# Dangers of Water + Track Power



## ddevoto (Jan 22, 2008)

Many of us have a water feature as part of our layout. I have a trestle running over a waterfall and pond and have DCC track power. I'm wondering the danger of bodily contact with track power and the water. Not willing to "Test the Waters" physically, has anyone had any experience? I worry about my Grand kids safety during train operations.


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## Brandon (Jul 6, 2011)

Pretty minimal. 

Low voltage electricity needs a good conductor to travel very far. Water isn't a good conductor and most train power supplies can't put out enough amps to hurt someone (< 10 amps). Train transformers are also designed to cut out if a 'short' is detected which would be track falling into water.


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## Torby (Jan 2, 2008)

None. 

If your bare foot is wet and you step on the track and you're running pulse power, you can feel the tingle. Most of you wouldn't know about that


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## Randy Stone (Jan 2, 2008)

I wouldn't worry about the track power, but the pump for the pond is a possible real problem. 

Make sure it is grounded and if it is plugged into a wall type plug in receptical, make sure the receptical is one with a ground fault circuitry. 

If you have it wired directly into your breaker box, make sure the breaker is a low amp just capable of powering the pump and no more.


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## Brandon (Jul 6, 2011)

Pump is AC and carries further with less energy loss than DC. AC in water is more worrisome than DC in water. GFI outlets are ab absolute when dealing with water but you can still be killed if a GFI outlet is in use because the GFI's don't trigger faster than power can kill but it's far less likely with a GFI. Best to also use arc fault breakers (10x the cost still) with water IMHO. 

Also normal household AC is 120v with probably a 15 or 20 amp breaker (could be 40, or 50 for some outdoor circuits and depending on how stuff is put together). 

Volts tingle, amps kill. Getting hit with 1,000,000+ volts tickles if there's very a billionth of an amp behind it like what you get in a tesla coil lightning bolt. 1,000,000 volts would travel through water since at that voltage just about anything becomes a conductor, such as air. 

Depending on sweat level on your skin, you can touch tracks and sometimes could feel a little tingle. Barefoot wet foot is also slightly more likely but it's borderline either way. 

20 year old submersable pump in a pond, cord could have UV damage and a wear I'd never step in the water without the pump being unplugged. A month or so ago I remember a daugher and father in a resort near Orlando were both killed when a pool light had been broken and the girl jumped in the pool. Father was killed when he jumped in to save her. Those were likely AC lights and not low voltage DC. That breaker for the pool lighting should have tripped but either failed or was not installed correctly. 

DC voltage under 30 volts and 5-10 amp transformers like what's used for our trains isn't something to really worry about. It won't kill if everything is in correct working order. Electrical outlets in the home, outdoors and AC in water are my first concern. Also a bad christmas light set will shock you more than track would as it's 110v AC, it just looks frail but the gauge of wire in them can still pass quite a bit of current.


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## toddalin (Jan 4, 2008)

If you put 22+ volts on the rails and are working on the tracks on a hot summer day when you are sweating profusely and lay your forearm across the rails, you will feel the "burn" and I'm not referring to a little tickle.


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## Greg Elmassian (Jan 3, 2008)

Brandon, you apparently have not read up on electrocution. 

Do some more reading, it takes very little amperage to kill someone... look it up, don't argue with me. 

And pure water is not a good conductor, but water with any impurities IS a good conductor... and unless your pond is filled with triple distilled water, it is something to consider. 

Again, I'd do some more research and get the answers... under the right conditions, 30 volts could harm you I believe, but it all depends on conductivity... if your skin was nice and wet, I think you can do it with a very low voltage. 

By the way, 24 volts AC is enough to kill a frog, have found several electrocuted on my rails... 

Read this first, which is not perfect, but gives you a basis, where you can be electrocuted with microamps http://en.wikipedia.org/wiki/Electric_shock 

Greg


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## Brandon (Jul 6, 2011)

I don't disagree at all, nor would I argue low amps can kill in a very specific situation but low amperage electricution is outside of the situation the OP is talking about. 

You can't always predict the path current takes through a body, but would be very unlikely if someone did stick a hand into a pond that's electrified by a train transformer for it to find a path through the heart where low amperage can cause cardiac arrest. 

In a properly setup circuit, the moment the track or dcc transformer wiring came into contact with a pond, the transformer and/or gfi should cut power, making any shock impossible. Doesn't matter if someone puts a hand between the track and pond because the common conductivity of skin and the body should not be enough to pass current through the body. 

Frog skin has a completely different conductivity than human because frog skin has a much higher water content and conductivity. Just because you have dead frogs, you can't conclude anything from that except the track power can kill frogs. I'm not sure if in biology they still have students use 9v batteries to cause the muscles of frogs to react, ever put a pv battery to your skin? Nothing. Several day old frog skin still contains enough water and conductivity to react. Now put a 9v to your tongue and you'll get a shock but that's a different situation. I guess a kid could be swimming in a pond and lick the track to increase the risk of current flowing through the heart, but that's likely outside the OP's question. 

In all likelihood, a kid touching both tracks, one in each hand has the highest chance of current flowing through the heart and cause cardiac arrest. Simply adding water does not IMHO increase the risk of kids being around train equipment. There are far more likely killers in a yard than a pond+train transformer risk. Focusing on a .00001% chance when there's a 10% chance of something else in the yard seems like a bad idea until the 10% risk is lowered.


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## Brandon (Jul 6, 2011)

Also, if the track fell into the water at the same time a kid was swimming in it, before the gfi and/or transformer cut out there could be a slight risk for full disclosure. A single hand in the pond when the track fell in I believe the chance of cardiac arrest is so low that other potential killers in every day life are vastly worth time instead to focus on reducing.


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## Greg Elmassian (Jan 3, 2008)

The transformer does not have a GFCI circuit, nor could it have, since the DC output is not referenced to ground, like ac signals. (Although such a thing could be designed). 

The conductivity of your "body" goes up depending on how much of your skin is wet.... are we forgetting the warnings about appliances in the bathtub? 

Yes, my only concrete conclusion in my statement above is that my DCC can kill frogs.... 

I was just reacting to your statements that it was impossible, and I don't agree... doesn't mean we should live in fear of our lives with track voltage and ponds, but saying it could not happen is not true. 

Also, I did not see the caveat in the op where it was guaranteed that only one hand would be wet... 

from the OP: " I'm wondering the danger of bodily contact with track power and the water." 

the question of the worst case is the kid gets all wet, and then grabs a rail with each hand, putting the voltage through his chest and heart.... is there danger there? 

There's plenty on the Internet, and I'm saying that anyone that just says it's impossible needs to do more reading. 

Greg


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## toddalin (Jan 4, 2008)

Posted By Brandon on 06 Aug 2012 02:54 PM 
Also, if the track fell into the water at the same time a kid was swimming in it, before the gfi and/or transformer cut out there could be a slight risk for full disclosure. A single hand in the pond when the track fell in I believe the chance of cardiac arrest is so low that other potential killers in every day life are vastly worth time instead to focus on reducing. 

If the track "falls in the water" with 24 volts on the rails, nothing is going to cut out and that track will stay live. It's no different than when I'm watering my yard and my track becomes submerged and the trains still go through the puddles. Nothing trips.

If a 120 volt line or the transformer falls in the water, the GFI _should_ do its thing.


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## wigginsn (Jan 9, 2008)

'Danger' meaning the ability to kill (fibrillate), assuming 24 VDC, pretty much non existent. Would the kids feel something if they grabbed both rails with a sweaty hand? Quite possible.. 

There can be no exposure to shock between the track and a pond in normal circumstances unless one side of the DC source is grounded. I would think this is very unlikely but cannot speak for every installation. If it was - see above. 

All bets are off on the AC side, answer is it depends.. Read IEEE80 / IEC60479 if you really want to know. 

Cheers 
Neil


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## Dan Pierce (Jan 2, 2008)

It only takes 50 micro amps to kill. 

Of course the path of current flow has to be right for that to happen. 

Whether it is AC or DC does not matter.


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## Greg Elmassian (Jan 3, 2008)

Dan, read the second paragraph of the wikipedia link I posted above AC is different from DC in how it affects people. 

" The minimum current a human can feel depends on the current type (AC or DC) and frequency. A person can feel at least 1 mA (rms) of AC at 60 Hz, while at least 5 mA for DC. The current may, if it is high enough, cause tissue damage or fibrillation which leads to cardiac arrest. 60 mA of AC (rms, 60 Hz) or 300â€"500 mA of DC can cause fibrillation" (this is on dry skin, by the way) 


I love you guys, but you all ought to do a bit of research before you make absolute statements... When you say usually, often, rarely, it's usually (see my caveat?) easy to get the "gist'. 

But as soon as you say "never", "always", "impossible", or "makes no difference", you are opening a much bigger world. In all my training as an engineer and applied physicist, those words were VERY RARELY used, because there are very few absolutes in nature. 

Greg 
"


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## krs (Feb 29, 2008)

Another thread related to electricity/electronics with more false information than correct one. 

Starts right with the second post 

Low voltage electricity needs a good conductor to travel very far. Water isn't a good conductor and most train power supplies can't put out enough amps to hurt someone (< 10 amps). Train transformers are also designed to cut out if a 'short' is detected which would be track falling into water. 

The conductivity of water was already commented on, but the other parts of the statement above require correction. 
To start with, a train power supply can put out plenty of amps to hurt someone; the < 10 amps, less than 10 amps also doesn't make any sense, the danger level for the human body is in the low * milliamp * range, milliamps as in one-thousands of an amp. 
Luckily the amount of current a power supply can deliver doesn't determine how much current flows through your body when you come in contact with the power supply output somehow, the current that flows depends strictly on the voltage and the resistance (of the body including skin and tissue). 
Then the next part of this quote: "Train transformers are also designed to cut out if a 'short' is detected which would be track falling into water." - 
That statement is in crotradiction with what was stated at the beginning of the quote - "Water isn't a good conductor" - if it's not a good conductor how can a power pack possibly detect track falling into the water as a short? 
Fact is that no train transformer is going to cut out if the track falls in the water or gets wet - people run trains in the pouring rain all the time. 

Bottom line for ddevoto is: 
1. Don't worry about the power running the trains and its proximity to the water. Kids may get a slight shock if they are soaking wet and touch the powered track but that is not going to kill any one or cause any harm, but 
2. Do worry about water and the household 115 volt connections and lines. A GFI is an absolute must, the electrical code usually requires that for any out door outlets, also indoor ones located in bathrooms, sometimes kitchens, where ever 115 volt power and water can come together (with a human body in between). Also test your GFI on a regular basis, that only takes a second and you want to be sure it trips if ever required. 

But otherwise, enjoy your trains and your grand kids.


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## Brandon (Jul 6, 2011)

Good thread, thanks for correcting my bad information. So many things to learn.


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## ddevoto (Jan 22, 2008)

Thanks for all the input. Electrically outside I'm "all GFI'd up" and realize all the danger the 120v pump poses. I brought this subject up because of my own curiosity and I've never seen any discussion on the subject. Never have see an article regarding Water + Track Power safety in GR magazine. This is an important subject, it seems most GRRs have some sort of water feature.


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