No grounded outlets, shoreline flare up!

[SaSuVa]

At the same exact time the pedestal at the campground flashed a long spark that the neighbor came over and told me about, while I was in the camper, all the outlets lost the ground. Well, all except the GFI. The Main and Receptacle breakers tripped in the converter.

What would cause this, all the outlets work fine, save this issue.

The pedestal is grounded, I checked.

The ac panel inside is grounded, so the shoreline 50 amp is grounded, the plug is grounded as well.

Is it the transfer switch, how do I check that?

The MH has a neutral isolation, not connected to the ground.
Thank you,
Sam

[DriVer]

Originally Posted by SaSuVa

Is it the transfer switch, how do I check that?

Sam, As a quick check - Disconnect the shore power, start the generator. See if the generator will throw the power to the coach.

I blew up a transfer switch when we were struck by lightning.

[SaSuVa]

Great idea,


I did not mention, I do have power from the generator, but no ground to the outlets when the genny is running either.

I had a similar incident, lost a transfer switch, I am wondering if there is a connection in there, I am going to do some more checking tomorrow.

First rate idea, thank you,

Sam

[wa8yxm]

I suspect the problem is park-side.. But can't be sure.

[TQ60]

First try to get a wiring diagram from the manufacturer.

Now get a volt-ohm meter and verify that it works and you know how to use it.

One of the plug testers that indicate wiring issues they are cheap and easy.

The generator does NOT provide any ground, nothing does, it is Safety Ground, any live wire touches this the breaker gets blown.

You may have a blown out transfer switch or bad connection, carefull testing will indicate the issue, take your time and do not get hurt.

Locate your ac-load center, Turn off ALL power sources, (shore line, inverter and generator) remove the front cover and inspect all of the wiring, verify nothing is burnt up.

I assume you have measured the ground against a reference and are not getting an indication.

With your coach NOT plugged in to shore line and the generator NOT running there should be no connection between "Safety ground" (green wires or round pin in plug) and the return (white wires or fat prong in outlet).

This is normal.

Now measure safety ground to chassis ground, if not connected the likely connection is a wire from the ground buss inside the load center to the chassis ground.

Depending on the size of this wire, or the connection to ground, a surge somewhere could have blown it.

This wire needs to be capable of blowing any supplying breaker, so if you have a 50 amp system the wire size should be #6 minimum from the ac load center ground buss to the chassis ground.

Once this is repaired now measure from the chassis ground to the ground coller on your shore line, again, look for blown or loose connections if connection is not found.

Once all of this is tested, plug in the shore line and test the plugs, you should be able to measure 120 VAC at your outlets hot (small hole) to both the return (fat hole) or Safety ground (round hole).

If this works then try the generator.

[RJay]

Originally Posted by SaSuVa

At the same exact time the pedestal at the campground flashed a long spark that the neighbor came over and told me about, while I was in the camper, all the outlets lost the ground. Well, all except the GFI. The Main and Receptacle breakers tripped in the converter.

What would cause this, all the outlets work fine, save this issue.

The pedestal is grounded, I checked.

The ac panel inside is grounded, so the shoreline 50 amp is grounded, the plug is grounded as well.

Is it the transfer switch, how do I check that?

The MH has a neutral isolation, not connected to the ground.
Thank you,
Sam

Could you be specific and tell us what symtoms you are having that makes you think you lost a ground? Are you sure it's a ground and not a neutral? A ground, as another poster mentioned, is a safety feature that protects against shock hazards, so I'm wondering how you know it's a ground.

[SaSuVa]

Thank you gents, I will post the results,

Sam

[SaSuVa]

At exactly the same time the CG shoreline sparked, there was a surge that took out my protector and open/short circuit identifier. When I tested the outlets, there was not ground at any of the outlets, except the GFI, and that was the only one. The CG pedestal had proper grounding.

As has been stated, safety first, unhook ac\dc, batteries, etc. I tested safety ground, and I did not have it. Tracing the wires to chassis ground, I found the connection corroded. The connection bolt came out, (I love the south), and after wire brushing the connectors, bolt, star washer and frame, reconnected it with a little lubricant.

With the CG shoreline restored, the tester indicates good grounds through the RV.

Thanks to one and all for the support and great ideas.

Sam

[RJay]

There is something still not right here. In a motorhome AC electrical system, the ground is isolated and continuous throughout the motorhome to the generator transfer box. The ground is connected to the utility distribution system at the power pedestal when the AC cord is plug into the pedestal receptacle. Inside the motorhome, the AC ground is connected to the chassis at one and only one point and that serves as a bond. The bond prevents shock hazard. If a live AC conductor was to come in contact with the chassis, fault current would pass thru the chassis to the bonding point and then along the AC ground completing the circuit and tripping the appropriate breaker. So cleaning the bonding point couldn't have solved your problem. One possibility is that since the arc took place at the power pedestal there could have been a burn spot or arc deposits on the ground pin due to the arc, when you plugged the power cord back in after you repaired the chassis ground the friction could have scrapped off the residue completing the ground connection. You might want to check the pins on your power cord.

[SaSuVa]

Good call,

There is burn residue on the end of the ground blade of the shoreline.

Makes me wonder what the CG electrician didn't see.

Sam

[RJay]

Sam,
If you haven't already, you might want to wire brush the pins on the power cable and file down any burs that are present.

[TQ60]

Since the OP did indeed find a poor connection and after the repair the problem was solved we can assume that was it.

My stickler is this...

Was the repair a repeatable repair?

To better explain review this scenario
You come home from work and wife states light in bathromm does not work.
You change the bulb, flip the switch and there is light.
Did you fix it?
What was wrong with it?
Bulb?
How do you know for sure?
You install the original bulb and wow, it works too!
So maybe it was not the bulb!

Back to point.
If the grounds were being measured between chassis and the round pin, then the bad connection at what would be same as "meter ground" (place in the ac load center where neutral/safety grounds are connected to earth ground, MH they are still isolated but the earth connection to chassis could be considered the "water pipe next to the meter) would allow continuity to pass.

If the connection was dirty and under normal circumstances there should be zero current flow here then no big deal, but in the event of a surge and depending n where the surge suppressor is connected then there could be a great amount of current flow through a small conductor due to the dirt and it blows open like a fuse.

So, disconnect the ground wire repaired above and repeat the measurements as before, if this was the cause the measurements should be the same.

Now, the scary thing is this...how many folks know for sure their "Meter Ground" is good?

For those with suppressors installed, where is the Meter/Safety ground

[RV Wizard]

Be sure to inspect, clean if necessary and tighten all connections in the ac distribution panel and transfer switch. If you have a junction box between power cord and transfer switch; do the same. I highly recommend a Surge Guard or similar power line protector.

[RJay]

Sam,
What type of surface were you parked on at your site and was your jacks directly on this surface?