Unprotected Wiring

dgflaw

Member
I had to replace my hot water heater electrical element, so I switched off the breaker for the Hot Water Heater. Safety first. Stuck my screwdriver on the screw for one of the wires connected to the element. POW!! ZAAAP! :mad::mad:

HUH?? Luckily it tripped the shore power breaker for the plug we were plugged into. Replaced the element and started to trace wiring. The AC wiring is backwards. Neutral is 120V above ground, the live (black) wire is at ground, neutral and ground are NOT connected together as required by the National Electrical Code.

What does this mean? None of the circuits are protected by the breakers since they are in the neutral leg. If you short out the white wire on any circuit (which should be the neutral leg) you will suck as much current as the shore power can provide, not limited by the breaker. You could suck 50 A through a 15 A set of wires, or until the wires overheated and melted.

Now I have to figure out where the cross over has occurred. I can't join the neutral and ground since that would be a dead short across the input power. The is some mixup between the shore power plug and the circuit breaker panel. Any thoughts on how to proceed?? I have wired the last four homes that my wife and I built, so I know what I am doing, but this is our first RV and I don't want to toast it.

Jim Graziano
(Mt Hermit)
Hotchkiss, CO



 

cookie

Administrator
Staff member
Hi Jim and welcome to the forum. Sounds like you have a small problem on your hands. I think you may get some help on this forum.
One thing I always do when disconnecting power is to check everything with my meter just in case. You now have shown justification for doing just that.
I hope that you bought this rig used and some previous owner thought he knew about electrical circuits. I doubt it came new from the factory that way.
I would start at the pedestal and make sure that is wired correctly. Use a meter.
If that checks out move on to the shore cord. Check continuity from one end to the other based on ground, neutral, 120V and 120V.
Then check the connections on the back of the Marinco plug on your rig. Again making sure that the wires are where they should be.
That wire will run to your breaker panel. Be sure that the red and black are running to the breakers, the white to the neutral buss and the bare copper to the ground buss.
If you go through these steps you will find the problem.
Any other questions just ask. We are here to help.

On edit, have you looked at the breakers? Black wires to the breaker and white to neutral buss?
Are you getting shocks??

Peace
Dave
 

rebootsemi

Well-known member
Cookie pretty much covered checking out the 120 volt circuits. In your post you state that the neutral and ground are not connected together as per NEC. The neutral and ground must only be together in the MAIN supply panel no where else in the circuit, not in any sub-panel which is what a power pedestal is. This site will give you all you need to know about RV power wiring and supply. Sounds to me like somebody has wired a plug wrong happens more than one would think.

http://www.myrv.us/electric/
 

dgflaw

Member
Thanks Guys!! I tracked the problem to our meter pedestal. When the electrician set the meter, he added an outlet for the carpenters, but the leads are reversed.

We have done mostly boondocking, running off our generator and when home plugging in to an outlet in our hay barn. This time, we are turning around quickly, so we pulled up to the meter. OOPS! Your information is enlightening - never thought to check a campground pedestal. Now we sure will - and will rewire our meter outlet. Since it is not required to tie the neutral to the ground on the RV circuit breaker panel, as is done in a residence, would it be a good idea? It would trip the breaker and prevent an unprotected neutral, as I encountered, if the line and neutral were switched at the pedestal.

Jim Graziano
Mt Hermit
Hotchkiss, CO
 

cookie

Administrator
Staff member
Jim, now would be a good time for you to invest in some sort of electrical protection device.
I have the Progressive EMS with remote. If there is a problem at the pedistal it will tell me. Hopefully protect all my electronics. It has done its job three times for me.

Peace
Dave
 

TravelTiger

Founding Texas-West Chapter Leaders-Retired
Jim, now would be a good time for you to invest in some sort of electrical protection device.
I have the Progressive EMS with remote. If there is a problem at the pedistal it will tell me. Hopefully protect all my electronics. It has done its job three times for me.

Peace
Dave

Ditto here. Had a certified electrician mis-wire a 30 amp plug he installed. Fried many things in the NorthTrail. :( Now, we never plug in ANYWHERE without the EMS. Low voltage tripped it 3 times this weekend!

E
 

wdk450

Well-known member
Gang:
I thought I would share this work story on the subject. I maintained the radiant warmers and attached phototherapy lights used on preemie babies at our medical center. We had a whole bunch of one brand and model. One day I got a call from the nurses that on one warmer although they had turned off the units' main power switch, the attached phototherapy light STAYED ON!!! A lot of electrical probing and head scratching finally found a connector cable to a circuit board before the main power switch that had a half twist in it so that the supplied HOT electricity connected to the equipment wiring NEUTRAL!!! Well, all that was needed was a pinched hot (now miswired neutral current ) wire to the grounded metal chassis of the phototherapy light (that would have normally blown the fuse and shut of the power) to complete the circuit for the light and the light to stay on as long as the unit was plugged into the wall. To restate this, the current flow was from the wall hot, into the equipment neutral. through the lamp load, out the equipment hot wire, which was shorted to ground to complete the circuit (grouind being tied to neutral at the hospital electrical feed). I found ALL of them wired this way!
I had a big fight with the manufacturer who said that this miswiring was of no importance, and no medical recall was needed. I got it written up in the medical device equivilent of Consumer Reports magazine, "Health Devices", though. All I had to do to fix it was use a Molex extractor tool to reverse the pins on the connector.
 

Photon

Member
Since it is not required to tie the neutral to the ground on the RV circuit breaker panel, as is done in a residence, would it be a good idea? Jim Graziano
Mt Hermit
Hotchkiss, CO

More like it is NOT ALLOWED to tie neutral to ground than NOT REQUIRED on the RV. Only tied together at one place, and that is at the pedistal. If you want to take some protective action, meter the outlet on the ped before you connect the RV.
 

stefan_s

Member
Ditto here. Had a certified electrician mis-wire a 30 amp plug he installed. Fried many things in the NorthTrail. :( Now, we never plug in ANYWHERE without the EMS. Low voltage tripped it 3 times this weekend!

E

You would think that someone who is certified and gets paid the big bucks would not make a simple mistake like that. I am glad that Jim only got startled a bit when hitting the live wire. I know it would have sent me flying backwards and mouthing off several choice words. Rule of thumb is always use a meter to check for a live wire. That was one of the first tips I ever got from an Indianapolis electrician while working on my first home project years ago. I always do this now even when messing with the outlets and such in my house. Thanks for the link Rebootsemi - I have that bookmarked now on my laptop!
 
Last edited:

TravelTiger

Founding Texas-West Chapter Leaders-Retired
stefan, yeah, worst part was, it was someone we know. It was their first wiring for an RV. He offered to pay for all the damage. He said it was a teachable moment, for sure, as he had a small RV park to wire in the coming weeks. WHOA, now that would not have been good to screw up.

E
 
Top