Proper Grounding of 120V input

[bryanl]

Caveats and caution. There is some information in this thread I'd be very careful about. Here's a recap of what I think is the good stuff.

Generally, hot and neutral are completely isolated from equipment grounds in all equipment.

Neutral is only connected to equipment grounds at the service entrance, which is where the meter is if on grid or where the genset is if using a somewhat permanent genset installation. This is also where the earth ground connection is established.

A portable genset won't usually have any connection between neutral and equipment ground. The hot and neutral are isolated. This means that the only voltage of any note (that will produce current) is in a path between neutral and hot. That would require two failures to obtain accidentally or improperly.

If you are using one of those three indicator light gadgets, you get two lights when on grid or permanent genset: hot to neutral and hot to ground. This is the way you can check any 110v grid power plug, including the 30 Amp RV plug.

On a portable genset, you should get only one indicator light between hot and neutral. This is unless your portable is wired as a permanent installation which would then have hot to ground indicator light, too (and an earth ground). You generally don't want portable gensets to have neutral and ground bonded together as that reduces the number of failure requirements to create potentially hazardous situation.

On a 50 Amp RV service, you'd have double the indicators of a 110v service plus the added double voltage between the two hots.

You don't normally want multiple earth grounds as that can create voltage differentials and unintended current damage in lightning strike situations.

As far as trailer grounding through jacks and such, forget it. That usually doesn't have a low enough impedance to be of any use other than maybe some static bleed-off

If in doubt, check the code. There is a chapter on RV wiring and another on gensets.

[PhilMateo]

Originally Posted by steelbird312

Phil, Are you saying your shore power cord does not have the ground wire grounded to the trailer anywhere, and that the trailer wiring is not connected to the trailer either?
If it were mine, it would be tomorrow! Since that is the way new ones are wired aas well as houses, etc I would want mine the safest it could be!
Some will reason that the jack as well as the stabilizers will effectively ground your unit but I'm skeptical about that.

The "shore power cord" is not grounded....the green wire is cut and capped.

There is a bank of 110V green grounds from each trailer outlet, wired to a wire block, and that is connected to the trailer body. Since the trailer body is the ground for 12V, I assume I have to reconnect the ground to this block, and not the trailer body.

Correct?

Phil

[PhilMateo]

Originally Posted by Over59

Three wires come from the cameground hookup, hot, neutral, ground. They need to stay separate in the trailer. Disconnect the AC and look inside your AC fuse panel. Are the neutral and ground connections common, that is are they connected electrically? Is there a third wire in the outlets. If not, prehaps someone modified a two wire system by adding grounded receptacles and grounding directly to the trailer. If so and your trailer is not connected to the service ground when plugged in at the campground I would fix it before using it again, the trailer could become hot and you become the ground when you touch it. The additional problems is how the fuse panel is mounted. Is the neutral electically connected to the trailer shell via the mounting. The neutral and ground "float" in a trailer and only come together out in the service panel at the campground, not in the trailer.

AC fuse panel? Do I have one? I saw a wiring box, but no fuses. I have an Armstrong Bay Breeze.

All the outlets have 3 wire.

I think I need to rewire box and look for AC fuses.

[PhilMateo]

Originally Posted by Beginner

Our Trailers:

GREEN WIRE: Connects to the Ground Buss in the Circuit Breaker Box. This Ground Buss MUST be connected to the Frame/Skin of the trailer, if not, it is possible (probable), in the event of a short(black wire comes in contact with the skin or an appliance shorts out) that the skin of the trailer could have 120 V on it. In short (no pun intended) if you touch the trailer barefoot, you will get shocked.

So this means that the main power cable from shore or generators should have ground wire attached to the ground buss, where all the 110V appliances and outlets are also grounded? Should this ground buss be attached (grounded) to the trailer shell as well (like the 12V lines)?

[Beginner]

Yes it get confusing.
The Green Wire should be connected to the frame/shell of the trailer.
This Green Wire in the Campground Circuit Breaker box should be sonnected to the campground's Grounding System.
Most campground shore power boxes I've seen have standard 120V recptacles. Plug your tester into that and read the results in accordance with the legend on the device itself. That is a whole lot better than nothing. I very strongly advise getting an adapter that you can plug into the 30 or 50 amp recptacle and plug your tester into. The 50 amp adapter should have more than one place to plug into so that you can check both sides of the 120V. That is a whole lot safer.