Tankless, instant hot water heater

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marshallf3

Joined Jul 26, 2010
2,358
That was written in 2002, there have been two new versions of the NEC released since then. I don't have one in hand but even if I did I'd be too tired to look it up. I can say I recall some changes being made regarding this though.
 

cjdelphi

Joined Mar 26, 2009
272
Maybe the mexican's don't know what an Electrocution death is? maybe they get 10 a week of people dying in showers and they all just assume something else? natural causes um murder?....
 

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jjj

Joined Feb 25, 2007
116
You wonderful members deserve to know how the "saga" ended: The eBay vendor refunded me the money paid in full, including both postages; i.e. the shipping they paid to send me the (5) water heaters and the return postage. What more do I could wish for?

The safety issue is to do with the Brazilian manufacturer of these units than with the resellers. Chances are the reseller is not selling these units on eBay anymore, because I don't think I am the only one perceiving the 100V leakage.
Thanking you all for your opinion on that product. It helped me greatly to explain to the manufacturer why these heaters are unsafe and to understand my electrician safety concerns. Thx again, for your help. :)
 

tom66

Joined May 9, 2009
2,595
I would be interested to know how dangerous they really are. In theory, they should be a safety hazard, but are the manufacturers pulling several tricks which makes them *technically* safe (but also incredibly dangerous if incorrectly installed?)
 

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jjj

Joined Feb 25, 2007
116
I would be interested to know how dangerous they really are. In theory, they should be a safety hazard, but are the manufacturers pulling several tricks which makes them *technically* safe (but also incredibly dangerous if incorrectly installed?)
I suppose they try to put the blame onto the electrician. Mine categorically refused to install that garbage. It's a wise move, for he doesn't want to lose his license and even less kill off his customers.
 

Norfindel

Joined Mar 6, 2008
326
I seen something similar installed a lot of years ago in a camping, but this model seemed to be isolated, because while i was thinking if it was logical to step below that thing, it smoked as water started to flow from the junctions. I demanded that power remained cut. I was never so happy to bath in cold water.

Maybe the water droplets spread and current won't flow, but i wouldn't bet my life on that, as the conditions are almost ideal to die, and anybody can potentially touch the shower and die anyways, because then there's no separation beteween 220v and your hand. I prefer gas systems to heat water, thank you.
 
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sceadwian

Joined Jun 1, 2009
499
Norfindel, if the conditions are ideal to die could you please reference a known death using such units? I don't care how cheap you are or what the laws are in your country, units like that aren't installed if there is a serious imminent risk to human life, potential sure, eminent no. Mind you stupid installers increase the chance of immediate injury or death with any device let alone an electrical one.

I worked at a real... quality place once, this was before I got there but I'd heard stories that one of their electricians had actually wired up the steel super structure of a hoist to carry live 220, mind you this was in a wet environment. No one died there or was seriously injured.

It is in all honesty VERY difficult to get electrocuted even if something is wired so horribly wrong as to make it relatively dangerous.
 

beenthere

Joined Apr 20, 2004
15,819
Norfindel, if the conditions are ideal to die could you please reference a known death using such units? I don't care how cheap you are or what the laws are in your country, units like that aren't installed if there is a serious imminent risk to human life, potential sure, eminent no.
It's funny how discussions of electrical hazards brings out all sorts of attitudes. Policy here is not to finely distinguish between a mere potential lethal shock hazard, and one that is proven fatal. The potential is quite enough to urge non-usage.

What is the point here? -
I'd heard stories that one of their electricians had actually wired up the steel super structure of a hoist to carry live 220, mind you this was in a wet environment. No one died there or was seriously injured.
How likely does that sound? How does the wet environment affect the hazard? Is there any corroboration to the use of the structure to carry current?

In exactly the same way as your quote at the top, what convincing evidence do your have for us of
It is in all honesty VERY difficult to get electrocuted even if something is wired so horribly wrong as to make it relatively dangerous.
Is the case so clear cut that an absolute dividing line may be placed? "This circuit will knock you unconscious, but it will never be fatal" - "this circuit will kill you every time".

I think it's more than hard to make such distinctions. While most of us in the field have been shocked, it really does not support your position on how hard it is to die from electrocution. One is always better off not making contact with charged wires.
 

sceadwian

Joined Jun 1, 2009
499
It's not really an attitude Beenthere, it's a straight up simple question based on logic and information. I can understand a company wanting to keep a particular unit simple to keep costs low which is why units like this exist in the first place, they obviously sell them, I have not to this point seen any documented case of a lethal shock occurring through their use, or even accidental shock, although there must be some out there more than likely from an improper installation I have not been able to find anything other than hearsay using Google. While that is not definitive proof that no such evidence exists it really leaves people that say these devices are irrational in their use with some need for a burden of proof for the application.

Every electrified building in the known world has outlets less than a few mm's of distance between you and a conductor capable of delivering dozens or more amps. I don't see people panicing bout electrical outlets though, even in a bathroom right over a sink, ground fault interupters are usually found in bathrooms but that won't protect from a live neutral fault (electrocution) the risk is still there, it's all around us and it's horribly lethal... under the right circumstances. Risk is quantifiable this is why there are insurance companies =) Actually that might be a good avenue for further research is insurance claims or what not associated with these devices.

How likely does that sound? How does the wet environment affect the hazard? Is there any corroboration to the use of the structure to carry current?
In exactly the same way as your quote at the top, what convincing evidence do your have for us of
How does a wet environment effect the hazard? Why would you even ask that question, if you know what electricity is and can do the dangers of a wet environment are apparent. The case of an electrified hot water shower while it is a wet environment is a special case because there is an air gap between the conductor and the water, aside from whatever capacitive storage the surface of the water droplets have there is no charge transfer possible except in very specific cases that are difficult to produce, much like sticking a fork in an electrical outlet (there are documented lethalities concerning that)

You want proof? Take a shower using one of these heated showerheads, it's distance from your body should be relegated to 6 inches at all times. Now pick up an electrical plug with your hand and plug it into the wall. You just came at least 10 times closer to being near a live voltage source than in that shower.

Let me make it perfectly clear that I'm not trying to support the selling or use of these devices for anything except an overhead shower if they're not fully insulated. But the risk associated must be analyzed or it's nothing but paranoia.
 

beenthere

Joined Apr 20, 2004
15,819
The question about running AC through a steel framework is from sheer disbelief. That steel has to conduct pretty well to ground - wet environment insures it. Having spent years aboard a cruiser and having made electrofishing boxes for the state, I have a pretty good idea of what constitutes a "wet environment". All your power has to be isolated from the hull (read steel framework) or the real meaning of short circuit becomes obvious.

Interestingly enough, the test for the ship's electrical output was to pass current between electrodes in a tank of salt water. The quantity of water that evaporated in one hour was used to make the calculation.
 

sceadwian

Joined Jun 1, 2009
499
Beenthere, your preconception is based on your experience which is why you can't believe it could occur; an industrial environment is not a ship. On a ship ANY exposed metal surface is ground, your entire environment is de facto grounded.

Light industrial/manufactoring environments are by large and far brick walls and concrete floors, often bare. The steel structure anchored into a concrete floor will have no good ground, unless it is explicitly supplied one.

http://www.cement.org/bookstore/profile.asp?id=891

In short is says 'moist' concrete has 10k ohms of resistance per centimeter and oven dried concrete has like 10GIG ohms per centimeter of resistance. Even in what I consider a 'wet' environment there was a good 100k ohms to the nearest ground, even touching a live conductor. Most of the shocks were more than likely due to human body capacitance and internal current flows between the different potential points, basically self grounding because of the internal phase shift.
 

beenthere

Joined Apr 20, 2004
15,819
This has diverged quite a distance form the danger presented by that tankless water heater.

Light industrial/manufactoring environments are by large and far brick walls and concrete floors, often bare. The steel structure anchored into a concrete floor will have no good ground, unless it is explicitly supplied one.
Is your point that running power along steel framing is:
1. possible?
2. desirable?
3. interesting to argue about?
4. entirely reasonable to use?

We do try to give some emphasis to safety by urging avoidance of exposed conductors unless a meter can demonstrate no or safe voltage levels. Taking the position that coming in contact with a live conductor while on concrete because standing on a concrete floor somehow confers perfect safety is unreasonable.

A shock is a nasty occurrence. Even is not likely to result in a fatality, one is always better practicing safe habits. So standing in water with a live conductor immediately overhead (not to mention the shower control handle) is to be avoided. So is running power along surfaces that can't be properly insulated.
 

sceadwian

Joined Jun 1, 2009
499
1. yes.
2 3 and 4. No, where those came from I'm not even sure.

It's a relative comparison of risk. I trust the electrician that told me of the steel frame being connected to live, the had no reason to lie, it was just THAT bad of a situation, he's the one that fixed it.

I've also used a grinder that was plugged into a miswired outlet (polarized plug, no ground and it was wired backwards) and it's housing was live to the same effect.

The nearness of electrical outlets is DIRECTLY portent to the conversation at hand, that a live heating element in an overhead shower is not death waiting to happen, there are greater risks in your immediate environment, and most of them are from stupid people that you have no control over in the first place.

Taking the position that coming in contact with a live conductor while on concrete because standing on a concrete floor somehow confers perfect safety is unreasonable.
I agree 100%, I didn't say such a thing, the value's I listed were from a noted study. Their values of resistance are calculated from the known environment, and if such measures can be guaranteed to remain in effect non-lethal current flow can be guaranteed not to occur. This is not 100% saftey, there are an unknown number of additional grounds from any given circumstance, but general satety risk can be calculated under known conditions.
 

Wendy

Joined Mar 24, 2008
22,368
I believe I did mention a fatality, in the form of that soldier that was electrocuted earlier this year (or was it last). When a device is so obviously unsafe, does someone have to die to be attended too? This ain't rocket science, it ain't even electronics, it's just basic electricity.
 

Norfindel

Joined Mar 6, 2008
326
Tell me, if the heater is in direct contact, what happends if you rise your hand and touch the water that is coming out of it directly? There's no air gap then. Even more, how does this not electrify all the house's water lines?
 

retched

Joined Dec 5, 2009
5,208
Because. Thats why. ;)

But honestly, I think this is a horrible idea, and I am almost embarrassed to see some people say "Google doesn't show that It has killed anyone, so it's safe!"

Bad idea. I wouldnt want my kid brushing their teeth or washing their hands from a sink while this is being used in a shower.
 
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legac

Joined May 4, 2005
54
I know many fatal cases from using this direct heater. If you want to make a tourist tour, please make sure that your room are not equiped with this fatal boiler.
 
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