the 4 AAs discharge all at once into the pool, the water will presumably conduct the current along the path of least resistance, probably down the drain pipe or fill pipe. If you are floating in the pool, you probably won't feel it.

They have a combined total capacity of 6 volts, so to produce a current of .002 Amps, they would have to be all at once directed a long a path of 3,000 ohms, if my figures are right.
The body ranges between around 4K and 20K ohms.

A

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Bobert
Date: 10 Jan 06 - 11:09 PM

Well, me and the Wes Ginny Slide Rule once spent an all nighter on exactly this question... My couzin Rufus was going thru some tough times with Rether May and he asked me if he could kill himself with his flashligh batteries... Heck, he offered to eat 'um, that's how bad the boy was.... Hey, it was Christmas... What can you say...

So me and WGSR worked thru the night and when mornin' come 'round we hadn't figgued out no way for the poor boy to do the deed with just the batteries.... Yeah, eatin' um wouldn't have done the trick but we did offer him, Plan B... Hey, it was Christmas, gol danged it!!!

We figgued that if Rufe put the batteries back into his Coleman flashlight that it would have sufficient weight for Rufus to beat himself to death with it...

What we didn't factor in was alcohol... Now, alcohol can be man's worse enemy or best friend... Kinda like a dog... So here it was three days before Christmas and I get a call from Retha May and she's crying and all and says that Rufus is out in the Chevette with a bunch of blood on his face.... Hey whats a guy gonna do???

So I go on over and, sho nuff, Rufus got some blood on his face but most from a bloody nose he got when he passed out from the Iron City and hit the steering wheel... Well, I woke him up, took him back up the half a double-wide and me and Retha May cleaned the boy up and tucked him into the sofa...

He looked so innocent there...

Sniff, that was the best Christmas...

Ahhhh, what was the question????

Bobert

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Amos
Date: 10 Jan 06 - 11:12 PM

By contrast with your 6 combined volts, the average house current is 110V, 60Hz alternating current. If you grab ahold of some, depending on how well you are grounded (standing in water) or not grounded (wearing rubber soles) the current may pass through you seeking its path to ground because you represent the path of least resistance.

Under these conditions with 60Hz AC, the following values apply:

1 mA        Barely perceptible
16 mA        Maximum current an average man can grasp and "let go"
20 mA        Paralysis of respiratory muscles
100 mA        Ventricular fibrillation threshold
2 Amps        Cardiac standstill and internal organ damage
15/20 Amps        Common fuse or breaker opens circuit*

A

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: JohnInKansas
Date: 11 Jan 06 - 01:42 AM

AA batteries may vary from about 1.2 to 1.5+ volts, depending on the battery type. Four AA batteries would usually be in series, giving not more than about 6 volts at the battery pack. In that configuration, there is little danger that you'd get a "shock" you could feel directly from the batteries.

As noted, a 7.5 v battery is sufficient to produce an acid taste if you place your tongue on the terminals, but should be harmless except to the extremely sensitive. Those who get an objectionable effect should try to use their tongue more in excercises that will strengthen and toughen it, instead of in mindless prattle that does the tongue no real good. (What you've recently had in your mouth can have a significant effect on your sensation.)

As it's the earpiece that's actually connected to the body, it matters less what the batteries can do. The "player" can convert battery voltage to whatever is needed elsewhere in the circuit, although in cheap transistorised devices the battery voltage normally is the highest voltage needed anywhere in the circuit. Assuming 4 ohms or less for your earpiece speaker, application of sufficient voltage to destroy your hearing should not cause a "shock" hazard, so you won't die from listening to it until you walk in front of the taxi you didn't hear honking at you.

Telephones present a number of differing possibilities. A "landline" phone, with the handpiece connected to the phone base, can present 35, 50, or 70 volts in the "ring" and "busy signal" circuit. In dry conditions, it's possible to get a nasty shock from these voltages, and especially in wet places, in some bizarre circumstances, these voltages are sufficient to cause fatal effects.

RF phone handsets, where there is no cord, usually (in the US) have a battery that's not more than 12 volts, but may have an oscillator to step the voltage up to something higher for the required radio signals. Since any higher voltage is between points inside the handset, the voltages are floated with respect to the ouside world's "ground voltage" so most likely if you dunk the handset it will just short-circuit internally, without producing a shock to the user/occupant. If it's still going when you pick it up out of the water and stick it on your ear, you could get a shock sensation, but at the GHz frequencies common the current is unlikely (not impossible) for the currents to penetrate to where organic damage can occur.

Quoting rules about "this voltage/current will kill you and that voltage/current won't" can be very misleading, since the current path has a lot more to do with the organic damage than simply that there is a current. Shuffling your feet on the carpet and touching the radiator is generally quite safe, since the charge that's built up is on the surface of your body, and the discharge is across skin surfaces. Shuffling your feet on the carpet and touching someone else who's touching the radiator can - in very rare instances - be harmful to the person touched, since the same currents, applied at the single point of contact, could follow internal body paths.

Stepping off an airplane wing that's not grounded on landing has been lethal to many persons. Jumping off an airplane wing so that no simultaneous contact between airplane and ground happens at the same time has rarely been lethal, but can be very unpleasant and does have some very real potential for harm. (Voltages of 600 V and higher - to as much as 1500+ V - due to inflight static buildup are common.)

The bottom line on the cheap 4 x AA battery powered audio device is that it's unlikely to pose an electrical hazard in or around a pool, but that environment is very hard on devices of this kind. With anything electrical, the bizarre circumstance that disproves any rule should be anticipated.

John

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Clinton Hammond
Date: 11 Jan 06 - 02:24 AM

If ya don't wanna ruin your MP3 player, keep it away from the pool

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: s&r
Date: 11 Jan 06 - 03:19 AM

I should point out that jumping from an airplane wing is not generally fatal *after landing*.

Stu

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Paul Burke
Date: 11 Jan 06 - 03:47 AM

Amos, if you short a battery in a pool, the current will be conducted through the water by the shortest path BETWEEN THE BATTERY TERMINALS. So (alkaline) batteries are safe to everyone except themselves in water (a NiCad or lithium battery could explode, but there's still no danger from shock).

Mains and water must not be mixed.

Mains in the UK is usually fitted these days with an RCCB- this trips out if any leakage to earth is detected (i.e. any current out of the main circuit), normally at 30mA. This gives you an unpleasant jolt (I've experienced it several times), but no lasting ill effects, except upon the Immortal Soul as a result of the cussing that ensues.

The lethal effect of electric shock depends on the current and its duration. Although a small current can lead to cardiac disturbance, it usually doesn't unless sustained. Usually the heart recovers immediately.

In Europe, voltages below 50V are considered "safe" as far as shock is concerned (though you can still get burns from these voltages). Above that voltage, precautions as detailed in the Low Voltage Directive must be observed.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Metchosin
Date: 11 Jan 06 - 04:04 AM

I have often deliberately tested the horseÕs electric fence with a green blade of grass to see if it was on and I have, on occasion, accidentally zapped myself on the leg of the same fence a few times and I also have some vague recollection, that once, after a bit to drink, I bushed my bare backside on an electric bear fence while squatting to take a pee.

While each provided a jolt of varying degrees, none was quite as memorable or disconcerting as zapping my tongue with a 9 volt battery. Could it be that Rapaire and I have saltier tongues than others? Or just that we are the only ones whoÕs knowledge is practical rather than theoretical, when it comes to doing dumb things?

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Amos
Date: 11 Jan 06 - 04:25 AM

A high-resistance backside, perhaps...


A

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Metchosin
Date: 11 Jan 06 - 04:29 AM

LOL....perhaps.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: GUEST
Date: 11 Jan 06 - 04:38 AM

Try touching the electric fence with your tongue (don't do it!) and the 9v battery on your bare bum for comparison.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: robomatic
Date: 11 Jan 06 - 06:33 AM

When lightweight lithium batteries first came out, they could produce noxious 'gas' when overheated, as a camping instructor with a headlamp discovered when his battery vented under his parka. don't know if this is still a 'potential' (heh-heh) problem.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Liz the Squeak
Date: 11 Jan 06 - 06:46 AM

Metchosin - I have it on good authority that nothing is more painful than the jolt suffered by a male member brushing against an electric fence whilst peeing..... I cannot compare, not having a) the equipment to pee standing, b) peed anywhere near an electric fence or c) the mental incapacity to stick any part of my body on live electrical wires. Suffice it to say, it was a very long time before he was interested in gathering blackberries.

LTS












And yes.. it was even longer before I stopped laughing. Ain't I a stinker?!

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: GUEST,Dazbo
Date: 11 Jan 06 - 07:27 AM

Interesting discussion as it brings back a limited amount of my electrical engineering courses.

What happens to you if you are floating in water (a swimming pool for example or a big bath) and someone chucks in an electric fire or hair drier (see Hollywood) connected to the mains? Surely you would not be the least resistant part of any resultant circuit so should be fairly safe. Is this correct? (And no, I'm not willing to test it under any circumstances!!!)

Also, having recently watched What Women Want on the TV over the holidays Mel Gibson's character is shown drying his hair with a hair drier and falling into the bath gets a shock (fair enough as he is obviously part of the circuit mains, drier, Gibson, water, bath to earth). However do American bathrooms have mains sockets? In the UK and in Europe, the only sockets we are legally allowed in bathrooms are 110V (rather than the 220V mains) an are for electic shavers and there is no connection with the mains. As I understand it basically the electric current is induced so there is no connection between earth and the electric shaver.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: JohnInKansas
Date: 11 Jan 06 - 07:49 AM

s&r -

I rather thought that the lead sentence:

Stepping off an airplane wing that's not grounded on landing

would be assumed to apply to what followed immediately thereafter; however I should have applied the adage that "nothing's stupid proof, 'cause stupid people are too damned clever."

The biggest hazard encountered with Lithium batteries is their unpredictable habit of setting things on fire. And it's not just "when they first came out," as several laptop makers, among others, have had recent Li battery recalls. Lithium reacts vigorously with water, including humidity in the air. Any moisture encapsulated in a battery during manufacture (a manufacturing defect), and/or any leakage of the battery case can cause problems.

It's also been suggested that Lithium oxide produced by battery leakage could be a problem in enclosed spaces, since it's known to be "mood affecting" and in high doses can have unpredictable effects. My own "professional" requests for comment on this subject went unanswered a few years back; but the battery makers' failure to respond persuaded "management" to not use them in at least one commercial airplane system (that I know of) where they were originally included by the designer.

John

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Rapparee
Date: 11 Jan 06 - 09:21 AM

If I tossed a lithim battery into heavy water, could I get lithium VI deutride? Maybe I could puncture the case with my pocketknife, huh?

Sure would like some lithium VI deutride. I'd use it to make a fusion...reactor.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Paul Burke
Date: 11 Jan 06 - 09:25 AM

No, you'd need to make the lilithium react with deuteronomy to get that. But if you can get a funeral reactor going, maybe there's some use for the Bible...

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: GUEST,Bill the sound
Date: 11 Jan 06 - 10:35 AM

Yes AA batteries could give you a nasty shock-but-You'd need ahell of alot or them in series(electrical term)

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Peace
Date: 11 Jan 06 - 10:36 AM

If you have over a thousand wired, be very careful.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Amos
Date: 11 Jan 06 - 10:41 AM

Dazbo, all US mains are 110V 60Hz; UK mains are generally 220V 50Hz. US houses have outlets all over the house including the bathroom and kitchen. Modern ones use Ground Fault Circuit Interrupters for outlets near sinks, though older houses do not.

US houses do often contain 220V stoves, heaters, and the like but they are powered by ganging the 110-volt circuit.

A

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: wysiwyg
Date: 11 Jan 06 - 11:22 AM

Peace, I have "wired" thousands in my lifetime, but not--thank God! -- in series. :~)

~Susan

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: GUEST
Date: 11 Jan 06 - 11:55 AM

WYSYWIG, you will have wired thousands of batteries in series, far more than you will have wired in parallel. Just not all at once.

Amos. Dazbo is wrong, at least for the UK See here.

Any electrical work in bathrooms or kitchens in the UK comes under the part P.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: wysiwyg
Date: 11 Jan 06 - 12:19 PM

Warn't talking about no batteries...

~S~

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Metchosin
Date: 11 Jan 06 - 02:26 PM

LTS,   I don't think on that occasion it was so much inate mental incapacity as the high octane of what I had consumed, that clouded my judgement about exactly where to put my bum......and nah, you're not a stinker, I doubled over once when a gentlemen judged his inseam to be longer than the height of the electric wire. I think I eventually apologized for laughing.

Guest, no fear, I do some very dumb things, but I'm not a deliberate masochist.

Although, if I suck a lithium battery will it help counteract my manic reaction to fire to my mouth?

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: JohnInKansas
Date: 11 Jan 06 - 05:07 PM

Rapaire -

Puncturing a Lithium battery with a pocket knife is definitely one of those "don't try this at home" things not to do. Heat, smoke, noxious vapors, and chemical burns are attendant risks.

At least one of the several "Anarchist Cookbooks" touts Lithium as a proper catalyst for converting pseudoephidrine to methamphetamine, and gives detailed instructions for how to open lithium batteries to extract the lithium. Aside from mostly unworkable reactions throughout the book, it is obvious that the author either has never seen the inside of a lithium battery and has no comprehension of what one actually contains, - or is dead.

John

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: robomatic
Date: 11 Jan 06 - 10:54 PM

electricity is very dangerous in water, as people used to find out in lighted swimming pools prior to the invention of GFCI (Ground Fault Circuit Interrupter) circuits and devices. One of my friends was witness to the research, which he tells me included throwing dogs into pools with a known leaky circuit in order to tell how many milliamps were dangerous. He wouldn't volunteer if this research was fatal to any canines.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: GUEST,Dazbo
Date: 12 Jan 06 - 04:31 AM

Guest - you're right of course that in the UK we do have such things as electric showers, ventilation etc. I wasn't clear about what I was on about: I meant mains sockets for hair driers and other electrical equipment not permanently connected to the electric supply.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: The Fooles Troupe
Date: 12 Jan 06 - 04:34 AM

"Stepping off an airplane wing that's not grounded on landing"

Were a wing grounded on landing, then serious problems would result.

My dad was in the RAAF in WWII.

:P

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: JohnInKansas
Date: 12 Jan 06 - 05:29 AM

Ok Foolestroupe.

With nearly 40 years experience writing specifications and purchase contracts for US military and industrial R&D and procurement, if you really want me to be specific, precise, and unambiguous it's certainly possible; but it will certainly interfere with maintaining my reputation for brevity and wit, and you won't really like it all that much.

John

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: The Walrus
Date: 12 Jan 06 - 06:23 AM

If you want to try something dangerous with batteries, try pushing a 9V battery into wire wool - but make sure it's on a fire proof surface.
Actually, it's a handy way to start a fire if you are out camping/ fishing etc. (but remember to keep the bits in different places).

W

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Rapparee
Date: 12 Jan 06 - 09:21 AM

Walrus, I actually had a friend set his pants on fire that way. He wasn't hurt, but it sure gave everyone at the picnic a good laugh.

4-O steel wool is a very good tinder for fire starting, and it generally has a thin coat of oil on it as well. Be careful with it.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Liz the Squeak
Date: 12 Jan 06 - 09:38 AM

I think the shock risk depends entirely where the battery is inserted..... and who else is watching.

LTS

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Keith A of Hertford
Date: 12 Jan 06 - 09:44 AM

Re peeing and shocking, bodily contact not necessary, the stream will conduct nicely. Electrified railway lines often prove fatal in this way.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Amos
Date: 12 Jan 06 - 10:05 AM

Dazbo,

It's hard for me, as a Yank, to imagine mains sockets not permanently connected to the electrical supply, except for those which have built-in circuit interrupters which trigger on ground faults to prevent accidents near sinks.

Or, switchable outlets which are controlled by a wall switch.

What do such beasts look like over there?

A

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: GUEST
Date: 12 Jan 06 - 12:27 PM

Amos, the sockets are a fixed part of the wiring/installation. Dazbo was reffering to portable appliances that may be plugged into such sockets.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: GUEST
Date: 12 Jan 06 - 12:31 PM

try here for some of our standard switches and sockets.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: leftydee
Date: 12 Jan 06 - 12:47 PM

GFIs became the law of the land about 20 years ago in the USA thru the NEC. There are lots of unprotected sockets out there. Regular circuit breakers trip if overloaded or shorted but offer no protection from ground faults or most electrocutions. GFIs are essentially sensors that look for imbalances between the line (power) and the load (neutral). When there is an imbalance,like me getting zapped between my toaster and the faucet, the line shows power out but the load sees nothing. Hence , we get a tripped GFI. This can happen also if a person gets between the load and ground. It will not protect you from getting directly in line between line and load because it sees no imbalance.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: GUEST
Date: 12 Jan 06 - 02:01 PM

GFI is like what we call an RCD in the UK then?

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Rapparee
Date: 12 Jan 06 - 02:47 PM

When we bought our house there were NO ground fault interuptor circuits. None. Not near sinks, not outside, not none nowhere.

This has been remedied. We have this thing about being electrocuted....

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Liz the Squeak
Date: 12 Jan 06 - 05:46 PM

I used to live in a house where there was a socket immediately behind the taps of the kitchen sink. Because of the layout of the room, it was the only place you could plug the washing machine in. If you did, you had to be really careful not to touch the stainless steel sink, or anything other than the plastic tops of the taps or else you'd get a zap.

This sort of placement of sockets is deeply frowned upon by electricians (and safety officer) but was put in in the days before home wiring had to be inspected.

I took my washing elsewhere.

LTS

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Rapparee
Date: 12 Jan 06 - 06:59 PM

On-off switch for the light above the electric stove USED to be on the wall behind the stove.

Something about reaching over hot burners and boiling pots and kettles....

It's now on the front of the stove.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Amos
Date: 12 Jan 06 - 08:59 PM

Anyway, for those of you who may some day need to think about real current or real power:

VOLTAGE = CURRENT*RESISTANCE (V=IR)

POWER=CURRENT*CURRENT*RESISTANCE=VOLTAGE*RESISTANCE (P=VR or I^2R)
RESISTANCE=VOLTAGE/CURRENT (R=V/I)
CURRENT=VOLTAGE/RESISTANCE (I=V/R)

V is expressed in VOLT
RESISTANCE is expressed in OHMS
CURRENT is expressed in AMPS
POWER is expressed in WATTS

And that's about it. I think....

Editorial review always welcome.


A

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: The Fooles Troupe
Date: 12 Jan 06 - 11:50 PM

Well, Amos, you are right for DC circuits, but with AC, you need to consider the Power Factor...

:-P

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Amos
Date: 13 Jan 06 - 12:24 AM

Foolestroue is referring to the fact taht in alternating current, which goes one way and then the other repeatedly, the point where the voltage peaks and falls and reverses on a sine curve may be out of phase where the point where the current follows ITS sine curve. They go out of phase which cause a discrepancy between the current level seen as in phase with voltage, and the current level where it peaks out of phase with voltage. The ratio of "in phase" current to total current is called the power factor.

Power Factor is the ratio of watts (W) to voltamperes (VA).

But since we were talking about batteries, which are simple direct-current devices, power factor doesn't enter into it.

A

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: JohnInKansas
Date: 13 Jan 06 - 12:28 AM

Amos -

You got the first one right:

V = I*R

Second one half right:

P = V*I = I²*R

But the second part of the second one requires the substitution:

I = V/R

to become

P = V²/R

Foolestroupe -

If you use the RMS voltage and RMS current, simple AC circuit solutions will be okay. In more complex circuits (with lead/lag phase relationships) you can get more complicated. In circuits with multiple frequencies and phase shifts, it can get significantly more complicated, so you use Maxwell's equations instead of Ohm's.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: Amos
Date: 13 Jan 06 - 01:03 AM

Damn, I hate it when that happens. Comes from typing faster than my brain is working....


A

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: JohnInKansas
Date: 13 Jan 06 - 02:19 AM

Amos -

I'm not a really fast *typist, but I can safely brag that I make as many misteakes as anynoe in a given time span.

(*compared to a couple of real pros I've known who could top 1800 cpm for l-o-o-o-o-ng stretches.)

John

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: The Fooles Troupe
Date: 13 Jan 06 - 06:42 AM

"But since we were talking about batteries, which are simple direct-current devices, power factor doesn't enter into it."

Ah - but that would only be for a steady state current - at the instant of making and breaking the contact, the current is changing, thus the natural (though very low) capacitance, and inductance of the human body will affect the calculation...







See - I can BS with the best of them... truly a little knowledge is a dangerous thing in the hands of a fool...

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: s&r
Date: 13 Jan 06 - 07:16 AM

don't lose your marbles..


Stu

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: wysiwyg
Date: 13 Jan 06 - 08:12 AM

But I need to know-- will it cause an anomaly in the space-time continuum?????

~S~

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: GUEST,Dazbo
Date: 13 Jan 06 - 09:40 AM

So to clarify then (I hope!)

In the US it is common to have sockets in the bathroom wall into which you can plug (for example) a hair drier and sit on the edge of the bath drying your hair. This socket is electrically connected to the mains supply and some protection is offered by the use of a GFI (an RCD in the UK?) hopefully installed and working properly.

Whereas in the UK the only socket you are allowed in the bathroom is for electic shavers and this socket is not electrically connected (by wires) to the mains power supply and is not protected by a GFI (or RCD)

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: GUEST, Topsie
Date: 13 Jan 06 - 11:23 AM

On dangerous batteries -
I have been told that fires can start when battery-operated remote controls for televisions etc. slip down between cushions so that the buttons are pressed for long periods, causing over-heating.

On jumping off aircraft wings -
I believe it's the point where you hit the ground that might cause problems, rather than the jumping.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: gnu
Date: 13 Jan 06 - 02:09 PM

GFCI... Ground Fault Circuit Interruptor. Well, it does prevent you from getting "between line and load". As little as 5 milliamps difference between hot and neutral will trip the circuit. It's very existance is to protect you from getting fried.

GFCI locations... bathrooms, washrooms, outdoors, garages (USA, not in Canada), above counters for sinks and wet bars, unfinished basements (except sump pump or refigerator), crawl spaces, rooves, boat houses, swimming pool equipment, whirlpool baths, jacuzzis, exterior within 6.5' of grade (8' in Canada... must be for our bigger bears).

All houses in the US are wired 220V (240V) at the entrance. The 110 V is gained from splitting the 220V.

Anyone using the newer arc protection stuff? I don't know if it's mandatory yet or not in Canada.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: gnu
Date: 13 Jan 06 - 02:12 PM

Oops... where I said "outdoors"... this is clarified where I said "exterior".

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: McGrath of Harlow
Date: 13 Jan 06 - 02:53 PM

No response to that query about whether chucking the electric fire in the bath would actually be actually a reliable murder technique. It crops up in a fair number of murder stories.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: gnu
Date: 13 Jan 06 - 03:06 PM

Well... if it was plugged into a GFCI circuit... get a gun.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: gnu
Date: 13 Jan 06 - 03:26 PM

By the way. Do not trust a GFCI. Treat every circuit as if it is not protected in any way. I always wear proper work boots. You would not believe the amount of faulty (pun inteneded) GFCI receptacles I have seen in my building inspection buisness. Personally, I would wire all such circuits from GFCI breakers AND use GFCI receptacles... hey, for six bucks a crack, why not? The breakers don't cost any more either.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: JohnInKansas
Date: 13 Jan 06 - 08:29 PM

gnu -

Even GFI receptacles run more like $14 - $18 (US) in my area, while a common 2 socket receptacle is about $0.97. Few mains boxes that I've seen use GFI breakers, and they're not generally required by current building codes in most places in the US, unless there's been a change in the past year since I looked.

A common practice here is to put a GFI receptacle in one location, usually in one bathroom, and run the sockets in other places that need (per code) GFI protection off that one circuit. GFI receptacles commonly available do have "outlput taps" for connecting the wires for that purpose, that put connected circuits "through the GFI," which may explain a difference in price(?).

John

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: GUEST,Jon
Date: 13 Jan 06 - 09:06 PM

RCD and GFI appear to be the same thing. Wonder why they call them GFI's in the US. Until leftydee explained them, promting my earlier question, I thought they were something else, an earlier device (I forget what it was called) I read about somewhere that did motitor the earth leakage rather than the live/neutral.

BTW, I'm sure I've mentioned this before but for the record, as we discovered last year, a slug is capable of getting inside a junction box, melting most of itself into some form goo accross live and neutral which then is enough to trip a 30mA RCD. the electrician we called in had never seen anything like it.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: GUEST,Jon
Date: 13 Jan 06 - 09:48 PM

And the name I was looking for was on the page I gave a link to. It was an ELCB.

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: JohnInKansas
Date: 14 Jan 06 - 02:10 AM

Way back in historical times, in the US, a variety of wiring systems were used, but quite generally the earliest of systems consisted of two wires - a "goesinto" wire and a "goesouta" wire. Wiring in homes and elsewhere was often done with "wire and post" in which bare (or only sometimes insulated) wires were strung post-to-post on glass or ceramic insulators. A little later, it became common to use insulated wire, but the insulation consisted mainly of cotton or linen cloth strips wrapped around the wire and saturated with coaltar pitch or shellac. This is a "not very durable" insulation, but the standoff height of the posts made it relatively unimportant how good the insulation was, as long as it was strung in unoccupied walls and attics etc.

In the era when wire and post installations were done, there was no universal attempt to "ground" anything. Wiring of this kind is still occasionally found still in use by people restoring "historical" homes and other buildings. In areas with "modern" building codes installation of this kind of wiring disappeared prior to 1940 or so. Legal or not, such methods were occasionally used in rural/farmstead homes as late perhaps as the early 1950s ("Uncle E" wasn't really all that up on safety, but had no difficulty getting the components ca. 1948 out on the farm.)

Somewhat later, the use of 2-wire assembled wiring, in which two copper conductors were molded into a single insulating unit became common, and in most areas became required by building codes. At about the time that the molded wire appeared, most codes specified that one side of the circuit must be "grounded" at the "fuse box." In the earliest period when grounded circuits were specified, receptacles where you'd plug in an appliance had two identical parallel slots, so you had no real way of knowing which side was the "hot" slot and which side was the "ground" slot. Systems of this kind were common until sometime perhaps in the late 1940s or early 1950s, and the symmetrical receptacles are still fairly frequently found in "modern" homes (although the mains etc generally will have been brought sort of up to date, - usually - or sometimes - or not).

Recognition that knowing the difference between hot and ground sides of the circuit had some importance led to the use of two-slot receptacles in which the "ground side" slot was a bit wider than the hot side slot. Plugs on appliances where it mattered had a wider blade on one side, so the plug could only be inserted one way. Appliances where it didn't matter had the same size blade on both sides of the plug, and could be inserted either side up. Homes constructed after about 1950 or so, perhaps a bit earlier, will generally have (or had originally) the assymetrical two-hole receptacles, although it's not uncommon to find them "wired backwards."

Sometime in or before the 1950s someone made the remarkable discovery that if the "ground" wire carries a current it doesn't have the same voltage at both ends, and hence at one end or the other it's not really at "ground voltage." Three-hole receptacles became mandatory where there were building codes, although it was probably in the middle to later part of the 1950s before this requirement was generally in place. The wider slot became theoretically the "neutral" connection, and carries the "return" current. The narrow slot is (supposed to be) the "hot" connection. (Miswiring is fairly common.) The third is a round hole, and is supposed to be connected to a true "earth ground." The "ground" wire should never have a measurable current in it except in the case of a malfunction.

The GFI receptacles in common household use in the US generally assume that in order for there to be a "ground line current" there must be a difference between the currents on the "hot" and "neutral" lines, and the difference between these two currents is sensed to determine when the GFI device should trip and interrupt the circuit. By using the difference between two currents, they're insensitive to variations in line voltage, and they can be made very sensitive.

(Sensitivity is good enough that an inductive device like my dog clippers will frequently trip one. The current on both lines is the same, but isn't exactly the same at exactly the same time, during the brief "storage buildup" time in the vibrator coil.)

The "RCD" name may refer to "Return Current Detector" which is a nomenclature now used rarely in the US. What would be called an RCD interruptor would be tripped by the presence of a current in the "third wire." This would respond to an internal short circuit in an appliance, but does NOT reliably trip the circuit if an external return (as through the bath water) is the cause of the fault, where the differential current detection method would. (It's quite possible that other users have updated the method and just retained an archaic terminology.)

Note that dates given here are approximate, based on what I've seen done mainly in one local area. And perhaps not everything that I've seen has been strictly legal. Uniform US National Electrical Codes have been around for a long time, but universal adoption and enforcement is a fairly recent innovation in some places, so there has been a lot of variation across the country. Comments here also apply only to "utility" circuits, sometimes called "lamp circuits." Other rules apply to "heavy appliances."

John

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: gnu
Date: 14 Jan 06 - 06:32 AM

John... your prices may be quite correct. As I get older, I sometimes forget things. Like the fact the I bought a bunch of them on sale for $6 each about ten years ago. Yes, you can always wire "downstream". However, when your house is already wired, it's easier to replace them individually. GFCI breakers are not required in any juridiction I know of... I just like them.

Here's a good one for ya! I am an Engineer. I have managed millions of dollars worth of constrction. As part of the services my company provided, I was in the building inspection business for seven years, including home inspections. When I moved into my present house, a 45 year old bungalow, I made a list of electrical upgrades and went to see an old buddy. He had just retired and his son had taken over the business. Sonny arrived a couple of days later and went to work, as did I, fully confident that I would get a top notch job. When complete, I looked over the work in the house and was pleased.

About six months later, I blew a fuse in the garage disconnect. When I opened the box, I nearly **** myself. Sonny had wired the new exterior GFCI to the line lugs in the box. The next time I saw his old man, I told him about it. He said, "Well, it's hard to find good help these days." Always was a joker. But, you just know what happened when he next talked to sonny. Sonny never did contact me to find out why I wasn't throwing any more business his way!!!

Subject: RE: BS: Shock Risk from AA Batteries/Water?
From: GUEST,Jon
Date: 14 Jan 06 - 07:19 AM

Interesting John, so even the term RCD was used differently in the US. An RCD as given in the Wikipedia link I gave in the UK and elswhere is a Residual Current Device and it would appear to now be understood to mean that in the US. Abbreviations can be dodgy things can't they!

In my UK memory (b. 1960), plugs have always been 3 pin but I do remember a few of the round pin 15A (I think) ones. Our "standard" plug is one of these 13A fused plugs. While this plug is rated at 13A, the internal repacable cartrige fuse may 13A, 5A or 3A as appropriate for the device it supplies. One should always replace a fuse with the same rating.

A common method of wiring sockets in the UK is a ring main where the twin and earth cable goes from the consumer unit to each socket in turn and then back to the consumer unit. This circuit is protected by a fuse or circuit breaker (MCB). Consumer units may be "split load" with some circuits protected by a common RCD and others, eg. lighting (you don't want your house plunged into darkness because of an earth fault on a socket) may be unprotected.

RCD protection can be provided at other levels, eg. a circut could be protected by an RCBO, a device that combines the overload protection of an MCB with RCD protection, RCD sockets are available as are RDC plugs.

I think all wiring in the UK should conform to the (current at the time of doing the job) IEE regulations. A "guide" can be found here