Tossing a charged Capacitor in the Bathtub

[jw]

Most people know that dropping a cord or appliance that is plugged into an outlet into a bathtub filled with water will electrocute the person in the tub. Yet, you can drop a low voltage item such as a flashlight with batteries in the tub and no one will be hurt. Even a set up jumper cables connected to a car battery would not likely do anything, or might just tingle a little (never tried this, but I've handled plenty battery cables while standing on wet soil in wet shoes and never felt a thing).

Not that I'm planning to test this, but what would happen if a large capacitor, charged with 200 volts or more was tossed into a filled bathtub while someone was in the tub? (By large capacitor, I dont mean the size, but rather, I mean a large capacity, such as 500 MF or one Farad or more....).

I see no reason this would ever occur, but I'm just curious.

[NOTE: This could be DC or AC]. DC capacitors are used in electronics, while the AC type are motor start capacitors.

[Stormin Mormon]

AC caps don't contain any energy, when you take them out of the circuit. They only function while the device is running.

DC cap would not contain enough energy to do much. And the power would short terminal to terminal, not terminal to ground.

Short answer (ha ha), is not much.

Christopher A. Young Learn more about Jesus

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Not that I'm planning to test this, but what would happen if a large capacitor, charged with 200 volts or more was tossed into a filled bathtub while someone was in the tub? (By large capacitor, I dont mean the size, but rather, I mean a large capacity, such as 500 MF or one Farad or more....).

I see no reason this would ever occur, but I'm just curious.

[NOTE: This could be DC or AC]. DC capacitors are used in electronics, while the AC type are motor start capacitors.

[Stormin Mormon]

You could write a good murder mystery about this. Like most of the MacGuyver episodes, the science would be worthless, but the story could be fun.

Miss Marple finds the murder weapon: a charged high voltage capacitor taken carefully from the high voltage section of an old television and...... and the murder was shocking.

Christopher A. Young Learn more about Jesus

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Not that I'm planning to test this, but what would happen if a large capacitor, charged with 200 volts or more was tossed into a filled bathtub while someone was in the tub? (By large capacitor, I dont mean the size, but rather, I mean a large capacity, such as 500 MF or one Farad or more....).

I see no reason this would ever occur, but I'm just curious.

[NOTE: This could be DC or AC]. DC capacitors are used in electronics, while the AC type are motor start capacitors.

[Bob_Villa]

My assumption would be...there is no path to ground-so no one would get electrocuted. I wouldn't try it though!

[Evan]

Maybe, just maybe, if it was a *flux capacitor* you would be transported back in time before you asked such a silly question...

~~ Evan

[Doug]

Like to live on the edge do you ??? I'd like to ask you next to test gravity by jumping off your roof but I won't. I think I already know the answer.

[trader4]

That's how it works in the movies. In reality, to be electrocuted the person in the tub would have to be in the path of enough of the current to kill them. That depends on many factors. At one extreme, if the appliance went into one end of the tub near a ground source like perhaps the drain, while the person was standing in the other end, not touching anything else, it's unlikely they would be electrocuted.

On the other hand, if you're holding a grounded faucet with one hand and trying to pick up the appliance that fell in the tub with the other, that's a lot more likely to produce a bad result.

As for a cap, since the current path would be from one terminal to the other, it's unlikely enough current would make it through anyone's body in the tub. Unless they were grabbing the cap....

[Ralph Mowery]

You never have seen a capacitor big enough. While I do not know what effect dropping one in a bathtub would do, I do know what a big one will do to a person when touched to the skin.

Ever seen anyone shocked with the deliberator ? I have seen that several times. The people usually come off the bed a few inches due to the muscle contraction. That is a big capacitor charged up and then put to the skin of a person. Charge a few thousand microfarads to around 2000 volts and touch it. Chances are you will not live or will have body parts missing.

While many times an AC capacitor will not contain much energy, if it is taken out of a circuit when the voltage is at its peak, it will be charged to that voltage and will shock the fool out of you depending on the capacity of it.

[DerbyDad03]

I don't know what will happen when you toss it in the water, but I know what will happen when a dead man stick is used to short the terminals of a large cap charged up to 7 or 8 KV DC.

A dead man stick is a device with a wooden handle with a hooked rod threaded into the handle and a braided strap with a clip on the end. It was used to both ground towers and other electrical equipment or to pull an energized human from said equipment.

At a minimum, shoting out the cap will cause a bang and a spark that is sure to strike fear into the hearts of most mortal men. In some cases, it will blow 4 inches of threaded rod out of the hardwood handle.

We used to do it quite often when I was in the Coast Guard as training/ warning exercise.

We had large oil filled caps (5F) that ran at 15 - 20 KV DC in the LORAN transmitter buildings. We didn't want non-Transmitter Techs in the building without one of us present. As new men would arrive at the station, part of the orientation meeting included a demo where we would use a Hi-Pot to charge up a cap to at least 5KV DC, turn out the lights and then short it out with a dead man stick. One time we went a bit overboard with the Hi-Pot and I was left holding a smoking hard wood handle while my buddy retrieved the metal rod from across the room. We grabbed another dead man stick and still got quite a bang out the cap since it didn't completely discharge before blowing up the other dead man stick.

That one even scared me!

[Art Todesco]

AC will kill as it causes fibrillation. DC will cause 1 pulse. That said, voltage levels, conductivity of the water will determine what will happen. But probably because the 2 poles are so close and the capacitor is not referenced to ground like the plugged in radio, as others said, current will go between the 2 capacitor leads. You will, with DC from the capacitor, produce hydrogen and oxygen bubbling off the 2 leads.

[Tony Miklos]

That's just plain silly. The charge it has depends on where the sine wave was at when it's taken out of the circuit.

[Tony Miklos]

Well there is one hell of a difference between 500mf and 1 farad. Although 1 Farad 5 volt caps have become quite small, one rated at 200 volts might bludgeon them to death if it hits them in the head, charged or not.

Lots of AC rated caps are used in electronics.

[Jules Richardson]

Effect of dielectric absorption, possibly? You short it briefly, it discharges, but then a small portion of the original charge level appears to come back moments later...

cheers

Jules

[DerbyDad03]

I am familiar with that phenomenon, although in this situation, I'm pretty sure it was the result of a partial discharge before the grounding rod exploded. Obviously I can't proof it, that's just my guess, based on prior experience with these large caps.

As part of our bi-weekly transmitter maintenance, we would ground the caps prior to removing the bus bars to get them out of the stand-by transmitter. Before they were even lifted out of the transmitter, we always put a shorting cable on them to stop them from charging back up due to both dielectric absorption and the strength of the signal from the on-air transmitter.

On the rare occasions that we forgot to do this (newbies!) or noticed a bad ground connection, we would use a dead man stick to short them before grabbing them. Even after a few hours, the discharge was minimal and we might get a little bit of a pop. In the case of the training demo, which was done in a rather neutral environment (the mess hall, a 1/4 mile from the transmitter building and tower) the resulting discharge was quire substantial, much higher than anything we'd seen in "real life".

[micky]

I don't think direct current tingles.

I call them polarized and non-polarized.

>

[micky]

IIRC and I do, the big and dangerous high voltage capacitor in a tv set is the picture tube. It doesn't seem liike a practical weapon if removed from the tv set.

[micky]

That's what I've been saying. Well, I said that if you throw a radio or heater in the bathtub, the current will go through the drity soapy water sononer than it will go thourhg the bathers body. What is dangerous is catching the radio when your hand is out of the tub and the only way to ground is through you.

I need volunteers to check this out. It pays 100 dollars per test, to you or your heirs.

[jw]

If you caught the radio before it hit the water, nothing would likely happen, since it's all plastic. Unless it's one of those real old tube sets with a metal cabinet and hot chassis.

Now this brings up another question. If the tub is plastic or fiberglass, water supply is pex or pvc and drain pipes are pvc, the tub is not grounded. I always wondered what would happen, since the person inside is not really grounded. (I mean is an AC plugged in device hits the water ????????

Careful, there might be somneone stupid enough on here to try :) Some other newsgroups there are definately stupid enough people... lol

[jw]

I already know that answer. Last year I stepped off the roof onto an aluminum ladder and the ladder buckled and I went with it. The doctor in the ER said I was lucky to land on my ass. Nothing was broke but I sure had a sore ass for awhile, along with the middle of my back that first hit a lawn chair. The chair did not survive, it was crushed.

I'll never own another aluminum ladder!!!!

[Bob_Villa]

Maybe the Mormon will try it and will lose him forever! *L*