SOLVED: current running through trailer
- Thread starter JeremyN
- Start date
danemayer
Well-known member
Re: current running through trailer
Jeremy,
You have a very dangerous condition known as "hot skin". You should shut off power at the pedestal immediately until you can determine what's happened.
This is usually caused by a problem at the power pedestal or with a defective power cord or extension cord, or adapter.
The safe way to work on this problem is by using a non-contact voltage tester. These are available at most hardware stores for about $20. Don't bother getting a $10 unit - you'll want a good one. The non-contact voltage tester allows you to safely check for voltage on the skin and on wires and outlets without making direct contact.
Again, this is most often caused by bad wiring at the pedestal or in the power cords/adapters. Check there first.
You can find out more about this problem at NoShockZone.com
Let us know what you find.
Jeremy,
You have a very dangerous condition known as "hot skin". You should shut off power at the pedestal immediately until you can determine what's happened.
This is usually caused by a problem at the power pedestal or with a defective power cord or extension cord, or adapter.
The safe way to work on this problem is by using a non-contact voltage tester. These are available at most hardware stores for about $20. Don't bother getting a $10 unit - you'll want a good one. The non-contact voltage tester allows you to safely check for voltage on the skin and on wires and outlets without making direct contact.
Again, this is most often caused by bad wiring at the pedestal or in the power cords/adapters. Check there first.
You can find out more about this problem at NoShockZone.com
Let us know what you find.
danemayer
Well-known member
Jeremy,
Glad you got is solved. Please make sure the campground know about the problem. This is not a minor issue. Had the ground been wet, this might not have had a happy outcome.
Also, you may still want to check out your RV with a non-contact voltage tester. It's possible that something is leaking current, but the leaked voltage is flowing to ground without you noticing, which is how the safety system works.
Glad you got is solved. Please make sure the campground know about the problem. This is not a minor issue. Had the ground been wet, this might not have had a happy outcome.
Also, you may still want to check out your RV with a non-contact voltage tester. It's possible that something is leaking current, but the leaked voltage is flowing to ground without you noticing, which is how the safety system works.
Hey, I'm Mike Sokol, the writer of the NoShockZone articles about using a Non Contact Voltage Tester (NCVT) to check your trailer for a hot-skin condition. What everyone else has said here is 100% true. And yes, you really need to document the failed pedestal outlet and bring it to the attention of the campground management. In fact, I think you should name the campground and site number on this forum so we make SURE it's tested and taken care of. However, there is a chance that you have an intermittent break in the ground connection of your own shore power cable. With a NCVT you can wiggle all your power connections while someone holds the NCVT close to your RV, and if you see it blinking on and off, then the break is in your own shore power cord or adapter.
So don't delay this, since a hot-skin is incredibly dangerous. And go ahead and look up my articles on www.noshockzone.org for more info.
evolvingpowercat
Well-known member
Please do investigate some more. On a North Trail even if your trailer's ground connection was open due to a bad shore cable or bad ground connection at the pedestal, this alone would not have made your trailer skin have enough AC voltage on it for people to feel a shock when standing on the ground and touching the door handle. Something else is also wrong. However, with the trailer properly grounded thru the shore cable if no one is getting shocked, and if no breakers are tripping in your North Trail or in the pedestal, finding out exactly what the problem is becomes a bit more involved. There are ways to do it with the shore cable unplugged using a test meter but you may want to leave it to a professional to investigate.
That said PLEASE get one of the non-contact hot skin testers and make sure you don't have hot skin EVERY time you plug in to shore power. If you ever plug in to an un-grounded outlet you are going to have the same exact hazard all over again and as has been said it could be a lot worse than just a shock in the future if the right combination of things happens.
That said PLEASE get one of the non-contact hot skin testers and make sure you don't have hot skin EVERY time you plug in to shore power. If you ever plug in to an un-grounded outlet you are going to have the same exact hazard all over again and as has been said it could be a lot worse than just a shock in the future if the right combination of things happens.
Here's a video of me testing a 40-ft RV for a hot-skin condition. http://www.youtube.com/watch?v=Y8h64X33aKg While I artificially created this condition in the video, it only takes two things to occur for it to happen on your RV. First, you need to have an open safety ground connection. While this can occur inside your RV's circuit breaker panel, it's more likely to be a broken wire in the shore power cord, connectors or adapters. And it can certainly happen in the pedestal outlet itself.
Secondly, you need a source of leakage current. This can be something like water laying in a wiring conduit, screw though a wire in the wall, leaky transformer in a microwave or television set, or even a pinched wire. And this leakage current can vary up and down depending on factors such as temperature, moisture, vibration and component age.
The safety ground wire is supposed to shunt these dangerous currents to "ground" and stop the hot-skin voltage before it even starts. So if your safety ground is correctly wired, then it's IMPOSSIBLE to have a hot-skin condition simply because these leakage current would have tripped a circuit breaker.
However, there is one very dangerous outlet miswiring condition that's often goes unnoticed, something I call a Reverse Polarity Bootleg Ground (RPBG). While difficult to this to happen with new wiring, it's more common than you think in pre 1970's wiring that's been upgraded to grounded outlets incorrectly. And any appliance or RV that's plugged into an RPBG outlet (in say, your garage) will become hot-skin electrified with a full 120-volts at 30 amps or so. The real scary thing is that you CAN"T detect an RPBG outlet using any common testing methods including a 3-light tester or using a voltmeter between H-N, H-G and G-N on the outlet. Here's something I just published in EC&M Magazine on the dangers of RPBG outlets and how it can't be detected by standard testing methods. And here's the final kicker, none of the voltage/surge protectors on the market can detect or disconnect you from an RPBG outlet, yet your $20 Non Contact Voltage Tester can easily find one BEFORE or AFTER you plug into shore power. See http://ecmweb.com/contractor/failures-outlet-testing-exposed for details.
JeremyN
Well-known member
Just an update to my situation. Yesterday, the campground was holding a RV/Trailer Safety and Maintenance seminar at the Camp Host site. The Host called the Service Manager from the local RV dealer and asked him to come about 15 min early to the seminar he was teaching. He did come early and both the Host and the Service Manager came to my trailer. They did confirm the hot skin condition and asked that the campground electrician come ASAP to fix my pedestal. The electrician changed out the damaged fixture while we were in the seminar. The Manager and myself went back over to my trailer afterwards and he confirmed the hot skin condition was gone.
The Manager did say that you need 2 faults to make a hot skin condition, like you guys mentioned above. He recommended that I drop my trailer at my local dealer when I get home on Monday and have them do an electrical check.
Again, I can't thank everyone on here enough for the quick response to my initial post. It helped me resolve the problem in a quick manner in order to save what could have been a very serious injury to someone in my family. I can't thank everyone enough.
The Manager did say that you need 2 faults to make a hot skin condition, like you guys mentioned above. He recommended that I drop my trailer at my local dealer when I get home on Monday and have them do an electrical check.
Again, I can't thank everyone on here enough for the quick response to my initial post. It helped me resolve the problem in a quick manner in order to save what could have been a very serious injury to someone in my family. I can't thank everyone enough.
Yes it should have. There would be a open ground indication and the relays should have remained open and not send power to your RV. I've done a bench test of this using a Progressive Industries Surge/Voltage protector, and it works exactly as advertised.
HOWEVER if you have a portable Surge/Voltage protector plugged directly into the pedestal, and the open ground is in you shore power connection AFTER the protector, then it won't know there's a ground failure going to your trailer. It's still up to you to keep all extension cords and RV internal bonding connections correctly wired.
And yes, a $20 NCVT is the best investment you'll ever make. Plus you can walk around the campground doing hot-skin tests very easily. Since it's non contact, there's no possibility of damaging the finish of the RV with a sharp probe or shocking yourself in the process.
Jeremy, you did exactly the right thing.... didn't accept getting shocked, and didn't leave a broken pedestal for the next person to find. I believe it's socially irresponsible for anyone to simply plug into another outlet that works, leaving behind a potentially deadly situation that could kill somebody not as lucky as you. That's the entire idea behind www.NoShockZone.org - arming yourself with enough knowledge about electricity to recognize when a dangerous condition exists, and then making sure it gets corrected. I'm sure you'll sleep much better knowing you're plugged in safely.
Lou_and_Bette
Well-known member
Mike, I hadn't thought of this...It makes sense that a problem in the cord could arise with all the manipulation it gets hooking/unhooking. What is the procedures for checking the integrity of the cord? I am very comfortable with a VOM
Here's the basics: http://www.noshockzone.org/the-noshockzone-part-xi-—-extension-cord-testing/
However, any standard VOM (or DMM) is going to push so little current through the wires, that it's difficult to read low ohms, plus it can be fooled by loose and corroded connections. That's why I designed my Ground Fault Current Tester (GFCT?) below.
So if you want to go further and be 100% sure that your RV's grounding system can divert full amperage through its ground fault path, then you need to push some current through the RV chassis all the way to the end of your shore power connector. Here's a little $10 gadget I built which is easy and safe for checking your ground continuity since it only uses 12-volts DC from your battery for testing. Since "amps are amps" then a 12-volt test is as good as a 120-volt test for ground continuity, and a lot safer since the voltage is non-lethal.
WARNING: Note that this test is only to be performed on an "unplugged" RV. Never attempt this sort of measurement if you RV is plugged into any sort of shore power. There could be lethal voltages produced if you intermix 12-volts DC and 120-volts AC for this test.
See below for the "pro version" that allows you to read the voltage drop and thus calculate sub-ohm readings. Basically, the voltage across the light bulb should equal the voltage across the battery. Any significant difference (more than a few tenths of a volt) is the result of a poor safety ground connection. The beauty of this test is that it checks for safety ground continuity all the way to your RV's frame, the only thing that really counts. Once you test for the bulb burning brightly on your shore power cord itself, you can then add on extension cords and adapters one at a time to confirm you still have ground continuity. As you wiggle all the connections, the light should stay brightly lit and never flicker or go off. If it does, then you have an intermittent connection in your cable, and a hot-skin condition could exist at any time. This is a really cheap and simple tester that's as close to foolproof as I can imagine.
The only thing to be careful of is that a 12-volt brake light bulb gets very hot since it draws around 2 amps and 24 watts, so it could burn your carpeting if a bare bulb is left laying on the floor of your RV while it's on. So I'm going to build one using a little plastic brake light fixture.
Here's the "consumer version" that only needs to be plugged into a 12-volt DC outlet for powering.
Please let me know if any of you guys build one of these and take a picture. I think that ALL RV's taken into a service shop with potential hot-skin conditions should have this test performed. But I don't know of any commercial products like this.
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