It has nothing to do with tripping a breaker or not tripping a breaker
because of multiple paths. The breaker is always in the hot lead.
Whether the return path is via the neutral lead or the ground (green
wire) lead or both, makes no difference to the breaker.
The ground wire is connected to equipment chassis to ensure that there
is a low resistance return path for a fault that may come in contact
with the chassis. It also keeps that chassis close to earth potential in
case of a fault so that fault path does not include a person in contact
with that chassis and earth.
The neutral and ground (green wire) are kept separate only so that
neutral current does not flow on the ground wire under normal operation.
If neutral current were to be allowed on the ground wire under normal
operation it could raise the potential of a chassis above local ground
due to voltage drop in the ground wire carrying current.
By the way, there can be as many earth grounds of the grounding
conductor as you may like. It doesn't have to be grounded to earth only
at the panel. But the neutral must be grounded to earth only at the panel.
73
Gary K4FMX
ersmar@comcast.net wrote:
> TT:
>
> To do otherwise would split overload return current between the neutral
> and ground wires and delay thermal tripping of the protective circuit breaker
> or fuse at the source. (A 30A breaker sees only 25A of a 50A overload, for
> example, and lets the load (heater?) just sit there and cook until it
> flames.)
>
> 73 de
> Gene Smar AD3F
>
>
>
> There must be no path between system neutral and
>
>>ground anywhere else.
>
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
> questions and ask for Sherman, W2FLA.
>
> _______________________________________________
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>
>
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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