Comments for No~Shock~Zone http://www.noshockzone.org Electrical Safety for Everyone Fri, 09 Mar 2012 02:30:07 +0000 hourly 1 http://wordpress.org/?v=3.3.1 Comment on Stage Electrical Safety — Part 1: Volts by Mike http://www.noshockzone.org/stopping-hums-buzzes-and-shocks-on-stage-%e2%80%94-part-1-volts/#comment-531 Mike Fri, 09 Mar 2012 02:30:07 +0000 http://www.noshockzone.org/?p=549#comment-531 The way I like to explain it to people is that electricity wants to get to the ground, and will always take the path of least resistance to get there. If there is no low resistance path to ground (safety ground through building wiring), and a leak occurs in a piece of equipment, the next person to touch the equipment could easily become part of a new path the electricity takes to reach the ground. Something else worth noting is that if a surge protector is ungrounded, it will not protect against surges. It must have a ground conductor to divert the surge to the ground. The way I like to explain it to people is that electricity wants to get to the ground, and will always take the path of least resistance to get there. If there is no low resistance path to ground (safety ground through building wiring), and a leak occurs in a piece of equipment, the next person to touch the equipment could easily become part of a new path the electricity takes to reach the ground.
Something else worth noting is that if a surge protector is ungrounded, it will not protect against surges. It must have a ground conductor to divert the surge to the ground.

]]> Comment on RV Electrical Safety: Part IV – Hot Skin by Mike Sokol Explains Hot to Avoid an RV Hot-Skin Condition | Hilltopics with Steve http://www.noshockzone.org/rv-electrical-safety-part-iv-%e2%80%93-hot-skin/#comment-529 Mike Sokol Explains Hot to Avoid an RV Hot-Skin Condition | Hilltopics with Steve Wed, 29 Feb 2012 15:31:21 +0000 http://www.noshockzone.org/?p=634#comment-529 [...] avoided if you have an understanding of how the RV electrical system work. Check out Sokol’s fourth installment discussing the hot-skin condition. For more information about your RV’s electrical system, [...] [...] avoided if you have an understanding of how the RV electrical system work. Check out Sokol’s fourth installment discussing the hot-skin condition. For more information about your RV’s electrical system, [...]

]]> Comment on RV Electrical Safety: Part IV – Hot Skin by Brian Cloke http://www.noshockzone.org/rv-electrical-safety-part-iv-%e2%80%93-hot-skin/#comment-528 Brian Cloke Fri, 24 Feb 2012 18:00:05 +0000 http://www.noshockzone.org/?p=634#comment-528 Thank you Mike for that explanation of the Fluke tool. As an aside. Many years ago when I was an apprentice in England a man was killed whilst working on a car by touching 12 volts. So by national code standards anything above 1 to 2 volts is still valid. Maybe fluke could come up with a tool that could read a lower voltage. I guess that a fluke is in my near future. Cheers. Brian. Thank you Mike for that explanation of the Fluke tool. As an aside. Many years ago when I was an apprentice in England a man was killed whilst working on a car by touching 12 volts. So by national code standards anything above 1 to 2 volts is still valid. Maybe fluke could come up with a tool that could read a lower voltage.
I guess that a fluke is in my near future.
Cheers.
Brian.

]]> Comment on RV Electrical Safety: Part IV – Hot Skin by Mike Sokol http://www.noshockzone.org/rv-electrical-safety-part-iv-%e2%80%93-hot-skin/#comment-527 Mike Sokol Fri, 24 Feb 2012 12:57:04 +0000 http://www.noshockzone.org/?p=634#comment-527 Brian, Thanks for your thoughtful comments. In fact, the gold standard way to test for an RV hot skin condition is with the probes of a Digital Voltmeter poked between the chassis of the RV and a solid earth connection. Unfortunately, nobody does that type of test unless there's a known shock problem they're troubleshooting. The idea of using the Fluke VoltAlert came to me when I realized that most high-impedance RV hot skin conditions do indeed go up to around half of the line voltage (60 volts), while most low-impedance hot skin conditions go to full line voltage (120 volts). Also, many hot-skin conditions I've had emailed to me are intermittent and will come and go depending on which way you twist a power plug. Since the lower AC voltage threshold of electrocution is around 40 volts, the fact is that the VoltAlert will show you any potential "LETHAL" hot skin voltage of 40 volts or more. It's not the ultimate test tool since it won't measure chassis to ground impedance, nor will it give you an actual voltage reading. A VoltAlert just beeps at you and lets you know that touching the RV and the earth at the same time could be deadly. But it's a simple, non-invasive test that anyone can do safely since there's no need to touch the RV at all. I've had emails from octogenarians who now test their own RV's and any other RV before they step into them, and a number of them have found hot-skin conditions which they avoided. And I've had an email where this non-contact test was performed after plugging their RV into a relative's garage power outlet while visiting, and the mis-wired outlet energized the RV to 120 volts. I also had an email from someone who did this test on an old RV he was refurbishing, and when it beeped at him he measured the actual chassis voltage as 120 volts. He decided not to take his kids camping that weekend until he found and fixed the problem. He was grateful for the test since he had no idea his dog-bone adapter had a corroded ground pin which broke off inside the plug. And something as simple a a broken dog-bone adapter could have killed him or his child. So I'm sure this simple non-contact test has saved dozens and perhaps hundreds of RVing families from shocks and possible electrocution. And many RV technicians are now using it as a quick check on every RV they plug in. No, it's not the ultimate test, but it will save lives. And it's only $25 or so. Mike Sokol Brian,

Thanks for your thoughtful comments. In fact, the gold standard way to test for an RV hot skin condition is with the probes of a Digital Voltmeter poked between the chassis of the RV and a solid earth connection. Unfortunately, nobody does that type of test unless there’s a known shock problem they’re troubleshooting.

The idea of using the Fluke VoltAlert came to me when I realized that most high-impedance RV hot skin conditions do indeed go up to around half of the line voltage (60 volts), while most low-impedance hot skin conditions go to full line voltage (120 volts). Also, many hot-skin conditions I’ve had emailed to me are intermittent and will come and go depending on which way you twist a power plug. Since the lower AC voltage threshold of electrocution is around 40 volts, the fact is that the VoltAlert will show you any potential “LETHAL” hot skin voltage of 40 volts or more.

It’s not the ultimate test tool since it won’t measure chassis to ground impedance, nor will it give you an actual voltage reading. A VoltAlert just beeps at you and lets you know that touching the RV and the earth at the same time could be deadly. But it’s a simple, non-invasive test that anyone can do safely since there’s no need to touch the RV at all. I’ve had emails from octogenarians who now test their own RV’s and any other RV before they step into them, and a number of them have found hot-skin conditions which they avoided. And I’ve had an email where this non-contact test was performed after plugging their RV into a relative’s garage power outlet while visiting, and the mis-wired outlet energized the RV to 120 volts. I also had an email from someone who did this test on an old RV he was refurbishing, and when it beeped at him he measured the actual chassis voltage as 120 volts. He decided not to take his kids camping that weekend until he found and fixed the problem. He was grateful for the test since he had no idea his dog-bone adapter had a corroded ground pin which broke off inside the plug. And something as simple a a broken dog-bone adapter could have killed him or his child.

So I’m sure this simple non-contact test has saved dozens and perhaps hundreds of RVing families from shocks and possible electrocution. And many RV technicians are now using it as a quick check on every RV they plug in. No, it’s not the ultimate test, but it will save lives. And it’s only $25 or so.

Mike Sokol

]]> Comment on RV Electrical Safety: Part IV – Hot Skin by Brian Cloke http://www.noshockzone.org/rv-electrical-safety-part-iv-%e2%80%93-hot-skin/#comment-511 Brian Cloke Fri, 20 Jan 2012 18:29:52 +0000 http://www.noshockzone.org/?p=634#comment-511 Hello Mike. Thank you for a most interesting series on RV safety. I have been reading Part four Hot Skin. Ready, set,test. Using digital meter test. National electrical code allows 1 to 2 volts as being safe. If however you read 10 or 50 or 120 it is time to pull the power plug. Using non contact tester. The Fluke volt alert works very well as low as 40 volts. If your RV has more than 40 volts on the skin it will alert you to that fact. My understanding of this then is. If the skin of my RV shows less than 40 volts the Volt Alert will not respond or light up. Therefore using National code of 1 to 2 volts as being safe and any voltage above that as being dangerous I would conclude that the Volt Alert would lead me to think the RV is safe when it is not. If this thinking is correct it makes the Volt Alert a deceptive tool to use. Please enlighten me if I am missing something here. Thank you. Brian. Hello Mike.
Thank you for a most interesting series on RV safety. I have been reading Part four Hot Skin.
Ready, set,test.
Using digital meter test. National electrical code allows 1 to 2 volts as being safe. If however you read 10 or 50 or 120 it is time to pull the power plug.
Using non contact tester.
The Fluke volt alert works very well as low as 40 volts. If your RV has more than 40 volts on the skin it will alert you to that fact. My understanding of this then is. If the skin of my RV shows less than 40 volts the Volt Alert will not respond or light up. Therefore using National code of 1 to 2 volts as being safe and any voltage above that as being dangerous I would conclude that the Volt Alert would lead me to think the RV is safe when it is not.
If this thinking is correct it makes the Volt Alert a deceptive tool to use.
Please enlighten me if I am missing something here.
Thank you.
Brian.

]]> Comment on RV Electrical Safety: Surge Strips by Steve http://www.noshockzone.org/rv-electrical-safety-surge-strips/#comment-489 Steve Sun, 25 Sep 2011 03:51:38 +0000 http://www.noshockzone.org/?p=1490#comment-489 Hi Mike, Your 12 part series was very informative. Thanks so much for sharing your expertise with a newbie like me. Hi Mike,

Your 12 part series was very informative. Thanks so much for sharing your expertise with a newbie like me.

]]> Comment on RV Electrical Safety: Part IV – Hot Skin by Mike Sokol http://www.noshockzone.org/rv-electrical-safety-part-iv-%e2%80%93-hot-skin/#comment-482 Mike Sokol Sun, 21 Aug 2011 23:15:18 +0000 http://www.noshockzone.org/?p=634#comment-482 Well, I suspect your 50 amp service is running 2-legs of a 3-phase service, which at full voltage would measure 208 volts from leg-to-leg. That's because of instead of your two hot legs being 180 degrees out of phase like in your home, they're only 120 degrees apart. That's OK since RVs typically don't have anything powered by 240 volts anyways, just a bunch of 120 volt appliances run from one leg or the other. Your RV is really seeing 110 volts on each circuit which is a little low, but certainly within reason. Can you supply the name of the campground and I'll contact them to verify my theory? For your ice maker, I wonder if the GFCI is being tripped by water dripping on circuitry somewhere inside the ice maker itself. That would allow 120 volt current to flow from the hot wire in the ice maker to the fridge chassis ground, and your RV chassis ground is dumping the current to the safety ground, which is exactly what it should do. But anything over 6 milli-amps of ground fault current will trip the GFCI breaker, which is exactly what it's supposed to do. I would carefully inspect the ice maker for any torn gaskets that are allowing water into the electrical motors and such. If this is within warranty, I would simply ask for a new ice maker. In any event, please report your findings.... Mike Sokol Well, I suspect your 50 amp service is running 2-legs of a 3-phase service, which at full voltage would measure 208 volts from leg-to-leg. That’s because of instead of your two hot legs being 180 degrees out of phase like in your home, they’re only 120 degrees apart. That’s OK since RVs typically don’t have anything powered by 240 volts anyways, just a bunch of 120 volt appliances run from one leg or the other. Your RV is really seeing 110 volts on each circuit which is a little low, but certainly within reason. Can you supply the name of the campground and I’ll contact them to verify my theory?

For your ice maker, I wonder if the GFCI is being tripped by water dripping on circuitry somewhere inside the ice maker itself. That would allow 120 volt current to flow from the hot wire in the ice maker to the fridge chassis ground, and your RV chassis ground is dumping the current to the safety ground, which is exactly what it should do. But anything over 6 milli-amps of ground fault current will trip the GFCI breaker, which is exactly what it’s supposed to do. I would carefully inspect the ice maker for any torn gaskets that are allowing water into the electrical motors and such. If this is within warranty, I would simply ask for a new ice maker. In any event, please report your findings….

Mike Sokol

]]> Comment on RV Electrical Safety: Part IV – Hot Skin by Mel Johansen http://www.noshockzone.org/rv-electrical-safety-part-iv-%e2%80%93-hot-skin/#comment-473 Mel Johansen Sat, 13 Aug 2011 15:49:18 +0000 http://www.noshockzone.org/?p=634#comment-473 Recently at a campground the 50 amp service was only putting out 196 volts. The meter read 109-111 volts. I have a surge protector and want to know if this is an ample situation for my motor home. On another note, the ice maker in the refrigerator will work for a week or so and then starts to trip the GFI. After that I have to unplug the ice maker for the rest of the trip. I even used an extension and plugged it into another outlet. Any ideas? Thank you. Recently at a campground the 50 amp service was only putting out 196 volts. The meter read 109-111 volts. I have a surge protector and want to know if this is an ample situation for my motor home.

On another note, the ice maker in the refrigerator will work for a week or so and then starts to trip the GFI. After that I have to unplug the ice maker for the rest of the trip. I even used an extension and plugged it into another outlet. Any ideas?

Thank you.

]]> Comment on RV Electrical Safety: Surge Strips by Mike Sokol http://www.noshockzone.org/rv-electrical-safety-surge-strips/#comment-465 Mike Sokol Fri, 05 Aug 2011 02:17:11 +0000 http://www.noshockzone.org/?p=1490#comment-465 Thanks very much for your comment. I appreciate any feedback you can provide on the topic of electrical safety for consumers. Mike Sokol Thanks very much for your comment. I appreciate any feedback you can provide on the topic of electrical safety for consumers.

Mike Sokol

]]> Comment on RV Electrical Safety: Part III – Outlets by Mike Sokol http://www.noshockzone.org/rv-electrical-safety-part-iii-%e2%80%93-outlets/#comment-464 Mike Sokol Fri, 05 Aug 2011 00:43:56 +0000 http://www.noshockzone.org/?p=446#comment-464 Yes, open neutrals can produce all sorts of strange voltage and current loop effects. And the same sort of condition you witnessed can easily happen in an RV with a 50 amp 120/240 volt plug. If the neutral connection opens up due to a corroded contact or broken wire, then the 120/120 incoming voltage can swing to 60/180 or 20/220 volts, or whatever it feels like depending on the imbalance of the RV loads. I have heard of one RV owner who had a shared satellite coax feed wire to the RV beside it. But his neutral line opened up, so now the shield of the coax cable became the neutral return to the second RV from the first RV with the open neutral connection. They said that the coax cable got hot enough to melt the insulation off the outside, which I don't doubt a bit. That's why it's even more important for owners of large RVs with 120/240 volt 50 amp shore power plugs to make sure their connectors are properly maintained, and the campsite pedestal has the proper voltages and grounds. Really bad (expensive and dangerous) things can happen if you ignore electrical safety rules. Mike Yes, open neutrals can produce all sorts of strange voltage and current loop effects. And the same sort of condition you witnessed can easily happen in an RV with a 50 amp 120/240 volt plug. If the neutral connection opens up due to a corroded contact or broken wire, then the 120/120 incoming voltage can swing to 60/180 or 20/220 volts, or whatever it feels like depending on the imbalance of the RV loads. I have heard of one RV owner who had a shared satellite coax feed wire to the RV beside it. But his neutral line opened up, so now the shield of the coax cable became the neutral return to the second RV from the first RV with the open neutral connection. They said that the coax cable got hot enough to melt the insulation off the outside, which I don’t doubt a bit. That’s why it’s even more important for owners of large RVs with 120/240 volt 50 amp shore power plugs to make sure their connectors are properly maintained, and the campsite pedestal has the proper voltages and grounds. Really bad (expensive and dangerous) things can happen if you ignore electrical safety rules.

Mike

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