Seperating nuetrals and equipment grounds.

[wormy]

Can someone explain why when you leave a main panel with a feeder to a sub panel from that point on the nuetrals and equipment grounds must be seperated? The are still all tied together in the main panel.

 

[iwire]

Because tying them together in more than one place puts current on items that should not be carrying current.

It can also present a shock hazard when someone decides to use the neutral as a grounding means. Under certain conditions you can energize all the parts that should be at the same potential as ground.

 

[dicklaxt]

It also gives you a more defined fault path back to the voltage source.

dick

 

[mcclary's electrical]

Bob nailed with the "in certain conditions".
If somehow the grounding conductor that is illegally being used as a grounded conductor becomes loose or open, then the normally non current carrying parts of everything that is using that grounding conductor, will become energized to line voltage. Not good

 

[infinity]

Here's a graphic from Mike:

 

[buzzbar]

Thank you all for explaining an often misunderstood condition. A lot of times we know how to do things, but don't often know the 'why'.

Andrew