Need Electrical Help.

[BeanAnimal]

There is a LOT that could be said about this topic....

However just remember that for the sake of this example both the 110V and 220V would be on a 15A breaker. That means that twice the POWER is available from the 220V circuit. In either case death will occur long before the current limit is reached.

To answer the question about which will "shock" worse... well they will feel different is the easiest way to put words to it.

The resistance of the human body and skin varies from about 1K ohm for wet skin, to over 10K ohms for dry skin.


Before we get into the details... A defibrillator delivers somewhere in the neighborhood of 6A in a very short burst. If you don't already know... it will stop a heart that does not need restarted.

Lets look at some aproximate shocks at 1 SECOND DURATION

Most humnas "feel" an electric shock at .001A
.005A provides a tingle but does not usually hurt.

At .01A you get sustained muscle contraction. This is the "can't let go point" It may hurt... it may not. Long term shock can cause muscle damage or worse at this level.

At .05A most people have trouble breathing and feel acute pain. Heart problems start to occur. This is where it gets VERY dangerous.

At .1A the current is fully capable of stopping your heart (causing fibrillation). This is certainly deadly

At above .3A you are in sevre risk if death. The heart may initially fibrilalte and then restart, but severe burns and resperatory failure may get you even if your heart spazms don't.

Now back to 110V vs 220V and getting shocked.

Lets take wet skin (we are talking about the fishroom anyway).

1K ohm (1,000 OHMS).

So according to Ohms law at 110V and a resistance of 1,000 ohms... You would recieve a shock of .11A Painful, and possibly deadly after 1 second.

The same shock duration at 220V would equate to .22A of current. Your body in other words would pass twice the current through it!

Bean

 

[jamielind]

after i thought about it a while i figured it out. sometimes i think a little slow. thanks

 

[Cuervo]

I probably should not admit this...

I was a shipboard electrician in the USN. The higher the voltage, the more it hurts, and the more likely you are to not be able to let go.

As Bean pointed out, when the amps start to go up, the muscle contractions become more and more involuntary. In the Navy, as part of Electricians watch, we had to check certain wires for heat buildup.. they always stressed to use the back of your hand.. not your palm. The reason - if you get blasted on the back of your hand you will be thrown free. If you grabbed the wire, you run the risk of not being able to let go.

I've never been shocked by 220V, but I can speak loudly from experience when I say that 440V hurts much much worse than 110V. (the muscle contractions are what hurt)

The best time though.. get shocked by 400Hz instead of 60Hz.. now that will leave a lasting impression of how important safety really is. hehe

I should note that standard policy was that if we got even the slightest shock, we were supposed to report to medical to be kept under observation for 24 hours. After being shocked by electricity, it is possible for a heart attack to occur for some period after the initial zap.

 

[BeanAnimal]

I have my share of 500+ volt DC trolley wire shocks (undeground coal mines). Also got into 575VAC one time, but luckily only got whacked in the arm. I have seen the trolley go to ground before and it is a blinding spectacle. Most of the time it does not trip the breaker (there really is none per say) and the light is blinding until the wire melts in two. We will not talk about the silly things I used to do with a Tesla coil and jacobs ladder (ouch!).

 

[Matrexz]

Ahh Tesla coils are great!!!! Especially when your called in for a noise disturbance and the police come to check it out but they don't have the nerve to actually step through the doorway to see the thing working fully. They said just keep it down.

 

[Cuervo]

500V DC - yeah I bet that hurts like hell. The worst for us was that damn 400Hz though, that's what they use to power the radar sets. You know how 60Hz makes your muscles contract at 60Hz.. yeah now imagine that at 400Hz.

It's probably also worth noting that at the time I served, all Electricians Mates were trained in CPR. I always thought that was smart.

I once heard it said that the Electrical Trade is the #1 trade that kills people.

 

[Runner]

After a couple of accidents in my company, we are finally taking not only shock protection but arc-flash seriously now, too. In our budget that just came out, I am procuring two full sets of arc-flash clothing/face shields/gloves. I am well past the days I work in a live 480 VAC panel without protection.

As for admissions, we all have had our stupid phases in life. I've grabbed live 480 VAC (phase-to-phase between thumb and forefinger) before and it hurts. My hand went numb for about 3 hours after that, too. Only my new 600 VAC insulated work boots and the fact that my other hand was in my back pocket instead of leaning on the panel saved me from a nasty shock or flash-burn. I don't even go near live 120 VAC these days without blue-jeans and a long-sleeve cotton shirt. Polyester and electrical faults are not friends.

Another story: My supervisor at an old job went to open up the main metering section of a 600 VAC switchgear, but it was stuck. He made sure the control power was turned off, then reached around to fiddle with the retaining mechanism. He forgot, though, that they CTs (current transformers) that monitor the current flowing through the main bus are not disconnected when you throw the control power breaker. he was almost up to his shoulder when it grabbed him. He said later he could count the cycles as his body shook. He had no concept of the time that passed before the fuse finally blew and let him go. He was pretty shaken up the rest of the day, but fine other than soreness where he touched the CT terminals.

Sometimes fortune (or divine intervention) favors the stupid. The rest don't live to write about it.

 

[BeanAnimal]

I saw the results of a mine electrician touching shorting a skrewdriver between a 7.2 highline binding post and the equipment frame. I did not see the incident. The man lived, the witnesses said that the flash looked like an a-bomb test and the 18" screwdriver was a nub. The victim was burned and spattered with molten screwdriver and copper... but was luckily not much worse for the wear.

CTs are bad news if they have open secondaries... pretty much unlimited voltage!

The hand in the pocket trick has saved many a hi-pot electricians life. It still makes me wonder what the high-tension service guys are thinking when they get lowered onto the lines by helicopter to keep the chance of deadly ground arcs down!

 

[Matrexz]

They have to be crazy and only think about the money!!!

 

[BeanAnimal]

I dunno... I spent many years working under severe roof falls (cave-ins) on longwall sections of coal mines and have also knowingly worked in 2 mine fires (in an attempt to help control/isolate them). Very dangerous and I surely was not getting rich. Don't ask what was going through my mind

 

[kjord97]

YUP that is why I had 350 amp service built into my house, with 3 20 amp circuits running to my future 180 gal.

 

[Cuervo]

The bottom line -
If you build your own stand, and it fails, you lose your tank and have a big mess to clean up. You DIY your sump and it fails.. another big mess.

The electrical is the only thing I can think of that if you DIY it and it fails might just straight kill you or a family member. Not only that, but if you DIY it and really don't know what you are doing it has a fairly reasonable chance at killing you.

T be totally honest, I always flinch a little seeing electrical advice on these forums, because the chances are if the person is asking, they really should be calling in a pro.

 

[BeanAnimal]

I agree. We all need to learn someplace....but our first electrical training should not be in a 200A service panel. That is why I usually strongly urge the OP to enlist the help of a qualified person.

I provide the answers instead of the smug "call a pro, your not qualified" answer that you find on other forums. The reason: Most people don't listen to NO and insist on moving forward anyway. In that case they should at least be armed with good advice with as many relevant facts and asnwers as possible ANDF as important... fair warning about the consequences and dangers of their intended project.

Bean

 

[Cuervo]

I agree with you, and I think you're on track with the way you answer people's electrical questions.

I feel that most people who haven't worked around electricity know it's dangerous, but don't fully respect it. (until they've been bitten)

I've been trained in the Navy, and had quite a few years as a service electrician, I've even roped houses, but still when it comes to something serious I'd prefer to have a friend in the biz take a look at it.

What we need is one of those animated .gif's like the welcome to ReefCentral one.. but one that show's someone getting lit up, and has a warning label. hehe

 

[BeanAnimal]

At age 14 I dismantled several console TV sets. My friends father warned us about the flyback transformer and storage caps. We did not heed the warning and proceeded to take apart the TVs. To this day the shock I got was one of the worst I have ever experienced. We thought we were smarter than the adults and ignored the warning. We used a screwdriver to short the storage cap. Reaching into one of the sets, my finger touched the hot side of the flyback. The jolt threw me backwards and the sudden muscle contraction of my right arm made me feel like somebody hammered it with a baseball bat. I remember getting black and blue a few days later.

I also had to work on a piece of equipment that had a faulty 3phase 480V 100A contactor in it. It was an emergency situation and the equipment HAD to stay running. This meant holding the contactor in with a long screwdriver. Needless to say the Arc flash and "concusion" each time the contactor shorted was insane and brought back very vivid memories of the flyback transformer incident.

The hope is that most people don't ever need to learn the hard way