# Possible Short? Trailer Frame Is Hot



## Rittenhouse (Dec 13, 2014)

Hello, gentlemen:

My 2004 28RSS hooked up to 30 amp power, water, and sewer at an RV park in Phoenix.

Just tonight one of my kids touched the metal steps from a damp spot on a concrete pad. He felt a shock. I tested it and got the same result.

Wow. Where do I begin to locate the cause of this?


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## Leedek (Nov 28, 2010)

My bet is that your trailer is fine but the pedestal power has a problem. I would probably disconnect from the pedestal and inform the park of a suspect power problem. In the future you should carry an AC Polarity Tester. Looks like the photo. I carry one to plug into my outlet on the trailer after connecting to the pedestal. Admittedly my procedure is a little backward. I am open to another. I also plug into the receptacle at the pedestal prior to energizing the trailer. REMEMBER: TURN OFF THE CIRCUIT BREAKER AT THE PEDESTAL. .. PLUG IN THE TRAILER... TURN THE BREAKER BACK ON.... CHECK POLARITY INSIDE THE TRAILER.










I know Robert from Texas will be helpful. The biggest concern is to avoid being electrocuted. Good luck.


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## Tiger02 (Apr 16, 2006)

As Leedek stated it is most likely an issue at the pedestal and the ground connection. Most RVs do not have grounding cables or rods with them, so they rely on the hook up to provide that ground. If that is not present then that can create a floating ground where the ground of the RV is different from the true ground (puddle on concrete pad would be true ground). Polarity and voltage may be spot on, but if the pedestal is not grounded correctly or your ground wire is faulty you can have a dangerous situation. Good luck with this issue.

Vince


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## Leedek (Nov 28, 2010)

Just one other bit of advice on RV park pedestals. The AC polarity checker can be connected to the adapter shown below. All you do is plug the two together and then plug that into the pedestal. You can check proper polarity at the pedestal without having your trailer in the mix. The two other posters here.... well lets just say... I really like Outbackers.com

RV Electrical Adapter Plug 30AMP Male to 15AMP Female Motorhome Camper Triangle










Now lets get the tackle box and go fishing!


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## CamperAndy (Aug 26, 2004)

If you do not have a polarity checker you can do the same thing with a meter. Check from the small blade to the ground pin. If you do not have voltage the polarity is reversed.The small blade is the hot leg.


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## Rittenhouse (Dec 13, 2014)

Wow, thanks, guys. This is a lot to chew on.

I started by asking one of the park's maintenance guys to show me to the breaker -- there was none on the power post itself. He located one at a nearby box and turned it off while I unplugged my cord, then plugged it back in. Then he switched the breaker back on. (I confirmed it was the correct breaker by watching a light on my trailer.)

Then I took voltage readings between my metal step and some wet concrete: 28 VAC between the step and the earth. (On the DC meter I got .36 volts but I don't know if that means anything.)

At my trailer's outside 120 VAC outlet, I got 119 VAC between the hot and neutral sides; 53.5 VAC between the hot and the third (ground) hole, and 31.1 VAC between the neutral and third.

From the hot side to the earth I got 115 VAC.

So, in sum, my chassis is still hot relative to the earth at 28 VAC. I will try some of these other suggestions you've kindly offered. Thank you.


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## CamperAndy (Aug 26, 2004)

You should have no potential difference between the Neutral and ground. Any voltage reading between Neutral and Ground prong or any difference in Hot to Ground/Neutral indicates a high resistance connection, it should be less than 1 ohm between Neutral and Ground.

I would disconnect from the pole and repeat the measurements from the pole outlet.


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## Rittenhouse (Dec 13, 2014)

The park electrician came by and tested the outlet. He found some looseness in the wires at the breaker, but when he checked the outlet I use, he found it well-grounded.

We still get stray voltage at the chassis. He tested the doorside outdoor outlet and found the GFCI protecting it was faulty. He suggested I check the GFCI upstream of that outlet for a defect or failure. I guess I can just replace it and see if that fixes the stray voltage problem.


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## Rittenhouse (Dec 13, 2014)

Instead of taking the electrician's diagnosis, I started throwing breakers while testing the chassis voltage leak.

With all breakers on, I got 22VAC.

Throwing the GFI breaker had no effect.

The only breaker that changed that number was one stamped "12V GEN." Throwing it reduced the number to 9 VAC.

What does 12V GEN refer to?


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## Leedek (Nov 28, 2010)

Rittenhouse said:


> What does 12V GEN refer to?


From an Outbacker post of 2005 " the 12volt power/charger part of the converter. I do this by switching off the circuit breaker labeled 12V/Gen." The converter in your trailer supplies 12VDC to charge batteries when hooked to shore power (pedestal). 

In any case, I still believe that the pedestal and RV park equipment is the problem. Good luck.


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## Rittenhouse (Dec 13, 2014)

New development: I opened the battery box to find the top of the battery cracked open and caps askew. Still reads 13+ volts with everything hooked up.

Think this is a clue to the stray voltage?

Also: What's the best way to isolate the battery from the system until I can get a new one? Frankly, I never use it anyway.


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## CamperAndy (Aug 26, 2004)

To isolate the battery,

Power off the converter at the breaker panel.

Disconnect the battery ground cable. It should be the White wire and typically it is grounded to the curb side of the tongue. You can disconnect it directly from the battery. Once you have the ground cable off then take the positive cable off.

Use baking soda to neutralize the acid on the battery supports and then rinse with plenty of water. Once dry paint with a quality rust converting primer.

Sorry I went a little past isolating the battery.

BTW at Robert said the battery is not the source of the short but likely just a symptom


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## Rittenhouse (Dec 13, 2014)

Thank you, CamperAndy. I'm looking for work right now, so calling in a pro is financially out of my reach. I appreciate your guidance. I have rewired a whole house and car by myself. This hybrid system has me feeling my way along.

I picked up a new 24 series deep cycle battery at Costco and started to hook it up, but immediately got a big spark and the air conditioner kicked off.

Without being connected, the battery terminal wires read 13.6 VDC.

I'm reluctant to try hooking up the new battery again until I figure out where the problem(s) is/are.

EDIT: Well, here's a twist. When I flip off the breaker labeled 12V GEN, the air conditioner stops. Is that supposed to happen?

EDIT2: Of all the knuckleheaded things ... just realized the battery was hooked up backwards for three months. I let some knucklehead charge it for me (claimed his charger would rehabilitate it), and he put it back in reverse polarity. So that problem is solved.

Still getting stray voltage at the chassis, though -- 28 VAC with the GFCI breaker on, about 14 with it off.


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## CamperAndy (Aug 26, 2004)

Rittenhouse said:


> I have rewired a whole house and car by myself. This hybrid system has me feeling my way along.
> 
> EDIT2: Of all the knuckleheaded things ... just realized the battery was hooked up backwards for three months. I let some knucklehead charge it for me (claimed his charger would rehabilitate it), and he put it back in reverse polarity. So that problem is solved.
> 
> Still getting stray voltage at the chassis, though -- 28 VAC with the GFCI breaker on, about 14 with it off.


The above is why I indicated the wire color and location of the ground so you could confirm it, now to help you understand why. Since the trailer has both 120v house wiring and 12v automotive wiring and the more dangerous of the two is the 120v, where Black is HOT and White is NEUTRAL. With that in mind they wired the 12v wiring so that the white wire was the safe wire. The hot wires in the 12v portion of the system will be white with a colored trace or it will be black.

Now for some additional free trouble shooting. Behind the converter is the ground/neutral buss. Get access to it and make sure all the wires inserted into it are tight. From this buss you should have a heavy bare wire that is run to the frame, this connection is typically on the driver side of the trailer and will also have the main shore power ground connected to the same ground lug. Make sure it is tight and has a good connection to the frame. This connection could have corrosion that can result in a higher than acceptable impedance.

Let us know what you find.


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## bbwb (Apr 4, 2008)

My bet is that you have one outlet with the polarity reversed or a reversed wire off of a breaker. Either use a tester as shown above or disconnect your shore power and open up each and every outlet and make sure the black wire is on the brass screw and the neutral is on the silver screw.
Also, here is a link to an informative write up on RV grounding systems.
http://www.beamalarm.com/Documents/120_vac_in_your_rv.html
bbwb


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## Rittenhouse (Dec 13, 2014)

Thank you all for your suggestions. I still don't have a solution; here's what's been done so far:


Changed power poles at camp; even moved to a different camp. No difference.
Checked the connections to both the silver bars behind the converter -- all tight.
Replaced the GFCI in the bathroom. (It was wired correctly.)
Checked wiring at 120V plugs, including the microwave -- all correct. I did not check the refrigerator plug.

I have not followed the bus wire to the frame yet, as suggested by CamperAndy.

Also have not checked polarity on each breaker.

One odd thing I noticed when flipping breakers is, the stray voltage at the frame drops from 27.6VAC to .3VAC when the top breaker is OFF. Then as I flip ON the remaining breakers one at a time, I get different stray voltage readings. I took a photo and tagged it to illustrate:


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## Rip (Jul 13, 2006)

Check the connection at the 4x4 box where the cord comes into the trailer and goes to romex then to the panel, someone on here had bad joints in the 4x4 box and the wires were melted !


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## Rip (Jul 13, 2006)

http://www.outbackers.com/forums/index.php?showtopic=48209&hl=melted%20wires&st=15 look at this


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## Leedek (Nov 28, 2010)

When all has been checked - input cable, j-box as stated above, and all other connections then it may be time to consider replacing the converter.









WFCO 8955 Replacement You may have fried it when the incident happened. It is important to check all the peripherals connected to the converter prior to changing it out. It would really suck to fry the new one because of an overlooked short to ground somewhere. It seems this problem has been plaguing you for quite sometime. Maybe the RV doctor needs to be called. Good luck.


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## Rittenhouse (Dec 13, 2014)

With regard to getting at the power cord connection where it enters the back of the trailer (28RSS), does one reach it through the interior, as pictured? (If so, how does that carpeted box come off?)


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## Leedek (Nov 28, 2010)




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## Rittenhouse (Dec 13, 2014)

In case anyone's still watching this thread...

I exposed the junction box where the coiled extension cord enters the back of the camper.

I found the wires looking OK except the blue one, which ends (as you see here) in midair. Actually, found it resting against the metal junction box.

With it touching the box, the trailer chassis registers 0 volts AC.

With it NOT touching the box, I get 2.7 volts AC from chassis to ground.

Which is strange, because a few days ago, my son reported getting a shock hooking up the water hose and standing on wet ground. This was before I exposed the junction box, so the blue wire was almost certainly resting against the box.

I'm thinking of just adding a (temporary) ground wire between the chassis and the dirt to protect against shock.


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## H2oSprayer (Aug 5, 2006)

If I'm looking at that photo correctly, the green wire that isn't hooked to anything is your main ground wire. That wire should be connected to the two bare copper wires and looks to have come loose from the wire nut. Without this, your camper is not grounded when plugged into shore power. Be sure to first unplug the camper from shore power, then verify that the black and white wires are both securely joined with the wire nut. Had it of been one of those wires making contact with the metal box, we would certainly be reading a different story in this thread.


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## Rittenhouse (Dec 13, 2014)

Thanks, H2o Sprayer. I have reconnected the wires. Not sure they were ever connected, because I had to manipulate the bare wires to get them close enough to the green one for splicing. My guess is, Keystone's electrician messed up.


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