Electrocution of my sister

My sister is addicted to the bath tub and can easily stay in a warm tub with the water trickling an entire day. She lets out water every now and then to keep her water level at her preferred place approx. 3" above her belly button.:rolleyes:

Anyway, for some time now, my bath addicted sister has been putting a board across the top of the tub like a desk top and uses her lap top (with mouse) to do her home work and surf the internet (complete with DSL, mind you). Since my sister is an adult, there’s not a lot anyone can do to stop her from risking her life in a dangerous game of Bath Russion Roulette, but what exactly are the chances of her actually dying if her lap top or mouse did happen to fall in the bath water? If that happened, would she actually die or just be affected mentally from the electrocution for some time?

Since laptops use AC power, she runs the risk of…wrecking her laptop. Unless she allows the power adapter to fall in, then she might have some trouble. I am not an electrician, so I’m not 100% sure on this

I think the biggest risk of this kind of electrocution comes from allowing mains-powered equipment to come into contact with the water; most laptops are not directly mains-powered (there’s usually an adaptor and the machine runs on something like 20 volts) - I don’t know how big a risk this is. There’s a possibility that the batteries could explode, or produce an explosive mix of Hydrogen and Oxygen (although I suspect it would be quite unusual for this to build up to dangerous levels in a very short time) if shorted out by water

Just a picky point, but to be electrocuted means to be killed by electricity. It is not a generic term for getting zapped. So technically, she would have to die to be electrocuted, so therefore, the electrocution would kill her.

No, I’m not anal…the mistake was recently pointed out to me.

As to what you obviously asked, I don’t know :slight_smile:

Well, it’s not the safest conceivable practice because even a 100 milliamps of current can kill you by inducing cardiac arrythmias. (http://www.portfolio.mvm.ed.ac.uk/studentwebs/session2/group62/electro.htm) You’re usually safe at low voltages such as are produced by an AC adapter, but if you are wet, then the resistance of the skin is significantly lowered. AC is more dangerous than DC, so I’d suggest running on battery power alone. If your sis must use the adapter, I’d make sure that it was plugged into a GFI (Ground fault interrupter) circuit. (Most bathrooms up to code should have these.)

I just had a thought. You realize that all the men on this forum are now picturing your sister in a tub wearing nothing but a laptop and a smile:D…she might not be happy about that!

She has two levels of protection:

  1. Ground Fault Circuit Interrupt outlet (I’m assuming it’s operating correctly)
  2. Isolation

#2 is due to the fact that the power converter, whether it be a linear or switching unit, utilizes a transformer.

So I think she’s pretty safe as long as both are operating correctly.

It would be easier to evaluate the risk if we had a photo of your sister using her laptop in this manner.

Take no chances. Get lots of life insurance on your sister with you as the beneficiary.

The other thing to know is that she is not in as much danger from the computer or transformer falling in the tub as she is from touching an ungrounded source while standing in the tub. Frequently movies or TV show a person being killed when an appliance falls in the tub. While this would be bad (shockingly so) it is not the worst case scenario because while the person is likely to be part of the circuit at that point they are probably not all of it. In other words the device in the water will conduct through the water and the person to the drain (which is probably grounded). If a person is in the tub and touches a current source out of the water then all the current will pass through the person to the water to the drain. Very very bad.

In other words worry more about her contacting something dangerous outside the tub slightly more than about her dropping anything in to the tub. If she was just using the laptop on battery power then she probably won’t get hurt and will just fry the laptop.

I think as long as she has the mouse and laptop and DSL she should also get a webcam. I’m sure that we could take up a collection for her quickly enough.

Not directly applicable, but Cecil Adams answered the question of Can you be electrocuted while on the phone in the bathtub?

my .02:

not a problem.

DC is much more dangerous than AC.

There is a HUGE difference between current flowing over your skin and that flowing through the internal fluids.

for sure: the mouse (and/or keyboard) are not lethal.

If the mouse fell into the water she would just ruin the mouse (it might be ok once it dries out). If the entire laptop went in then most likely just the laptop would be ruined. When she tries to take it back out of the water, then there is a very nice conductive path from the main circuit, through the laptop, THROUGH HER, into the tub, then through the water pipes to ground. It’s the worst kind of shock since the electricity would come in through the hands and leave through the feet (or whatever parts of her are still in the water) which means that the electricity goes through the chest.

Tell her if she does manage to drop the laptop in the water, get out of the tub, unplug the laptop, and then and only then pull the laptop out of the water.

Also tell her that if the outlet she is connecting the laptop to doesn’t have a GFCI that she better get one installed. It’s code on new houses but a lot of older ones don’t have them.

Water is a fairly poor conductor. It’s good enough that it can conduct more than enough current to kill you, but it’s poor enough that it’s not going to look anything near like a dead short to the batteries. They won’t explode or swell or do anything nasty.

Electricity kills you generally in one of two ways, either it interrupts your heartbeat or it cooks you. Someone who gets a jolt from an electric chair or a lightning bolt is certainly going to have a lot of cooked parts, and they might experience brain damage. You’re not going to get that level of current through the laptop unless you drop the power supply in with it. The only real risk comes from the current possibly interrupting the heartbeat. It takes a significant amount of current to cook you to death, but it takes a surprisingly small amount of current to get your heartbeat out of whack. Once it gets all out of whack a good thump with a portable defib unit will probably knock it back into a normal rythm, but this requires that someone be in the bathroom at the time and that you actually have a portable defib machine there (both of which aren’t very likely for most people, who take baths alone and without any medical equipment nearby). Your heart usually won’t go back into a normal rythm all by itself.

My best guess is that she might get a mild tingling sensation with no after effects at all, certainly no mental damage. But I can’t rule out the possibility of death.

I think that this incorrect- AC is more dangerous because it can produce arrhythmia even at low currents. Check out Thomas Edison’s various demonstrations. JDM

I speak from experience (a few times a week), getting shocked from AC current is always a bigger thrill that DC current. And the airplanes I work on run on 400 cycle electricity, not 60 cycle, which causes some the shocks to hurt even more.

Boy, that was imaginative. What you are forgetting is that the power to the laptop is through an adaptor, which has a transformer so the ground is not applicable here.

What that means is if you take the positive terminal from an adaptor and try to measure the voltage between that and a ground (pipe, etc. etc.) u’ll not see any voltage :).
Even if there was a problem with the adaptor, there is a GFCI in all bathroooms (OSHA Regulation - GFCIs are provided for any outlet within 6 feet of sink, tub, etc.)

GFCI works likes this, It measures the current going through the live wire and the current returning through the neutral. If there is any difference between the two, it trips.

Try dropping a hair dryer or something into the sink water next time and see the GFCI trip :slight_smile:

On a related question - I know what they are supposed to do, but is it true that if a GFCI is working properly, you cannot reasonably be shocked?

I mean - let’s say I’m have two bare wires coming off of a cord that is plugged into a GFCI, whilst sitting in a highly conductive tub and water, that is well grounded. If I grab them, and there is a GFCI in the line that is working well - will I feel any shock at all? Will I feel a short burst (which could kill me anyways)? Has anyone here ever involuntarily tested a GFCI in a manner that might have resulted in their death otherwise?

And here’s another query - if you put two GFCIs in series on the same circuit, does it follow a standard joint probability rule for determining the likelihood of failure?

Good Coal (Anthracite), GFCI is not foolproof but it is a good safety device for preventing shocks. Just like Seat Belts in car, these can fail too, but they don’t most of the time.

Neisha, if you are very concerned and rich and so phobic, buy http://www.thenerds.net/productpage.asp?pn=880881, an isolation transformer. You will not get a shock, if you touch a terminal of this and water. However, u’ll get a shock if you take wires out and mess the way, anthra did.

Nothing is foolproof, because fools are so ingenious :slight_smile:

Yes I agree with several earlier posters. Some of us may be able to make additional comments or suggestions if we could actually monitor her bathtub activities visually.

As soon as the webcam is up, please post the URL.