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Safety: How hazardous can a 14s be to your life?
treat it as if it is live.
keep 1 hand in your pocket just like you should with any live equipment.
getting hit is bad enough.
getting hit via a path through your heart is deadly.
i work on lots of hv dc stuff.
600v dc bus for vfd units (industrial motor drivers),plate supplies for rf power amplifiers(linears),ect.
Korishan likes this post
I asked for what the limit was to work on in the Netherlands: it is still below 62v without papers above you are not allowed to do anything without papers.
But even with dry hands....48v and a 50kwh battery touching both terminals....nah i believe you, in everything you are saying, i am not going to try, or find out.
Put fuses everywhere and be safe please.
Look into one of the videos of this forum founder: hb powerwall.
He had a small mistake with one of his batteries.....
Can not remember exactly which one, but it was a huge spark...we all make mistakes, but we don't say or show.

Back in school they always taught me to touch after you make sure everything was safe, with the back of your hand.
And be careful with those thick and long wires cause they could act like a capacitor.
When talking about 10kv lines ac or bigger in those transformer houses, always after shutdown and after the discharge cable throw your rat to the coils...
Was 30 years ago when they tried to teach me something Rolleyes, i suspect there are now some sophisticated measurement devices?
I am just curious, sorry

Thanks in advance.

I think most of you are being overly dramatic.

You'd just about have to try to be injured with anything 50V or lower on AC, let alone DC. Most countries don't even have regulations for anything below 50v.

Most of the time, you could grab 120vdc and it would hurt a bit, but you'd be alright.

AC is far more dangerous than DC because of your body's capacitive coupling.

Do you guys know ElectroBoom? Here's him hooking up 10 car batteries in series (123vdc) and touching it. He gets surprised at first that he can even feel it, but he can touch it without problem. And he's a sweaty kind of guy.

Protect it if you want, but, I wouldn't be overly worried.
Wet skin, especially sweaty skin, can and will conduct more current than dry skin. If dry skin and touching 60VDC both lines, then the chances of getting electrocuted is very very low. DC current must "punch" through the skin to the deeper more conductive tissue before it can flow. AC current doesn't need to do this, so lower AC voltage can allow current to flow sooner.
However, at 120VDC wet and especially sweaty skin, current will be able to penetrate the skin and conduct a short circuit through your body. Whether that path goes through your heart or not will determine if you live through the process. Also, duration is a factor. If you let go soon enough, no harm.
120VDC will have a much harder time penetrating callused skin than thinner skin. As Matt is referencing ElectroBoom (whom I find to be very annoying, imho), his hands are not exactly soft. He's got rough hands. Maybe this is why it didn't effect him. I bet if he put the wires under his arm pits, he'd get a nice hot spot if not a burn mark.

We here on SLS in no way advocate or downplay the safety factor of voltage and current. It only takes 2mA of current to kill a person. A single 18650 cell can deliver that much current. However, it's voltage can't penetrate. Scale the voltage up with series connections, and even a 1p setup, could make for a very bad day for someone.
Safety is primary above ALL other things. I personally have been bit by 12VDC, so I "know" that higher voltages has the potential of doing damage if the conditions are right. ALWAYS work with electrical connections with dried hands. NEVER work with wet or sweaty hands. It only takes a slip up to get bit, especially at the higher voltages.

Are we being overly dramatic? Maybe. Are we being cautious so we don't get electrocuted? Most definitely. Electricity has the potential to kill, and kill "very" rapidly if not treated with respect, and this doesn't matter if it's AC or DC.
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Quote:As Matt is referencing ElectroBoom (whom I find to be very annoying, imho), his hands are not exactly soft. He's got rough hands.

Medhi's hands are both abnormally soft and sweaty. I mean, I wasn't on stage touching him during the presentation, so perhaps he made special efforts to dry them, but it was his first public appearance and he was nervous as hell.

He is (well, was, before being a content creator) an engineer, not a welder or fabricator.

Quote:It only takes 2mA of current to kill a person. A single 18650 cell can deliver that much current.

Err, suppose that's true, that's still a bit like saying "The world's Strongman winner can lift a paperclip!".

A single 18650 can deliver 20,000x the amount of current required to kill you.

But... 2mA is not a realistic estimate.

See here:

Below 500mA, (250x your lethal minimum) effects are reversible for short shocks. Lowest that's fatal is still 15x your minimum, at 30mA. 2mA isn't debateably even reaching the threshold of sensation yet, let alone lethality.

It's common in developing countries to have bad grounds on half your appliances, such that you get zapped a little when you touch them.

However, these are all still practically microscopic amounts to anything a human will encounter. Almost every piece of electronics and every power source ever made aside from maybe the solar cell on your calculator can deliver enough current to murder you.

It's almost not worth talking about current, only voltage.

And yes, most everything else you said is correct.

Even if the odds are 1 in a million, (that poor sap who died from 42vac) you don't want to be the lottery winner. So, to someone who has to ask, the answer to behavior I suppose should almost always be to treat electricity like a loaded firearm. Safety safety safety, use no judgment, make no assumptions, do the safest thing.

But for a reasonable person in most reasonable circumstances, you won't even feel voltage below 50vdc. The world record for fatality, is 42vac. If you keep a consistent level of paranoia (with respect to consistent odds of a behavior being fatal) of your behaviors across all aspects of danger in your life, there are thousands of everyday things you should be avoiding before you should be scared of voltages below 50vdc. Never play a sport. Never move faster than a walk. Never go outside. Never enter a car. Never walk down a street. Never sip a beer. Etc.

Quote:We here on SLS in no way advocate or downplay the safety factor of voltage and current.

Genuine question...

Does SLS even have an official voice with the authority as to what "we" advocate or not? I'm not familiar.

My perception is that this is a community, and thus makes no official claims of safety, danger, endorsement, condemnation, or other opinion. It's just a group of people with their own opinions. Bit of a slippery slope to start making official representations of authority on anything, safety or otherwise, lest anyone miss moderating a comment and then be held responsible for the content of what was said unchecked.
I dont know what rules in most country's, but here in the Netherlands is max62vdc without papers.
After the ac fuse box you are allowed to do the installation yourself, everything is at your own risk, but it is allowed to do yourself, above 400v ac nope.
I has a lot to do with the individual as well, I can sometimes feel the effect of a 12v battery, while friends can’t. This is mainly due to the individuals skin resistance and moisture, salt levels and the amount of dead skin.
Dead skin is also a reasonable insulator compared to muscle and nerves.
What really needs to be taken into account is the voltage and resistance of the body and where it’s being applied, dry skin has a typical resistance of approx 100,000 ohms, wet new skin is approx 1000 ohms, the amount of distance between where the voltage is applied also plays an effect, as well as men having a lower resistance then women too.
A 3.7v battery touching dry skin could cause a current flow of approx 3.7/100,000 = 0.037mA , the same on wet skin is 3.7/1000=3.7mA, however skins dielectric effect also comes into play with DC as mentioned above and negates most of this. There’s lots of variation in all of this of course. Best to be careful over 50v, especially if you have hands that are wet or with soft supple skin Smile
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