Open-ground hazard

myredracer wrote:
OP needs to provide a bit more info

What additional information would you like?

Its worth pursuing to the point of asking readers for their opinions on this. Thank you road-runner.

MEXICOWANDERER wrote:
Why aren't phase failures discussed more often? Could it be? Neutral bus and conductors are more vulnerable? How would that be possible? Or the succinct question How Would That Be Permissible?

Just a guess here. When we hear of a neutral failure it's usually in the context of fired equipment from too high voltage. A phase failure never results in voltage being too high, drastically reducing the risk of fried equipment. It's more likely for somebody to post "The park power fried my equipment", rather than "The power wasn't right so we had to move to another space". And the subject of the thread, open ground, usually goes undetected until somebody feels a tingle from the RV body.

Dang I can't pull one over on you guys :(

My next step would have been phase phrased differently for simplicity then ktmrfs' succinct reply but I'll press ahead with the fun...

"A shared neutral is a connection in which a plurality of circuits use the same neutral connection. This is also known as a common neutral, and the circuits and neutral together are sometimes referred to as an Edison circuit.

In a 3-phase system it is legal in some jurisdictions to share a single neutral wire between all three (3) phases*. One neutral may not have two “hot” wires from the same phase. It is good practice to use four (4) pole Circuit breakers (as opposed to the standard three pole) where the fourth pole is the neutral phase, and is hence protected against over current on the neutral conductor. Please remember that some jurisdiction prohibit the use of shared neutrals and/or require that the neutral conductor be substantially larger than the phase conductors"

OK, so far so (good) but using circular mil ampacity as a guide how do various (regional) jurisdictions compare? I do not know the answer to this question so I am asking.

There is a method to my madness of being purposefully oblique. Another question must follow -- the ratio, the % of neutral failures in relationship to L1 and L2 failures with regard to terminals and fixtures.

Nothing is "by accident". Predominance of one factor over two others, all thing being (supposedly) equal is illogical when large sampling has been conducted.

On one extreme there is ktmrfs whom I must beware of in trying to pull future "fast-ones" on the other hand there is the majority who may need to have this spelled out plainly.

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You have read numerous accounts of pedestal and cord failures. You have heard innumerable accounts discussed in person (I would imagine). Failures involve connections and integral wire terminations. why neutral? Why aren't phase failures discussed more often? Could it be? Neutral bus and conductors are more vulnerable? How would that be possible? Or the succinct question How Would That Be Permissible? We have NEMA we have NEC. Then we have differing regional neutral ampacity regulations.

Fascinating...

*This is completely dependent on transformer configuration. A DELTA 3-phase transformer can more easily support a single neutral. We have WYE transformers here and the neutral issue is much more prevalent. Part of the reason my SOLA ferroresonant line regulator creates its own neutral via a 2 to 1 step down.

OP needs to provide a bit more info., but to summarize the potential risks of an open ground in no particular order:

- death
- mild to painful shock
- fire
- damage to electronics

wa8yxm wrote:
EXCEPTION: If the outlet is GFCI protected.. The ground may be open on purpose as the GFCI will provide protection.

Pls say more. I think the new outlet is on the same circuit with an outlet with GFCI protection.

If the existing outlets test normal and your newly added outlet has no ground.... FIX THE GROUND CONNECTION on the new outlet.

The hazard is electrocution during a fault.

Ah Open Ground.. Ok, The safety ground is there for your safety.. Now. understand I am typing from EXPERIENCE.. Painful Experience.

Imagine you are holding a metal cased tool (Skill hand grinder) and there is an internal short. Hot to case (There was) Now the case is HOT.

Mains power is grounded, the neutral is bonded to ground at the pole and again at the service entrance so the Ground offers a return path.

And YOU are part of that path (I broke a few grinding points with that thing and finally went out and bought a Dremel of my own (It belonged to my boss)

Now I just suffered some pain.. But if I'd had that in the other hand....
The human body is ALMOST but not quite symeterical (Two halves mirrored)

Example you have a right hand and a left hand

But the HEART is a bit off center (To the left) Had I had that tool in my LEFT hand (I can use either hand) the current path would have been right THROUGH my heart and I might well NOT be typing this today.

And that folks. is the danger of an open ground...


EXCEPTION: If the outlet is GFCI protected.. The ground may be open on purpose as the GFCI will provide protection.

MEXICOWANDERER wrote:
A Little Test

3-wires

L1 load 10 amperes
L2 load 10 amperes
L0 load (?) amperes

SURPRISE

if L0 is the neutral, and L1 and L2 are 120V legs of 240 and the load is resistive L0=0 amps L2 and L1 out of phase 180 degrees and cancel.

when L1 is +10A, L2 is -10A

Need to use vector not scalar math.

A Little Test

3-wires

L1 load 10 amperes
L2 load 10 amperes
L0 load (?) amperes

SURPRISE