Seattle Lion wrote:
smkettner wrote:
Still, get the outlet tester. Still could be reverse polarity as there is no neutral ground bond in the RV.
If there is no neutral/ground bond in the RV, then GFI's wouldn't work. I think neutral in the camper should be connected at the power center to the incoming ground (not earth, the green ground wire on the 30 amp cord). A problem with this conductor going into your camper will let all AC "float", which can be hazardous if some stuff in the camper is not using polarized plugs. A quick way to test this is to look for voltage between neutral (white) and ground (green) at various points in your power chain.
This issue is one reason why it is important to check shore AC before plugging in.
It is important that there is
no neutral/ground bond in the trailer. Again, the only place the neutral should be bonded to the ground is at the campground service entrance. While some metered pedestals are treated as a service entrance and the bond is at the pedestal, it should never be bonded in the trailer.
Why? If you bond the neutral to the trailer's ground you have a parallel circuit. The neutral current will split, part on the neutral wire & the remainder on the ground wire. Since the ground is (or should be) bonded to the trailer's frame, and in the campground, all the metal in buildings, water & gas plumbing, etc they are now carrying part of the neutral current. Believe it or not, you could receive a shock disconnecting your water hose from the campground connection if you have a ground/neutral bond in the trailer!
As to a GFCI, it does not need a ground to work properly. A GFI or GFCI monitors the current in the hot wire & the neutral. If they differ by more than 5ma, it shuts the circuit down. Usually the fault that causes the difference is to ground, but if it was to another hot or a different neutral it would still shut down. Code allows a GFCI receptacle to be used to replace an old 2 wire receptacle without connecting the ground pin connection - it still provides fault to ground protection (see Article 250.130(C) of the 2011 NEC).
Lastly, in a properly wired system there can & usually will be a small voltage between the neutral & hot. The neutral will be carrying current. If it is, there must be a voltage drop across the length of the neutral wire (Ohm's law). Since the ground is not carrying current, even though they are both connected to the same point at the service entrance, at the load end there can (and under load, should) be a difference.