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| MacGyver1968 |
 Posted: Fri Aug 25, 2006 1:37 pm Post subject: Would dropping a radio in a bathtub kill you? |
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Forum Bachelors Degree
Joined: 11 Aug 2006
Posts: 498
Location: Dallas, Texas
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DISCLAIMER: DO NOT try this at home!
We have all seen it 1000 times in the movies and tv. Someone is bathing in a bathtub, and the villian drops an electrical appliance into the tub. The result: Large electrical arcs spew from their body with lots of sparks, convulsions and smoke...and one dead starlet. Sometimes they go so far as to use battery operated devices, or a swimming pool.
My friends and I had a recent debate about this, and I was hoping to get y'all's opinion.
I'm an electronic technician, and have at least a medium knowledge of electricity. It is my contention that submerging any standard 120VAC device (excluding devices that use a step-up transformer, like a t.v.) in a bathtub would not kill you, but at best just give you a mild shock. I have been shocked by 120v countless times, and have never been burned or hurt. Here's how I came to this conclusion:
-Electricity follows the path of least resistance. In most devices, where the power cord attaches to the board, the distance between the hot and neutral wires is only a few mm. Seems to me, most of the current would just jump from one terminal to another. Only a portion of the actual voltage would energize the water, looking for another path to ground.
-Water does not conduct electricity as well as the movies would like you think. The resistance of the water would cause a voltage drop...plus your skin has resistance also. 120v is not enough potential to overcome this to a lethal level. (unless you have a heart condition or pace maker)
-Floating in a bathtub, your not grounded (unless your touching the drain or spout) so there's no path to ground. Most bathtubs are covered in enamel or plastic so there's nowhere for the juice to go.
I could be totally wrong about this...I mean, why would they make GFI outlets mandatory in bathrooms? I would greatly appreciate your opinion about this. |
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| sungmintd8 |
| Posted: Fri Aug 25, 2006 4:45 pm Post subject: |
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Forum Freshman
Joined: 14 Aug 2006
Posts: 34
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It would probably have to be DC (and high voltage) to kill. Battery operated probably wouldn't kill. Also, it would seem from my knowledge of capacitors that it would just jump from wire to wire. The object would obviously short out.
I don't think it would kill. Maybe higher voltages, DC outlet and such might create a plausible scenario, but I don't want to go into extensive testing on this.
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| CaveatLector |
| Posted: Fri Aug 25, 2006 4:55 pm Post subject: |
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| Quote: |
I don't think it would kill. Maybe higher voltages, DC outlet and such might create a plausible scenario, but I don't want to go into extensive testing on this. |
Without a GFI, it most certainly can kill you.
The short draws a lagre current, enough to put a significant amount of amperage across the water to your body. The electricity flows mostly around, but some goes through your body, across your heart, and to the drain.
I'm not entirely sure if it is a requirement to be touching the drain or not.
A good question, indeed.
It takes a mere 6 millivolts to stop that beautiful red beating member of the circulatory system.
What's a DC outlet, by the way?
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| Ophiolite |
| Posted: Fri Aug 25, 2006 5:21 pm Post subject: |
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Forum Radioactive Isotope
Joined: 25 Jul 2005
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Location: Scotland
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| You have also ignored the fact that in many parts of the world the standard voltage is 220/240. That does pack much more of a whallop and is one of the reasons that UK power plugs are solidly built in comparison with the novelty store versions used in the US. |
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| CaveatLector |
| Posted: Fri Aug 25, 2006 5:29 pm Post subject: |
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| Ophiolite wrote: |
| You have also ignored the fact that in many parts of the world the standard voltage is 220/240. That does pack much more of a whallop and is one of the reasons that UK power plugs are solidly built in comparison with the novelty store versions used in the US. |
You guys have power now!?
Holy Christ, I could have sworn you guys were still using torch lamps and tree sap last time I was in Edinburgh.
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Cogito, ergo doleo.
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Last edited by CaveatLector on Fri Aug 25, 2006 9:11 pm; edited 1 time in total |
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| MacGyver1968 |
| Posted: Fri Aug 25, 2006 6:18 pm Post subject: |
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Forum Bachelors Degree
Joined: 11 Aug 2006
Posts: 498
Location: Dallas, Texas
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Good point, O
I used to design tanning beds for sale overseas, and I had to build a power supply to output 220 vac /50 hz @ 60A. ( it was huge)
That's why I specified 120v vs. 220v. I've been bit by 220 and it was NO fun. 220v is a whole different story. THAT might actually kill you.
Cave, you talked about a short...but it wouldn't be a direct short since the water would provide some resistance.
Let's say for sake of example, we're dealing with a 120v circuit, with no GFI or earth ground, on a 10 amp breaker. |
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| CaveatLector |
| Posted: Fri Aug 25, 2006 9:06 pm Post subject: |
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| Quote: |
| Cave, you talked about a short...but it wouldn't be a direct short since the water would provide some resistance. |
Can we ohm out water?
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Let's say for sake of example, we're dealing with a 120v circuit, with no GFI or earth ground, on a 10 amp breaker. |
1. I have little doubt that this would have the potential to kill a human being.
2. The breaker probably wouldn't trip in time.
3. It takes 1/1667 of the breakers max rating across your heart to send you permanent swimming. So unless the combined resistance of your body and the water is less than 20,000 ohms or so, you're screwed.
Of course, testing the scenario is the only way to be completely accurate.
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Cogito, ergo doleo.
There's a fine line between genius and insanity. I have erased this line.
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| Ophiolite |
| Posted: Fri Aug 25, 2006 9:33 pm Post subject: |
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Forum Radioactive Isotope
Joined: 25 Jul 2005
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Location: Scotland
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It is now several decades since powerpoints in the bathroom (other than for electric razors, with a unique plug/socket type) were outlawed in the UK. Conventional light switches are also illegal. All electrical items must be switched by cord pull.
The reason for this was the number of deaths each year of people who either had a radio fall into the bath, or who switched the light on while standing in the bath.
In short, we have already carried out the experiment in the UK. The results were unsatisfactory from a survival perspective.  |
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| MacGyver1968 |
| Posted: Fri Aug 25, 2006 10:25 pm Post subject: |
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Forum Bachelors Degree
Joined: 11 Aug 2006
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Location: Dallas, Texas
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| CaveatLector wrote: |
Can we ohm out water?
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I just used my multimeter to test the resistance of a small container of water, but I was not able to get a stable reading, I got anywhere from 20K to 100k ohms of resistance..but those readings are not anything I would hang my hat on. According to wikipedia, pure water doesn't conduct at all...it's the dissolved impurities that conduct, so how pure the water is out of your tap determines the resistance. If anyone can find a more definite answer, that would be appreciated. I've heard that clean, dry skin has a resistance of about 33kohms, but once again that is not definate. |
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| (In)Sanity |
| Posted: Sat Aug 26, 2006 11:04 pm Post subject: |
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Forum Cosmic Wizard
Joined: 19 Oct 2004
Posts: 2082
Location: Phoenix AZ
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| It was funny, I was watching a CSI episode once and some woman got killed by tossing some kind of heater in to a hot tub. Well the stupid part of the show was that it was plugged in to a GFI outlet. They didn't even try to hide that fact or explain it away as malfunctioning..etc. |
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| Scifor Refugee |
| Posted: Mon Aug 28, 2006 12:07 pm Post subject: |
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Forum Ph.D.
Joined: 02 May 2005
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| (In)Sanity wrote: |
| It was funny, I was watching a CSI episode once and some woman got killed by tossing some kind of heater in to a hot tub. Well the stupid part of the show was that it was plugged in to a GFI outlet. They didn't even try to hide that fact or explain it away as malfunctioning..etc. |
I once watched a CSI episode where a person was electrocuted by a standard 12 volt car battery that had been attatched to a flag pole. The flag pole was hanging out horizontally above a doorway. A person jumped up and grabbed the flag pole (with his feet completely off the ground!) and was killed. |
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| (In)Sanity |
| Posted: Mon Aug 28, 2006 12:30 pm Post subject: |
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Forum Cosmic Wizard
Joined: 19 Oct 2004
Posts: 2082
Location: Phoenix AZ
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| Scifor Refugee wrote: |
| (In)Sanity wrote: |
| It was funny, I was watching a CSI episode once and some woman got killed by tossing some kind of heater in to a hot tub. Well the stupid part of the show was that it was plugged in to a GFI outlet. They didn't even try to hide that fact or explain it away as malfunctioning..etc. |
I once watched a CSI episode where a person was electrocuted by a standard 12 volt car battery that had been attatched to a flag pole. The flag pole was hanging out horizontally above a doorway. A person jumped up and grabbed the flag pole (with his feet completely off the ground!) and was killed. |
Ok, major LOL on that one. |
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| CaveatLector |
| Posted: Mon Aug 28, 2006 5:52 pm Post subject: |
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Forum Sophomore
Joined: 01 May 2006
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Location: Turn left at the second light, three houses down on the right. You can't miss it.
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| MacGyver1968 wrote: |
| CaveatLector wrote: |
Can we ohm out water?
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I just used my multimeter to test the resistance of a small container of water, but I was not able to get a stable reading, I got anywhere from 20K to 100k ohms of resistance..but those readings are not anything I would hang my hat on. According to wikipedia, pure water doesn't conduct at all...it's the dissolved impurities that conduct, so how pure the water is out of your tap determines the resistance. If anyone can find a more definite answer, that would be appreciated. I've heard that clean, dry skin has a resistance of about 33kohms, but once again that is not definate. |
There certainly are numerous variables. I'm positive it doesn't kill every time, but I think the overall question has been answered, in an acutely reasonable fashion, by Ophiolite and I myself.
Would dropping a radio in a bathtub kill you?
Generally, yes.
_________________
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Cogito, ergo doleo.
There's a fine line between genius and insanity. I have erased this line.
Oscar Levant |
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| MacGyver1968 |
| Posted: Wed Aug 30, 2006 9:15 pm Post subject: |
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Forum Bachelors Degree
Joined: 11 Aug 2006
Posts: 498
Location: Dallas, Texas
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cave,
I'm sorry, but I have to disagree with you.
I don't believe with 120 you would die.....maybe with greater voltage..like 240...but as many times as I have received a shock with 120 directly....I don't see how it can kill you. I guess we can agree to be disagreed.
Mac |
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| The P-manator |
| Posted: Thu Aug 31, 2006 10:21 am Post subject: |
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Forum Bachelors Degree
Joined: 26 Nov 2005
Posts: 485
Location: Toronto
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| Ophiolite wrote: |
| You have also ignored the fact that in many parts of the world the standard voltage is 220/240. That does pack much more of a whallop and is one of the reasons that UK power plugs are solidly built in comparison with the novelty store versions used in the US. |
The UK? You are ignoring the rest of the world also has much much much (I could go on forever like this) better plugs than the North America.
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Fight for our environment and our habitat at www.wearesmartpeople.com. |
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