Grounding a Neutral

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gabe044

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I know that you sometimes need to connect the neutral and ground wires together. Just trying to figure out how exactly this works when you connect these together. Any insight would be great. Thanks
 
They are connected together at every service disconnect and at every separately derived system.

The reason is that the grounding conductors and neutral conductors are connected together is that they must make their way back to the source. This is done via the grounded neutral conductor connected back to the source transformer or generator.
 
While I understand this is confusing for many electricians and I am not wanting to see your question answered,. But, I would assume that most likely you may have other questions and or confusion regarding grounding practices. I would suggest you obtain a few books on this issues, Mike Holt has a good book and then there is the Soares book on grounding.
Both should be in every electricians library.
 
gabe044 said:
I know that you sometimes need to connect the neutral and ground wires together. Just trying to figure out how exactly this works when you connect these together. Any insight would be great. Thanks
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The neutral must bond at the service disconnect and at a separately derived system (transformer...). In these cases the neutral really has two functions: 1) return path for the unbalanced load, 2) ground fault path (shorts path). And basically it's a rarity to bond the neutral any other time.

Think how the neutral carries the return load back to source, and if the neutral is broken the circuit is dysfunctional. Think also that the return neutral load will fallow ALL paths back to its source (usually the 'XO' of a transformer), because of this care must be taken when to bond the neutral to the case frame and equipment grounding conductors otherwise current will flow on equipment grounds throughout the system, in other words current will flow on multiple parallel paths instead of just one intended controlled path (the neutral).

A short to case frame will not open a breaker if the fault path does not exist to source (again usually the 'XO' of a transformer), this path should be a known intentional path not an assumed one. Downstream circuitry should have good bonding and fault paths which in turn culminate at the service disconnect or a separately derived system to enable any fault current (shorts) to the source 'XO', and like a circuit if this is broken it wont work fault current will remain and dangerous touch voltage will exist where it does not belong.

You will not have a ground fault path (for shorts) to earth, and this is a code violation if used (250-4(A)(5)). In the world of premises wiring we have to create a path for fault current to source, fault current paths need the neutral conductor for the route to source this is why we must bond the neutral at the service disconnect and at separately derived systems.
 
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