Open-ground hazard
My AC Line Meter indicates "Open Ground." What are the dangers associated with this condition? Note added: My system is 30 amp and connected to shore power. Shore power is grounded. The AC Line Met...
Forum Discussion
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.
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.
-----------------------------------------------------------------------------------
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.
