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-   -   Ground / neutral reverse. Important or not? (http://www.diychatroom.com/f18/ground-neutral-reverse-important-not-23393/)

Deck 07-08-2008 11:07 PM

Ground / neutral reverse. Important or not?
 
I've googled and some people think this is important and some not. Part of the problem with googling is I get posts from electricians in other countries. For those of us in the U.S., can someone please explain a ground neutral reverse and whether or not it is a safety issue? Some people say they're technically the same. But technically or not, I'd like to know more about this.


Thanks

Pudge565 07-08-2008 11:15 PM

This is an unsafe condition. First off yea in the main disconnect the neutral and grounds are bonded but only in the main disconnect are the bonded after that point any sub panels must have the grounds and netrals isolated. The reason this condition is bad is that it is against code. The bare or green wire can not be used as a current carring conductor.

Deck 07-08-2008 11:22 PM

hi, Thank you for your reply.

Can you tell me why they are isolated and what could happen if the ground is used as a neutral?

Pudge565 07-08-2008 11:39 PM

Well as to why they are isolated after the main disconnect I don't know but I'm sure that a seasoned pro can tell you. As to what could happen if you switch them, well say you put the ground on the neutral and the neutral on the ground, then you have some work done on the electrical well the electricain sees this and switches them back where they should be, ok so now you have current in some recepticals on the ground so you plug your T.V. into this receptical well it may just fry your T.V. If I am wrong a pro will correct me. Seeing as how I am only a student.

BigJimmy 07-09-2008 12:11 AM

Quote:

Originally Posted by Deck (Post 137351)
For those of us in the U.S., can someone please explain a ground neutral reverse and whether or not it is a safety issue? Some people say they're technically the same. But technically or not, I'd like to know more about this.

Ground does not carry (or is not intended to carry) current other than during a fault. The neutral wire on the other hand always carries current, equal to the magnitude of the current in the hot conductor (Chris75: should I talk about GFCI's here??!). The ground conductor is typically connected to the parts of the appliance or device that you can touch. The idea is that there will be 0 volts difference between what you can touch and the ground that you're standing on. If the ground conductor was carrying the neutral current, there could be some voltage rise that could create a shock hazard.

There's a lot more, but this is the poop in a nutshell!
Jimmy

theatretch85 07-09-2008 12:17 AM

It is most definitely a safety issue, pudge is on the right track with this subject.

It is true that the neutral and the grounds are one in the same at the service disconnect but only at the service disconect. These conductors are NOT interchangeable once they leave this panel and cannot be combined/wired together in any way.

If you use a ground as a neutral terminal, what you are doing is energizing the grounded terminal. Which means that any outlet or point at which that ground wire makes contact with another device, you have the potential for a person to become the path to ground. Lets say the ground wire happens to have a loose or bad/broken connection; anything plugged into that circuit with a metal chassis (and even those that don't) can make you the path to ground just by touching the metal frame. Say for instance this is a microwave in your kitchen and you happen to be touching the outside of the microwave and the sink at the same time when making some popcorn. It will be quite the shocking experience.

The reason the neutral and grounds are kept separate once they leave the main service disconnect (usually main breaker panel) is based on the same theory as above. If you tie the neutral and ground together you are allowing return energy to flow on the bare ground wire affecting anything connected to that circuit/sub panel. This has the potential to seriously injure someone just touching a switch or any bare metal along this path.

I am sure Stubbie or someone will be along to provide some wonderful pictures to illustrate the reasons behind this.

fw2007 07-09-2008 03:15 PM

Besides the obvious reasons that have already been given, there is the issue of computer and electronic equipment.
This equipment is very sensitive, and could easily be fried by having any current at all in the case and internal ground system.

In addition, all of the new surge protector strips will warn and/or alarm when this condition exists, and for good reason.

There could be all sorts of problems related to anything that connects to earth ground via another path, such as cable TV, satellite dish, phone, etc.
You definitely don't want to mess with this. It needs to be done correctly!

FW

jimmy21 07-09-2008 07:27 PM

not to mention it could cause electrolysis on all the metals in your house.

Deck 07-09-2008 07:59 PM

Thank you guys for the information provided, it has more than answered my question!


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