Hwy89
10 kW
Remember to remove remove rings, jewelry, piercings, etc.
72V electrocution?
- Thread starter le15otl
- Start date
le15otl
100 W
Interesting and helpful points. Reason i'm concerned isn't really for working on the bike buy using as i usually have the battery in a backpack with a wire down to the bike and the XT90 is kind of open contacts when unplugged.
I'm reassured by the info here but will be careful nonetheless. I just can't imagine how liveforphysics you've taken 100v hand to hand so damn frequently
I guess greasey hands is another way that could increase the risk...
I'm reassured by the info here but will be careful nonetheless. I just can't imagine how liveforphysics you've taken 100v hand to hand so damn frequently
I guess greasey hands is another way that could increase the risk...
wesnewell
100 GW
Ask any telephone man how many times they've been zapped with 90-100VAC ring current from the CO. I'm sure I've been zapped at least several hundred times. You never feel the normal 48VDC on the lines, but the ring current will wake you up and make you jump fast.
le15otl
100 W
Hmm I see that some people including yourself do have higher tolerance to a shock. I guess I just don't know how resistant my skin is. ..
Might check it with the multimeter hahaha
Despite your demo video I can't bring myself to bite my teeth and touch the terminals..
Also i guess everyone's heart has different tolerances ? although I've had plenty of electric fence shocks I haven't had a 220v mains shock .
Might check it with the multimeter hahaha
Despite your demo video I can't bring myself to bite my teeth and touch the terminals..
Also i guess everyone's heart has different tolerances ? although I've had plenty of electric fence shocks I haven't had a 220v mains shock .
I've been shocked by120VAC countless times. 240VAC maybe a dozen times. Like the other posts say, if your not dripping with sweat or
standing in water or something, it's usually gonna be just a good scare.
You should be extremely careful around 220-240AC mains, I've never met anyone that brags about playing careless with it.
As for DC voltages in the 50 to 100V range. I imagine a lot of technicians that work in the field would laugh at this thread
because they get shocked on an almost daily basis.
Nevertheless it's always good to be careful if you're not sure, or if toddlers might get access to the wiring.
A bigger danger is flash burns if you accidentally short something. We have lots of KFF pictures where this happened.
I wouldn't worry about the wires from a backpack battery at all. I would worry about the cells in the backpack, especially in a crash.
I wouldn't worry about the wires from a backpack battery at all. I would worry about the cells in the backpack, especially in a crash.
You can probably find a different set of plugs that would make you feel more at ease, then if you tinker
with the other wiring just unplug the battery.
http://www.ebay.com/itm/1-Sets-AC-250V-10A-IEC-320-C14-Male-Plug-to-C13-Female-Socket-Power-Connector-/141693054659?hash=item20fd906ec3:g:xmMAAOSweW5VfbKe
If you ever have to troubleshoot something with the battery connected, wear some inexpensive latex gloves.
They should offer enough protection for that system voltage if you're really nervous about a random shock.
liveforphysics
100 TW
Eteck said:
240v once stopped my heart for a few seconds (which feels like a few minutes when your heart stops). It restarted on it's own and overall the experience was fine aside from my chest muscles and biceps feeling a bit torn up.
I don't recomend taking shocks above ~150VDC or 110VAC to anyone for any reason if avoidable (and it generally is).
Also do not wear any conductive jewelry. You think you could easily get a ring off your finger if it were hot, but EV batteries can make it glowing brilliant orange hot in the blink of an eye. At this point you will have preferred that you had removed it while you still had the opportunity to do so at room temperature.
I should add, no reason for any ebike to be above 20s if purpose-built design intent is hot rod performance.
molybdenum
1 kW
In the vast majority of cases, a shock from an ebike battery would not lead to electrocution and the risk is very low, but if the right conditions are met, the outcome could be lethal.
The pacemaker cells in the heart transmit the signal to coordinate their contractions with a current on the order of ~20 mA. For this reason, it's the current that kills, while voltage and skin resistance determine the current the heart is subject to. While any amount of current through the body over 10 mA (0.01 amp) can produce painful to severe shock, AC currents as low as 30 mA but typically between 100 and 200 mA (0.1 to 0.2 amp) passing through the chest are often lethal; these currents disrupt the normal currents the pacemaker cells use to maintain heart rhythm, resulting in fibrillation or the uncoordinated twitching of heart pacemaker cells. While AC currents above 200 mA (0.2 amp) produce severe burns and unconsciousness, they are less lethal. It is thought that these strong currents cause the heart muscles to seize up, protecting the heart from fibrillation. DC currents are thought to be less likely to lead to fibrillation, requiring 300 – 500 mA.
The amps travelling through the chest are determined by skin/tissue resistance and the voltage applied. Skin resistance is non-linear and drops dramatically above 50 V. Other factors such as skin moisture dramatically affect skin resistance. In general, for voltages less than 50, skin resistance may vary from less than 1000 ohms for wet skin to over 100,000 ohms for dry skin. Also, all wetness is not equal. Pure water is completely non conductive, and it's the dissolved salts that imparts conductivity.
The pacemaker cells in the heart transmit the signal to coordinate their contractions with a current on the order of ~20 mA. For this reason, it's the current that kills, while voltage and skin resistance determine the current the heart is subject to. While any amount of current through the body over 10 mA (0.01 amp) can produce painful to severe shock, AC currents as low as 30 mA but typically between 100 and 200 mA (0.1 to 0.2 amp) passing through the chest are often lethal; these currents disrupt the normal currents the pacemaker cells use to maintain heart rhythm, resulting in fibrillation or the uncoordinated twitching of heart pacemaker cells. While AC currents above 200 mA (0.2 amp) produce severe burns and unconsciousness, they are less lethal. It is thought that these strong currents cause the heart muscles to seize up, protecting the heart from fibrillation. DC currents are thought to be less likely to lead to fibrillation, requiring 300 – 500 mA.
The amps travelling through the chest are determined by skin/tissue resistance and the voltage applied. Skin resistance is non-linear and drops dramatically above 50 V. Other factors such as skin moisture dramatically affect skin resistance. In general, for voltages less than 50, skin resistance may vary from less than 1000 ohms for wet skin to over 100,000 ohms for dry skin. Also, all wetness is not equal. Pure water is completely non conductive, and it's the dissolved salts that imparts conductivity.
Alan B
100 GW
Latex gloves are very fragile, electrical worker glove systems are a combination of a very heavy rubber glove covered by an outer leather glove. Even a pinhole can allow an arc to blow through the glove, so these gloves require daily inspection and constant vigilance as well as frequent replacement and instrumented retesting. This is primarily due to the high voltage involved.
Clean and dry leather gloves themselves afford a great deal of protection for low voltage work through their electrical resistance and abrasion capacity and are very good against flash burns. Use clean dry leather gloves for low voltage electrical work.
An electrical shock is somewhat like a car accident. Each one is different, and each one has the potential of being very serious, or very minor. It takes only a few milliamps to stop the heart or send it into fibrillation. If it stops it might restart. If it fibrillates it will continue to contract but the rhythm is wrong and blood won't be pumped. Only a short window of time is available to apply a defibrillator before the inadequate blood flow causes major tissue damage and death.
Electrical workers who receive a shock are these days subject to a thorough medical checkup, accident analysis and work planning evaluations. A shock is considered like other workplace accidents that have the potential of easily being fatal. There should be no electrical workers getting shocked frequently, in fact electrical workers, being trained and working with the procedures and tools receive fewer shocks than untrained personnel. Electrical workers are required to test before touching, and energized work is generally not permitted so they should not be getting shocks. Energized work is generally only allowed when there is no way to shut things down, or shutting things down would result in greater safety risk than working live. When energized work is required (such as working on a battery), thorough work planning is required, as is using personal protective equipment including eye and ear protection, insulated gloves and tools, etc. to control the hazards.
Clean and dry leather gloves themselves afford a great deal of protection for low voltage work through their electrical resistance and abrasion capacity and are very good against flash burns. Use clean dry leather gloves for low voltage electrical work.
An electrical shock is somewhat like a car accident. Each one is different, and each one has the potential of being very serious, or very minor. It takes only a few milliamps to stop the heart or send it into fibrillation. If it stops it might restart. If it fibrillates it will continue to contract but the rhythm is wrong and blood won't be pumped. Only a short window of time is available to apply a defibrillator before the inadequate blood flow causes major tissue damage and death.
Electrical workers who receive a shock are these days subject to a thorough medical checkup, accident analysis and work planning evaluations. A shock is considered like other workplace accidents that have the potential of easily being fatal. There should be no electrical workers getting shocked frequently, in fact electrical workers, being trained and working with the procedures and tools receive fewer shocks than untrained personnel. Electrical workers are required to test before touching, and energized work is generally not permitted so they should not be getting shocks. Energized work is generally only allowed when there is no way to shut things down, or shutting things down would result in greater safety risk than working live. When energized work is required (such as working on a battery), thorough work planning is required, as is using personal protective equipment including eye and ear protection, insulated gloves and tools, etc. to control the hazards.
craneplaneguy
10 kW
On a recent off grid solar job I did, I lowered a 1200 lb battery (48 VDC) that I had pre fabbed a rack for in my shop so I could not only transport the 80 miles to the remote job site, but also easily rig and lower it into the underground vault using my crane. The front exposed terminals could not be covered until the installation was complete, and the owner indicated he would do so. He was trying to save money when possible by doing things himself. The negative and positive terminals were 4' apart, but the individual cell connections were a few inches.
Months later, we had the charge controller go out, I climb down into the vault and notice he STILL had not covered the front of the battery, so I pointed out to him in no uncertain terms, that someone not paying attention could get their zipper red hot in an instant, that got his attention. This would have been a situation where the voltage was low, but a huge amount of amps, in a very sensitive location!
Months later, we had the charge controller go out, I climb down into the vault and notice he STILL had not covered the front of the battery, so I pointed out to him in no uncertain terms, that someone not paying attention could get their zipper red hot in an instant, that got his attention. This would have been a situation where the voltage was low, but a huge amount of amps, in a very sensitive location!
Some are, like the ultra thin disposable, others are a little thicker.
OP is not doing professional industrial work with higher AC line voltages,
for OP's worries just about any lightweight dry glove can be used.
The problem with this advice is you lose nimbleness and people will tend to take them off when fidgeting with smaller wiring.
If you're regularly working on large terminal blocks or something, sure sturdy leather gloves might be best.
OP if you have to wear a glove a thicker disposable latex or a thin and dry fabric glove that totally covers the skin would be good.
This usually involves just probing with some meter leads which will not be very abrasive to any glove.
For tearing apart the system the battery can be completely unplugged.
Alan B
100 GW
Leather gloves don't have to be heavy. They can be very flexible and comfortable, and fairly thin. Deerskin or Kangaroo leather gloves can be exceptionally dextrous.
As was pointed out earlier, the biggest risk here isn't shock. It is arc flash plasma damage and burns to the skin. Latex gloves won't protect against that, and if they get melted into the skin the emergency treatment to scrub it out is a terrible process.
Work de-energized when possible. When you MUST work energized, use protection. Safety glasses, gloves as appropriate. Plan your work, keep things covered so inadvertent touches don't conduct. Use insulated tools. Think carefully. If something changes the work stop and re-think the plan to adjust for the new hazards. Most electrical work accidents occur when the work plan is changed in-process without adequate consideration of the new and changed hazards.
Stay Safe.
As was pointed out earlier, the biggest risk here isn't shock. It is arc flash plasma damage and burns to the skin. Latex gloves won't protect against that, and if they get melted into the skin the emergency treatment to scrub it out is a terrible process.
Work de-energized when possible. When you MUST work energized, use protection. Safety glasses, gloves as appropriate. Plan your work, keep things covered so inadvertent touches don't conduct. Use insulated tools. Think carefully. If something changes the work stop and re-think the plan to adjust for the new hazards. Most electrical work accidents occur when the work plan is changed in-process without adequate consideration of the new and changed hazards.
Stay Safe.
Make sure you follow this:
This is good advice. Get rid of any metal jewelry when working on electrical stuff.
But if they're that thin someone will find a problem there even.
A sharp wire will poke thru your thin swede gloves and zap your skin to a low conductive resistance sending 100mA.... SCARY
You guys are bringing up an interesting point, that it's more than just the raw voltage contact that matters.
An arc burn situation can further reduce skin resistance leading to a more dramatic entry of current into the body.
So yes, for the best safety you should find the best gloves available that are still maneuverable enough to actually wear while
working with the wires and connectors. However you are still not really safe, because in a burn situation your arm or some
other part can be involved just as well.
le15otl said:
It's a good idea to get into the habit of only using insulated connectors for the live side of a circuit (usually the male of a male/female pair) so you don't have power present on exposed connector pins when the connectors are apart. It's mainly a shock safety issue for dangerous voltages, but also prevents damage to components on lesser voltage systems.
I have a 84v 20s lipo battery, if i touch the bms when its connected i do get electecuted, but really not so bad, i wasnt even sure it happened so i did it again and it did happend. Not so bad at all. Not pleasent but i can keep on working and even laughing about it afterwards
Safest way to work is with a switch to cut off the current when not needed
I use a 24v 400a killswitch for my 84v 150a system, doesnt even get warm
Safest way to work is with a switch to cut off the current when not needed
I use a 24v 400a killswitch for my 84v 150a system, doesnt even get warm
liveforphysics
100 TW
There is a difference between feeling a shock and being electrocuted, as electrocution implies death occurred.
MrDude_1
100 kW
liveforphysics said:
Reading this, I somehow I get a vision of you charging zero packs with non-insulated alligator clips or something. lol.
I touched most of a Honda hybrid battery when working on it. Probably 120vdc. It got my attention. Stupid mistake when in a hurry. I do take these kinds of voltages seriously.
As a kid, I once touched a 450vdc power supply capacitor in a transmitter. My hand flew back and hit the wall. I had bloody knuckles and was short of breath. Don't want to ever try that again. :wink:
As a kid, I once touched a 450vdc power supply capacitor in a transmitter. My hand flew back and hit the wall. I had bloody knuckles and was short of breath. Don't want to ever try that again. :wink:
Chalo
100 TW
Offroader said:
How bad your shock can be depends on a lot of factors. Dry skin, insulative shoes, circuit doesn't cross your heart-- probably just an annoying little zap. Get really sweaty and touch opposite poles with each hand and you could be dead by the time you hit the floor.
It can easily kill you if you give it a path to ground that passes through your vital organs. Consider that USA standard household electric power has a maximum voltage of about 170V at the top of the waveform, and it's well proven to kill people.
A shock from DC electricity can take away your ability to let go of the thing that shocked you.
dustNbone
10 kW
Yeah 200VDC is firmly in the "can make you dead" zone. I mean most likely it won't. But it wouldn't be surprising to me if it did.
I've never had a noticeable DC shock, but I've been hit by 120VAC hundreds of times and 240VAC maybe a dozen over the years. There's a big difference as far as effect on the body is concerned. 110 is uncomfortable, but once it's over I've never noticed any effects. But a hand to hand 240 jolt hurts, muscles and possibly tendons get damaged from that, it hurts for a little while afterward.
Luckily AC tends to throw you off of it because, well, it alternates. Unless you fall onto it you're probably only in for a brief zap.
DC on the other hand, doesn't do that. If your hand is around something and that thing becomes energized for whatever reason, you will clamp on and potentially not be able to release it.
This is what scares the crap out of me and probably why I've never had a real bad run in with high voltage DC despite lots of messing around with battery packs that make the one on my bike seem not that scary at all.
Matter of fact I've never accidently shorted a tool or anything on a big battery, I'm so damn careful around that stuff because batteries are so inherently unforgiving. When you're working on AC mains and accidentaly short something out, usually a breaker blows. You drop your wrench on a 400V battery you kinda have to let that play itself out. Gonna make a huge mess.
I've never had a noticeable DC shock, but I've been hit by 120VAC hundreds of times and 240VAC maybe a dozen over the years. There's a big difference as far as effect on the body is concerned. 110 is uncomfortable, but once it's over I've never noticed any effects. But a hand to hand 240 jolt hurts, muscles and possibly tendons get damaged from that, it hurts for a little while afterward.
Luckily AC tends to throw you off of it because, well, it alternates. Unless you fall onto it you're probably only in for a brief zap.
DC on the other hand, doesn't do that. If your hand is around something and that thing becomes energized for whatever reason, you will clamp on and potentially not be able to release it.
This is what scares the crap out of me and probably why I've never had a real bad run in with high voltage DC despite lots of messing around with battery packs that make the one on my bike seem not that scary at all.
Matter of fact I've never accidently shorted a tool or anything on a big battery, I'm so damn careful around that stuff because batteries are so inherently unforgiving. When you're working on AC mains and accidentaly short something out, usually a breaker blows. You drop your wrench on a 400V battery you kinda have to let that play itself out. Gonna make a huge mess.
liveforphysics
100 TW
First touch of 200vdc may be your last touch. Likely would survive it though, but it's brutal on your ribs and muscles and joints.
Offroader said:
SirLongAss
100 mW
- Joined
- Aug 26, 2018
- Messages
- 46
72v can and will shock. Although, probably not enough to kill you but certally enough to make you nervous next time you turn on your next circuit.
A few months ago, I received my 72v battery for my ebike with a xt90 discharge connector and a RCA style charge connector. Now when I ordered the only request I made was that the discharge cable has to be an xt90 for my +80a discharges. So I installed the battery and charged it. The first time I connected the two RCA style connectors on the charger and battery, it shocked me(the connector is all metal), enough to make me jump. After that I used gloves to plug it in until one day I forgot to plug in the charger before plugging in the battery in and ZAP! The resulting voltage differential caused the whole connector to burn up. I immediately soldered a xt60 on and havent had a problem since.
TL;DR:
72v can still mess things up in the right conditions.
A few months ago, I received my 72v battery for my ebike with a xt90 discharge connector and a RCA style charge connector. Now when I ordered the only request I made was that the discharge cable has to be an xt90 for my +80a discharges. So I installed the battery and charged it. The first time I connected the two RCA style connectors on the charger and battery, it shocked me(the connector is all metal), enough to make me jump. After that I used gloves to plug it in until one day I forgot to plug in the charger before plugging in the battery in and ZAP! The resulting voltage differential caused the whole connector to burn up. I immediately soldered a xt60 on and havent had a problem since.
TL;DR:
72v can still mess things up in the right conditions.
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