Shocked by Frame to Ground

[Brother Les]

Originally Posted by Herk7769

Start with the article in Big Baron's post and then go to the ground/Neutral lugs from the converter.

One or the other should fix it.

I flew through the thread and typed out a plea before I read the article. I will go with the suggestions.
thank-you.

[B and B]

Having worked with tower grounding and AM transmitters the bonding of connections are important in both RF (Radio Frequency) and AC power. Often a compound called Penetrox is used.
PENA134 - Burndy - Electrical Joint Compounds | Galco Industrial Electronics

This will eliminate corrosion between dissimilar metals and provide a electrical connection between cleaned surfaces. This is available at Lowes or Home Depot. We used a lot of alumium connectors for high power 600 vac 500 amp services for UHF transmitters and always used penetrox to eliminate heating and damage.

One bigger question is code surrounding Neutral bonded to Ground. According to Ontario and Canadian Electrical code a sub panel can not have the neutral and ground bonded. The park service panel distribution is where they are bonded. The National electrical code in the US may be different and the trailer have CSA for Canadian Certification. There is the code that says no and the reality the Trailer is safe and meets code as per the CSA certification.

The outlets in the trailer are protected by GFCI so the bonding from a safety aspect might be a non issue but hot skin or what Lou had could still happen as the return ground path is on the neutral instead of the ground. With high power usage in a park, all being single phase, it is quite possible a lot of neutral current exists creating a AC potential between the bonded trailer ground and real earth ground. When I spec an install I always have double sized neutrals added to compensate for single phase loads.

Sorry for going all engineer on you with this

Brian

[camaraderie]

I just got one of these NON CONTACT VOLTAGE SENSORS (amazon) for 15 bucks to check the steps for hot skin after plugging in anywhere...but also useful for finding hot wires throughout the house and coach. I got this one because the adjustability makes it good for both 12 and 120V sensing and you can make it less sensitive to isolate THE wire with current in a bundle.
The ONLY thing I don't like about it is that you have to hold the on switch rather than there being a click on switch. Otherwise, highly recommended.
http://www.amazon.com/Sperry-Instruments-VD6505-Adjustable-Sensor/dp/B000GLAC5G/ref=sr_1_1?s=hi&ie=UTF8&qid=1408116681&sr=1-1
We also have a circuit tester like Herks above and give that a big DITTO too!

[RPAspey]

Originally Posted by B and B

Having worked with tower grounding and AM transmitters the bonding of connections are important in both RF (Radio Frequency) and AC power. Often a compound called Penetrox is used.
PENA134 - Burndy - Electrical Joint Compounds | Galco Industrial Electronics

This will eliminate corrosion between dissimilar metals and provide a electrical connection between cleaned surfaces. This is available at Lowes or Home Depot. We used a lot of alumium connectors for high power 600 vac 500 amp services for UHF transmitters and always used penetrox to eliminate heating and damage.

One bigger question is code surrounding Neutral bonded to Ground. According to Ontario and Canadian Electrical code a sub panel can not have the neutral and ground bonded. The park service panel distribution is where they are bonded. The National electrical code in the US may be different and the trailer have CSA for Canadian Certification. There is the code that says no and the reality the Trailer is safe and meets code as per the CSA certification.

The outlets in the trailer are protected by GFCI so the bonding from a safety aspect might be a non issue but hot skin or what Lou had could still happen as the return ground path is on the neutral instead of the ground. With high power usage in a park, all being single phase, it is quite possible a lot of neutral current exists creating a AC potential between the bonded trailer ground and real earth ground. When I spec an install I always have double sized neutrals added to compensate for single phase loads.

Sorry for going all engineer on you with this

Brian

I think this is the same in the US. Neutral and ground are not to be bonded except at the service. I could be mistaken, as its been a while since studying the NEC. I know that in my TT they are separate.

[bubbles]

Originally Posted by RPAspey

I think this is the same in the US. Neutral and ground are not to be bonded except at the service. I could be mistaken, as its been a while since studying the NEC. I know that in my TT they are separate.

The words electrical bonding refers to the process of joining two metals together providing the least electrical resistance between the metals (this includes crimp on wire terminal lugs used to ground wires to wherever). Electrical ground (neutral returns included) circuits differing in function/type and amount of voltage/signal etc. should not be combined to a common ground point (stud) rather to its own dedicated ground point. Likewise identical function wiring may be combined on a common stud (point). Everyone probably knows this though so I'm done.

[Oaklevel]

Originally Posted by camaraderie

I just got one of these NON CONTACT VOLTAGE SENSORS (amazon) for 15 bucks to check the steps for hot skin after plugging in anywhere...but also useful for finding hot wires throughout the house and coach. I got this one because the adjustability makes it good for both 12 and 120V sensing and you can make it less sensitive to isolate THE wire with current in a bundle.
The ONLY thing I don't like about it is that you have to hold the on switch rather than there being a click on switch. Otherwise, highly recommended.
http://www.amazon.com/Sperry-Instruments-VD6505-Adjustable-Sensor/dp/B000GLAC5G/ref=sr_1_1?s=hi&ie=UTF8&qid=1408116681&sr=1-1
We also have a circuit tester like Herks above and give that a big DITTO too!

Never tried this brand but know their limitations & always test them on a known source before using as the battery inside will eventually die. The ones I have used only check AC though not 12V.

[WY Husker Fan]

Originally Posted by Herk7769

It was directly under the converter at the frame.

The green wire went directly from the converter's ground buss to the frame (via a hole in the floor) and the Neutral from the converter's buss went to another Neutral buss screwed to the floor; and then to the frame via the same hole as the green ground wire.

Herk,
Are you sure the buss screwed to the floor is not the common buss for the DC side? The neutral and the equipment ground should NOT be bonded together in the trailer. The only place the neutral and ground should be bonded is at the main service disconnect in the home or campground electrical system. If they are tied together in the trailer, that creates a parallel path for neutral current through the ground conductor which is not good.

Brad

[Herk7769]

Originally Posted by WY Husker Fan

Herk,
Are you sure the buss screwed to the floor is not the common buss for the DC side? The neutral and the equipment ground should NOT be bonded together in the trailer. The only place the neutral and ground should be bonded is at the main service disconnect in the home or campground electrical system. If they are tied together in the trailer, that creates a parallel path for neutral current through the ground conductor which is not good.

Brad

Gonna look again today, but that is what I recall finding.
Lou

[campnqueen]

WOW I would have never thought about the battery. GREAT POINT Herk.

[Herk7769]

So, just when I thought I had it all figured out ... Monkey Wrench.

The buss screwed to the floor is indeed the 12 volt DC "Ground Buss."

Unbonded the AC Ground and AC Neutral in the camper and my 30 volts AC is back; frame ground to Neutral.

Further troubleshooting is I have about 2 volts AC between the AC ground and AC Neutral with all breakers on except the L/R GFCI circuit/Converter (hots are soldered together and inserted at the breaker).

In process of trying to isolate which leg is the culprit. I am afraid the issue is in the converter. (Film at Eleven)

[RPAspey]

Go solar and never turn the converter back on!!! I haven't for years.

[WY Husker Fan]

Lou,

I suspect a bad connection somewhere between your camper neutral buss and the supply circuit neutral. This would introduce a low resistance into the circuit which would create the voltage potential when there is a load on the neutral. Since you had the problem a two different locations, probably in the camper. A loose connection in the ground conductor would not cause the voltage potential because there should not be current on the ground conductor. I'm not sure how your autotransformer is connected so I can't really say whether that has anything to do with it or not. With the neutral and ground bonded, you were forcing the two to be at the same potential and thus the ground was probably carrying some of the neutral current. When you removed the bond, with the neutral and ground bonded in the supply circuit source panel, the current in the neutral with the series resistance of the bad connection would result in the 30 volts between the ground and neutral in the camper.

Brad

[WY Husker Fan]

Lou,

I read your last post again and what you described about the 2 volts without the converter on fits my previous explanation. The converter is probably there highest load so turning it on increases the neutral current and this increases the voltage between the neutral and ground. Try turning on something else with a high current load (water heater or air conditioner) and I bet the voltage between the neutral and ground goes up.

Brad

[B and B]

Originally Posted by Herk7769

So, just when I thought I had it all figured out ... Monkey Wrench.

The buss screwed to the floor is indeed the 12 volt DC "Ground Buss."

Unbonded the AC Ground and AC Neutral in the camper and my 30 volts AC is back; frame ground to Neutral.

Further troubleshooting is I have about 2 volts AC between the AC ground and AC Neutral with all breakers on except the L/R GFCI circuit/Converter (hots are soldered together and inserted at the breaker).

In process of trying to isolate which leg is the culprit. I am afraid the issue is in the converter. (Film at Eleven)

Hmmm too hots on one breaker according to Canadian code is illegal but then RVIA has its own approved code.

[Herk7769]

Originally Posted by WY Husker Fan

Lou,

I read your last post again and what you described about the 2 volts without the converter on fits my previous explanation. The converter is probably there highest load so turning it on increases the neutral current and this increases the voltage between the neutral and ground. Try turning on something else with a high current load (water heater or air conditioner) and I bet the voltage between the neutral and ground goes up.

Brad

OK, now I know where to start looking and I don't have to worry so much about buying a new converter.

Thanks. Will update this thread when we get back from Oregon in 2 weeks. Camper is offline and battery disconnected.

[Herk7769]

After weeks of searching I found the culprit.

When I installed the Franks unit, I used a male pigtail on the "power center side" and a female pigtail on the "wall socket side" so I could bypass the Franks if there was ever a problem by plugging the two pigtails together.

During the troubleshooting I did that and still had my hot frame, so I moved on to the actual coach wiring.

Well after weeks of work, I decided to start over after talking to Mike Sokol and my Electrician friend who retired from Hershey as an electrician.

I found that inside the bare ground/green wire "wire nut" on the power center side pigtail junction box, the bare 30 amp Romex ground wire had vibrated out of the wire nut. Since I had taped all the nuts in place in that junction box (as my technique), it was not obvious by observation that the wire was not making contact.

All is well now.

[TURBS]

Originally Posted by Herk7769

After weeks of searching I found the culprit.

When I installed the Franks unit, I used a male pigtail on the "power center side" and a female pigtail on the "wall socket side" so I could bypass the Franks if there was ever a problem by plugging the two pigtails together.

During the troubleshooting I did that and still had my hot frame, so I moved on to the actual coach wiring.

Well after weeks of work, I decided to start over after talking to Mike Sokol and my Electrician friend who retired from Hershey as an electrician.

I found that inside the bare ground/green wire "wire nut" on the power center side pigtail junction box, the bare 30 amp Romex ground wire had vibrated out of the wire nut. Since I had taped all the nuts in place in that junction box (as my technique), it was not obvious by observation that the wire was not making contact.

All is well now.

This is why I was told to never "black tape" a wire nut.

Can't see if a wire has "slipped out"

Albeit I think it's still a good practice.

Good you found it lou!

TURBS

"SABRE OWNERS UNITED"

[Herk7769]

It would have been obvious if the wire was insulated because I would have seen bare wire showing it was not inserted far enough. As it was bare copper, I had no idea it had not engaged the wire nut spring.

Gonna do some soldering this time.

[cabranch47]

I have wired/rewired a number of houses. I make it a point to twist the wires together before installing the wirenuts. Saves having to deal with problems such as yours. Just my thoughts.

[OldCoot]

Originally Posted by cabranch47

I have wired/rewired a number of houses. I make it a point to twist the wires together before installing the wirenuts. Saves having to deal with problems such as yours. Just my thoughts.

That's how I was told years ago by an old electrician and that's how I do it and tape the wire nuts also. He also taught me to wrap the nuts and continue about an inch above the nut, fold the tape back over the nut and wrap it down from the top to the wires themselves in a continuous wrap. It sure guarantees the nut will not come off.