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Post Info TOPIC: Neutral vs ground


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Neutral vs ground


I'm confused and the more I try to figure out why, the confuseder I get.

I keep reading that all load centers (breaker boxes) are supposed to not only have a ground bar, but a neutral bar - but both are grounds. HUH!!!

My home is 41 years old, it has three wires coming through the main breaker - 120/120/ground - no 4th wire that could be called a neutral. Over the past 18 years, any changes I've made have all had that shiny uninsulated copper wire hooked to the ground bar, just like I was taught. Just now tracing some that "others" have done, well they went to the neutral bar or maybe even the ground bar. There are several articles (many!!) on line that say that the neutral must be used but, oh well, if you have an older home, maybe it isn't even there and you really don't have a problem because they are both grounds anyhow and are "bonded" in the box or somewhere before the ground rod. WTF!!!

Sorry if I rant - but to me on a 220VAC home system, a ground is a .... ground. Nothing is neutral



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Dave W (Irelands Child/IC2)

Quando omni flunkus, moritati (When all else fails, play dead - R Green)



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Are you sure that center bar in your fuse box is grounded Dave?.......I am no electrician, but I am sure mine has that center bar (neutral) and a separate ground wire

Maybe I am misunderstanding what you are saying

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I think I've managed to confuse you with my rant. My breaker box has a ground bar AND a neutral bar. They both are grounded and the original installer used them interchangeably. To have a full neutral, and from what I'm digging out, you need a 3 wire plus ground for the entry wire - 120/120/N/gnd. The older home systems usually didn't have a separate neutral - unless they went to 3 phase. As far as what you have, it's governed by CSA and that's another bag of worms to us sutherners



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Dave W (Irelands Child/IC2)

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I havent looked that close at by panel in my basement....I just assumed that the neutral would be separate than the ground.....will have to take a look....I know there are 3 wires coming into the house.....I think....lol

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RUMBLER ,,,,,,,, WHERE YA AT WHEN DAVE NEEDS YA??????????

YA HOO,,,,,,,,,,,,confuseconfuse



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Sorry gents, I had a bit of a hitch in my getalong - computer went belly up when we moved.

Dave, it can be a confusing thing for a non-electrician, and many electricians, too.  There is a definite difference between a GROUND and a NEUTRAL, even though they may be common at some point.

The service coming into your house is two hot legs at 120 volts each, measured to ground/neutral, and one NEUTRAL leg that is grounded at the pole and at the service panel.  In the panel neutrals and grounds are terminated on the same terminal bar, and the bar is bonded to the panel box through the screws that hold it in place, and the whole works is tied to a ground rod driven into the ground, or to a metal water pipe that is buried in the ground, or to a re-bar poured into the foundation called a "trimmer ground".  In order of preference as to the best setup, a driven ground is best.  This whole lashup provides a path of return to the grid system that feeds the service to your house and others.  In that service panel is the only place in your house where neutrals and grounds are common; the neutral in a circuit in your house provides a dedicated path of return for the circuit operation, and the ground provides a path for short circuit current to protect the circuit in case of an accidental short of some sort.  If you short a hot leg to the neutral, it will trip the circuit breaker on OVERLOAD,  high amperage.  If you short a hot leg to the ground, it will trip on GROUND CURRENT at a much lower amperage.  Depending on the distance from the common point of connection, there is little difference in how one will trip over the other, but farther away from the common point, a short to ground will trip faster than one to neutral.

In the wiring of your house, any box should normally have three wires feeding IN to the box, a black (or possibly red), a white, and a bare or green insulated; the black is the hot leg (120v), the white is the neutral, and the bare wire is the ground.  Grounds and neutrals should not be connected together at any point other than in the main service panel; if you have sub-panels, there should be two separate terminal bars, one for neutrals, and one for grounds; the ground bar will be bonded to the panel box by its screws, and the neutral bar will be isolated from the panel box and the ground by an insulating bracket of some sort.

Now, when we start talking 220 volts, things change, but remain the same.  Those two 120v legs coming into your house will have a voltage reading between the two hot legs of 220/240v, but will measure, each, 120v to neutral or ground.  When you connect a device such as a range, dryer, or certain other equipment that may have both 220 and 120 volt requirements to operate it's various sub-systems like an oven light or rangetop outlet, there will be a four wire feed to that piece, of equipment, two hot legs, a neutral, and a ground.  If you are connecting something like a 220v motor, you only need three wires, two hot legs, and a ground, since there is no 120v demand in the circuit.

So, that's it in a nutshell, of sorts.  The neutral is a circuit conductor; the ground is a safety device.



-- Edited by Rrumbler on Thursday 5th of January 2012 03:44:26 PM



-- Edited by Rrumbler on Thursday 5th of January 2012 09:04:54 PM

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Rrumbler - after looking at several explanations on the 'net, that one of yours is the by far best explanation of neutral vs grounds. The very last sentence was what finally turned my 'lights on' then the rest above it made sense.

Thanks for the education. My main box is fine, but will have to look at the 30A sub-box



-- Edited by Dave W on Friday 6th of January 2012 09:15:52 AM

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Dave W (Irelands Child/IC2)

Quando omni flunkus, moritati (When all else fails, play dead - R Green)

WT


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Can't add much to what's already been posted except that you may want to wear arc flash gear even when working on residential panels and there should be continuity between the metal water pipe coming into your house and the electrical grounds in your house.

And inside the load center it may be hard to figure out what is electrically connected by busbar and what is electrically insulated.

Depending on what test instruments you have you can pretty much figure out where the current is going and where it is suppposed to go.  Generally, you don't need a micro ohmmeter to run most tests.



-- Edited by WT on Tuesday 10th of January 2012 04:49:59 PM

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Way back in Dec. 2011 and why I opened this thread was to install a service disconnect and a generator connection panel. I finally did it today, October 15 2012. Can we say pro-cras-ti-na-tion?? Super easy hookup that would have been even easier if Gen-Tran had tightened the plug ground screw so it would have worked the first time I tried to use the generator to run the 'essentials'. Oh well - it works, the generator started after several months of idleness and now I need to take a rest (that is, put away my tools - again!!!)



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Dave W (Irelands Child/IC2)

Quando omni flunkus, moritati (When all else fails, play dead - R Green)



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Pro-cras-ti-na-tion?? Nawwww, I would call it detailed planning and organizing so as not to fry your butt when pursuing said honey-doo !

When my neighbor wired my breaker for my shop a couple months ago, the more I watched him the more "confuseder" I became so I quit watching.

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I installed a 3 way switch and survived....all is good.....lol

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I had to do some remedial work - one entire bank of receptacles wouldn't work after moving wires around in the box. Pulled everything apart, started over, then found a broken wire on a breaker that wasn't even through the bypass box that I evidently broke just moving wires around and it was hidden below the other rat's nest of wires. One thing I did find out is that the generator has plenty of uumph to run the items I want it to - it's a Chinese made 3600watt inverter type. And that breaker box - whoever did the original house wiring - really didn't keep track of what circuits went to where. There are some receptacles in one corner of the first floor that are connected to teceptacles in the opposite corner of the second. I've tried to trace these all down in the past, but can't handle that level of frustration



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Dave W (Irelands Child/IC2)

Quando omni flunkus, moritati (When all else fails, play dead - R Green)

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