Electric Shock from bad water heater element

[jmsokol]

Does such a device exist? If anyone has a lead on it, please post the link.

Sadly, this product doens't exist. I'll be glad to talk to Progressive or any other manfacturer at the Hershey RV show next month. Just give me a heads-up.

Mike Sokol
mike@noshockzone.org

 

[evolvingpowercat]

Thanks jmsokol for your excellent post. I have edited my prior post and removed the ground rod mitigation suggestion based on your and others stating that is not a valid solution.

The saftey ground for an RV having to go thru portable cords and several plug/socket connections to reach the ground bonding point in the service panel or generator if dry camping is a reliability concern to me. So I always manually test with a tester like I posted a photo of earlier in this thread when I connect.

Do you think RVIA should require a lighted and audible warning if power is applied to the shore power connector without a good saftey ground ? One would think this could be designed into RV shore power outlets, or into RV electrical service boxes with reasonable cost, the incremental cost should be well under $ 50 with scale. Are you aware of any RV saftey products of this type that are already available for retro-fit?

> Now not withstanding the previous post about 3 volts being dangerous, I suspect he meant 30 volts as that's the generally accepted minimun electrocution voltage. However, one brief word about using the word "electrocution". To say that you're "electrocuted" actually means you were killed by electrical voltage. You can be "shocked" and not killed, but you can't be "electrocuted" and still be alive.

Reference: Conduction of Electrical Current to and Through the Human Body: A Review http://www.eplasty.com/index.php?opt...9-eplasty-2009

The medical journal article I referenced earlier in this thread said "worst case" body with wet skin completing an electrical circuit could be lethal at 3 volts AC as the resistance path of the person with wet skin worst case is about 300 ohms, allowing 10 mA to flow across the body. The thread started with soaking wet people with bare feet getting a very major shock when entering a RV, so that was the use case I was adressing. The article was very good about documenting how little electrical voltage it takes to shock or harm a person with wet skin making the electrical connection across their body.

The article also stated experiments show some people with wet skin can "feel" current at as little as 0.1 volts, I scaled that to 0.3 volts as a more reasonable voltage to measure.

Given the shock was from trailer to earth next to the trailer, a secondary ground rod next to the trailer would seem to be the way to mitigate that threat for wet barefoot people in particular under all circumstances, one would still be protected even if the saftey ground back to the service panel failed or started to have higher than normal resistance with all of those portable cords and plug/socket connectors in it. I stated "have an licensed electrician do it" because of all the details I am not familar with like the one you mentioned where the secondary ground rods MUST be bonded with proper size ground wire to the primary service panel ground rod.

 

[jmsokol]

Do you think RVIA should require a lighted and audible warning if power is applied to the shore power connector without a good saftey ground ? One would think this could be designed into RV shore power outlets, or into RV electrical service boxes with reasonable cost, the incremental cost should be well under $ 50 with scale. Are you aware of any RV saftey products of this type that are already available for retro-fit?

I've talked to the RVIA and RVDA about this sort of thing, and nobody at either organization wants to do anything that would A) add to the cost of an RV which could stop a sale, or B) educate the public about testing for electrical safety since they think it will scare away potential buyers. Yes, it's frustrating, but if enough of you keep asking your RV dealerships about it, perhaps somebody will listen.

I've been consulting with every major test gear manufacturer from Fluke, Triplett, Extech, Ideal, Amprobe, and others about adding RPBG (hot-ground) sensing to their testers, and few of them admitted that the condition could even exist until I showed them my RPBG schematics and demonstration videos, and they repeated the experiments for themselves. Everyone assumes that an outlet will be wired correctly and that it was inspected properly, but in the real world (especially campgrounds and garage outlets) there's rarely any real technical training for the guys doing the wiring. I've consulted on a number of incidents where a licensed electrician accidentally wired an outlet with an RPBG, which then blew up a bunch of sound gear. They came back and retested with a 3-light tester and declared there was nothing wrong with the outlet, but measuring from a cold-water pipe to the ground pin on the outlet showed 120 volts.

More on this later, but I'm trying to put together a national education program about electrical safety around RV's, boat docks with power, homes and business power, and pet safety. I'll keep you posted via updates on www.NoShockZone.org.

Mike Sokol

 

[evolvingpowercat]

Mike, thanks so much for adding to this thread.

Think everyone with an RV should take your advice and get a Non-contact tester to enable them to be able to check for hot skin condition and to check for mis-wired receptacles. I just did!

 

[jmsokol]

> Now not withstanding the previous post about 3 volts being dangerous, I suspect he meant 30 volts as that's the generally accepted minimun electrocution voltage. However, one brief word about using the word "electrocution". To say that you're "electrocuted" actually means you were killed by electrical voltage. You can be "shocked" and not killed, but you can't be "electrocuted" and still be alive.

Reference: Conduction of Electrical Current to and Through the Human Body: A Review http://www.eplasty.com/index.php?opt...9-eplasty-2009

The medical journal article I referenced earlier in this thread said "worst case" body with wet skin completing an electrical circuit could be lethal at 3 volts AC as the resistance path of the person with wet skin worst case is about 300 ohms, allowing 10 mA to flow across the body. The thread started with soaking wet people with bare feet getting a very major shock when entering a RV, so that was the use case I was adressing. The article was very good about documenting how little electrical voltage it takes to shock or harm a person with wet skin making the electrical connection across their body.

The article also stated experiments show some people with wet skin can "feel" current at as little as 0.1 volts, I scaled that to 0.3 volts as a more reasonable voltage to measure.

You're correct from a strictly medical experiment point of view, but both the NFPA 70E (National Electrical Code) and the ARRL (Amateur Radio Relay League) consider the human body's hand-to-hand resistance (under wet conditions) to be between 1,000 and 1,500 ohms, and 30 mA of current across the chest cavity is considered to be nearly 100% certain to start Atrial Fibrillation. The industry accepted low threshold for heart failure brought on 60 Hz AC is 30 volts but if you break the skin barrier or place electrodes close to your heart, it could go into fibrillation at 5 mA or less, but that's really hard to do. That's why GFCI (Ground Fault Circuit Interrupters) are set with a 5 mA to 6 mA tripping threshold.

And certainly if you cut through your skin and touch a nerve with anything even close to 1 volt, you will feel it. Try touching a 9-volt battery to your tongue for a real eye-opener.... (no, it's not dangerous). But it's the heart itself we need to protect from low-voltage (under 600 volt) shocks.

Interestingly, it's DC current at hundreds of volts that's used to restart a heart in Fibrillation (called De-Fibrillation) and that's what happens when the medic yells "clear" and they hit the button. A big surge of DC current is used to reboot your heart and stop if from quivering uncontrollably during an Atrial Fibrillation event.

Most of this I know from my Electrical Engineering training (I was a controls designer and IE for Corning, and used to build Nuclear Missile Guidance Systems back in my youth plus had my Master Electrician's License since 1978), but I've also done a lot of shock experiments on my own, sometimes unintentionally. I was accidentally shocked hand-to-hand with 650 Volts DC, and knocked myself out due to rebooting my heart. And I've had some pretty serious AC shocks in my youth. I just don't want any of you to have to experience that sort of thing (or even worse).

Keep me posted and I'll do my best to help.

Mike Sokol
mike@noshockzone.org

 

[JohnDar]

Closest thing I know of to test for the presence of A/C voltage without touching it is this thing. We use it whenever we need to determine if a wire is energized. Also use it to determine the charged area around a downed line on the ground or if a vehicle hits a pole and wires are draped on it. These run around $300, though.

http://www.hotstickusa.com/products/achs/ACHotStick_DataSheet_English.pdf

 

[evolvingpowercat]

> the NFPA 70E (National Electrical Code) and the ARRL (Amateur Radio Relay League) consider the human body's hand-to-hand resistance (under wet conditions) to be between 1,000 and 1,500 ohms, and 30 mA of current across the chest cavity is considered to be nearly 100% certain to start Atrial Fibrillation. The industry accepted low threshold for heart failure brought on 60 Hz AC is 30 volts but if you break the skin barrier or place electrodes close to your heart, it could go into fibrillation at 5 mA or less, but that's really hard to do. That's why GFCI (Ground Fault Circuit Interrupters) are set with a 5 mA to 6 mA tripping threshold.

Thanks I agree with you - the medical researcher actually had people standing in two buckets of water to create the worst case scenario with only 300 ohms resistance in the current flow path. His research results reported in the paper match your statements in terms of more typicaly "hand touching hot RV skin" scenarios.

 

[evolvingpowercat]

Mike, thanks so much for adding to this thread.

Think everyone with an RV should take your advice and get a Non-contact tester to enable them to be able to check for hot skin condition and to check for mis-wired receptacles. I just did!

I got a non-contact tester with adjustable threshold. Home Depot, Lowes, and Ace Hardware don't sell the Fluke kind that Mike recommended, so I got another kind with threshold adjustable between 12 V and 600 V. I just want to know that those that are not "technical" if you buy this "adjustable" kind, you have to "learn" how to use it, so that you don't freak out from false positives.

Personally, I was able to adjust it using a known good 110 Volt receptacle. Mike, this might be another how-to for your youtube collection

Another note, when doing the hot skin test with the adjustable kind like I purchased. It will sense wires in the trailer wall with its sensitivity turned up this is not hot skin. That's one of the things its made for is to warn you if there are live wires in a wall that you are about to start cutting or drilling holes into.

If it beeps on the step or touchng the door handle that's bad. If it beeps with the sensitivity turned up when held near the outdoor outlet most Heartland RV have somewhere not too far from the door that is very likely not bad.

 

[jmsokol]

I got a non-contact tester with adjustable threshold. Home Depot, Lowes, and Ace Hardware don't sell the Fluke kind that Mike recommended, so I got another kind with threshold adjustable between 12 V and 600 V. I just want to know that those that are not "technical" if you buy this "adjustable" kind, you have to "learn" how to use it, so that you don't freak out from false positives.

Personally, I was able to adjust it using a known good 110 Volt receptacle. Mike, this might be another how-to for your youtube collection

Another note, when doing the hot skin test with the adjustable kind like I purchased. It will sense wires in the trailer wall with its sensitivity turned up this is not hot skin. That's one of the things its made for is to warn you if there are live wires in a wall that you are about to start cutting or drilling holes into.

If it beeps on the step or touchng the door handle that's bad. If it beeps with the sensitivity turned up when held near the outdoor outlet most Heartland RV have somewhere not too far from the door that is very likely not bad.

Yes, those adjustable ones work as well, but you do have to "calibrate" them against a known voltage source such as a 120 volt outlet. They should beep in the "hot" slot (short one) and not beep in the "neutral slot (tall one), and of course it should not beep in the ground slot. It's possible to get the threshold set so low that they beep anywhere near the front of an energized outlet, which does produce a "freak-out" effect from first-time users. You do have to use a known-good outlet for this calibration test, but any modern home outlet "should" be fine.

Mike

 

[wdk450]

In all of the discussion of possible causes of hot trailer skins, we know we don't want this to happen, but if it DOES happen. won't a GFI at the connection point detect the imbalance of current flow in ANY of these situations if a shock occurs and cut the power, thus stopping the electroshock accident???

 

[jmsokol]

Closest thing I know of to test for the presence of A/C voltage without touching it is this thing. We use it whenever we need to determine if a wire is energized. Also use it to determine the charged area around a downed line on the ground or if a vehicle hits a pole and wires are draped on it. These run around $300, though.

http://www.hotstickusa.com/products/achs/ACHotStick_DataSheet_English.pdf

Well, the Fluke VoltAlert (which costs $25 and rated from 90 to 1,000 volts) will beep like crazy about 18 inches away from an RV with its body hot-skin energized to 120 volts. If you don't believe it, watch this video of me energizing a 40 ft toyhauler up to 120 volts: http://www.youtube.com/watch?v=Y8h64X33aKg&feature=plcp Once the RV skin is down to 40 volts you'll need to bring the probe tip close to the surface or actually touch the RV with it, but it's a proximity thing as it doesn't care about paint or rust like a standard volt meter with probes does. This experiment is done with a custom kludge cable I built myself and a B&K Precision AC power supply, which allows repeatability of testing with various voltages and NCVT's (Non Contact Voltage Testers). It's a perfectly safe experiment for the RV itself, but of course deadly to anybody sneaking up behind the RV and touching anything metal, so I only do this type of demonstration inside where I can control access to the RV. The tow vehicle is also energized with a 120-volt hot-skin and could kill somebody grabbing the door handle to jump in.

If you want a tester with a longer reach (40 inches) and adjustable sensitivity (down to 5 volts) the Extech DV-50 works very well for less than $50. See http://www.extech.com/instruments/product.asp?catid=31&prodid=520. We're experimenting with this product around boat docks checking for energized conduit and electrical boxes as well as electrified boat shore power connections. There's a voltage gradient effect that reaches out dozens of feet from an improperly grounded boat which can paralyze swimmers and drown them with no sign of electrocution. Don't swim around boat docks with electrical outlets or house boats plugged into shore power. That's what killed those 3 kids this summer swimming between house boats.

 

[jmsokol]

In all of the discussion of possible causes of hot trailer skins, we know we don't want this to happen, but if it DOES happen. won't a GFCI at the connection point detect the imbalance of current flow in ANY of these situations if a shock occurs and cut the power, thus stopping the electroshock accident???

GFCI's are only on the 20 amp pedestal outlet, not on the 30 or 50 amp outlets since there's too much stray leakage current that will cause random tripping (and your fridge going off). Also remember that if you're plugged into a RPBG (Reverse Polarity Bootleg Ground) outlet, that the current flow isn't detected by the GFCI circuity and won't trip. Even if it DOES trip for some other reason, it won't disconnect the hot ground from your shore power connection, creating a hot-skin condition where all the circuit breakers turned off. See http://www.noshockzone.org/rv-electrical-safety-part-viii-gfci/ for an article I wrote about GFCI theory.

Interesting, isn't it?

Mike

 

[jimtoo]

Mike,

I have a Gardner Bender (GVD-3505) Live Wire Tester. I purchased it a while back when someone else suggested using this to trace wiring without contact. I have found that it works really good. No contact is needed, you can check the plug and anything from 12v to 600v AC.
What is your opinion on this for someone to carry and use to check the campground box or connector? I know it would not be something to carry after hookup and going swimming,, but to check things before and after the initial setup.

Jim M

Wish the OP would come back and answer my questions so we could know a little more about when and how.

 

[jmsokol]

The Gardner Bender (GVD-3505) Live Wire Tester should do the job as well, as long as you know where to slide the sensitivity switch so that it doesn't trigger on everything. Usually the 12-volt setting is too sensitive for testing outlet polarity before plugging in, but the lowest threshold (highest sensitivity) is good for checking hot-skin conditions. Remember, according to National Electrical Code, there should be no more than 3 volts between the earth ground and the chassis/skin of your RV. In reality, it should be much lower than that if you have a solid low-impedance connection back to earth, but there could be induced voltage drops caused by other RV pedestals around the campgrounds. Any more than a few volts is cause for concern. So your 5 volt test should be pretty spot on. Note that I've not personally used the GB tester you mention, so I can only guess at its actual voltage thresholds. But I would be glad to do a calibrated test if someone at Gardner Bender would send me a sample.

Don't think that I'm fishing for a free tester because I can't afford one. I have dozens of them on my test bench already. But I'm always willing to talk to manufacturers about their products.

Mike

 

[evolvingpowercat]

FYI, the kind I bought at Ace Hardware today was a Sperry Instruments VD6505, there were cheaper ones on the wall too but I liked seeing all the certifications on the packaging that were not on the cheaper ones.

 

[jmsokol]

FYI, the kind I bought at Ace Hardware today was a Sperry Instruments VD6505, there were cheaper ones on the wall too but I liked seeing all the certifications on the packaging that were not on the cheaper ones.

Looks like a good choice. I'm sure you know this, but for many of the non-technical members on this forum, it's generally not a good idea to go cheap with test gear, especially if it's going to be used around high-voltage or high-current situations. Really well built test gear will survive all sorts of voltage spikes and such, but cheap gear has a tendency to blow up in your hands on occasion. There's something call an Arc-Flash which is more terrifying than being knocked unconscious by a big shock. I won't go into it here, but that's why you see electricians at power sub-stations running around in what appear to be space suits.

Mike Sokol

 

[porthole]

So, Mike, glad you came back on forum with this. I was out all day and had planned on linking the previous thread where you went over all this in the same depth.

Those original posts hit home as several years ago I leaned on our dog pen at camp and got zapped. No wonder the pups were not jumping that weekend. We disconnected and left.

After your last series, I orderd up the Fluke Volt alert and use it every time, thanks!

For those looking for the Fluke tester, it s readily available on eBay or amazon. Got mine for $21 delivered.

Closest thing I know of to test for the presence of A/C voltage without touching it is this thing. We use it whenever we need to determine if a wire is energized. Also use it to determine the charged area around a downed line on the ground or if a vehicle hits a pole and wires are draped on it. These run around $300, though.

http://www.hotstickusa.com/products/achs/ACHotStick_DataSheet_English.pdf

Hey John, we use a special tool also.
When the lineman holds both ends in each hand, I figure it is safe to approach.

 

[JohnDar]

So, Mike, glad you came back on forum with this. I was out all day and had planned on linking the previous thread where you went over all this in the same depth.

Those original posts hit home as several years ago I leaned on our dog pen at camp and got zapped. No wonder the pups were not jumping that weekend. We disconnected and left.

After your last series, I orderd up the Fluke Volt alert and use it every time, thanks!

For those looking for the Fluke tester, it s readily available on eBay or amazon. Got mine for $21 delivered.




Hey John, we use a special tool also.
When the lineman holds both ends in each hand, I figure it is safe to approach.

Do the blue sparks between his teeth indicate not so safe?

 

[jmsokol]

Everybody....

Thanks for all your input so far. I learn a lot about the state of the RV industry by trolling these forums. As you can see, I have a lot of time and knowledge invested in understanding and writing about electrical safety. But I'm working on a nationwide teaching program that I hope to get a training grant for that will fund these efforts. So I need your help with spreading the knowledge that RV electrical safety is serious business, and that everyone needs to take charge of their own safety. Please send a link to this thread to anybody you know with an RV and let them know you plan to observe these basic safety principals. And go ahead and tell your Heartland rep and dealer that you would like to see more training for both the public and RV technicians on how to test RVs and their power sources for voltage, grounding and hot-skin conditions.

I'm only one guy doing this as a side gig (yes, I have full time job as a technical writer and seminar instructor for music mixing), so it's hard for me to spend as much time as needed to teach everybody. That's why I only show up on specific forums occasionally. Once I'm done here for now, I'll find another interesting thread somewhere else that needs my help and work on that for a day or two, and so on... However, with proper industry and grant support I could really attack the problem of improperly wired campgrounds and RVs and save a lot of lives.

Thanks very much for your support, and keep those comments and questions coming.

Mike Sokol
mike@noshockzone.org
www.noshockzone.org

 

[jbeletti]

Sadly, this product doens't exist. I'll be glad to talk to Progressive or any other manfacturer at the Hershey RV show next month. Just give me a heads-up.

Mike Sokol
mike@noshockzone.org

Mike - will you have a booth?