neutral to ground on power generation

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javiersalas52d

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OK, here is what I have always wanted to know, I need your help. I am a power generation technician in the army and need to know why neutral and ground have continuity between them. On my 15kw generators they can be set for 120/208 or 240/416 three phase. Ground and Neutral have a removable link between them. Here is someting I just can not grasp. If I touch ground, like the ground rod or engine I will not get shocked but if I touch Neutral I will get shocked. Why is this? I mean dumb it down for me. What makes this so hard to understand for me is that neutral and ground have continuity, why don't I get shocked when I touch ground? Shouldn't electricity take the path of least resistance? . I had a generator that burned up a ground wire and I can't figure out why. I have since fixed the wire and checked for other faults and found none. I have since run the generator for 234 hours at 45 to 85% load with no problem. Need some help in Iraq
 
Re: neutral to ground on power generation

If the generator is used without being connected to a transfer switch, then the neutral to ground jumper is installed and ground rods are driven.

What is the voltage and output of the generator?
IE 120/240?
single phase?
three phase?
 
Re: neutral to ground on power generation

Originally posted by javiersalas52d:
need to know why neutral and ground have continuity between them. Ground and Neutral have a removable link between them. If I touch ground, like the ground rod or engine I will not get shocked but if I touch Neutral I will get shocked. Why is this? Shouldn't electricity take the path of least resistance? .
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Your generator has a removable link between N-G so the generator can be configured as either a separately derived system (SDS) or not. A SDS is determined by whether or not the neutral is switched or not by the Automatic Transfer Switch (ATS). So if the neutral is not switched (non SDS), you remove the link anf the neutral is bonded to ground at the service. If the neutral is switched (SDS) then you leave the link in and bond the Xo of the generator to the facility ground electrode system.

In either case the neutral will not shock you if properly installed and bonded to ground.

Now to clear up something. "Current takes the path of least resistance" False! Current takes all paths available. The path with the least resistance carries the largest amount in compliance with Ohm's Law.

My question back to you is the generator being used as a back up source to a utility supplied service, or a stand alone source?
 
Re: neutral to ground on power generation

The generator is stand alone, skid mounted. It has wires hooked up to the load terminals, that lead to a panel box I aquired. It is pretty balanced out at about 75% L1, 80% L2, and 72% L3 when running during the day. I have three phase and single phase. It has a ground fault indicator at the only convience recepticle. I appreciate your help. This issue is the one of the only issues I have trouble understanding on my generators. The reason why I ask is because I had a generator at another site that I went to do maintenance on and I discovered it had a burnt ground wire. The wire went to The ground terminal that is joined by a bar connecting it to the neutral. The only thing I can think that happened is that the operator hooked up a load to A hot wire and ground or they didn't ground it properly. I have since repaired it and did some trouble shooting to check for shorts or other damage. No faults found. I have since used it for over 234 hours with 50 to 80 percent load with no problem. I have been trying to figure out why the ground wire burned up in the first place?
 
Re: neutral to ground on power generation

I could also use your help in obtaining an nec book, I am a novice at the industry. I work on diesel engines and genrator protective relays and switches but I would like to get more into electrical besides just a generator, like installing a standby system for a house . Can you point me in the right direction?
 
Re: neutral to ground on power generation

I discovered it had a burnt ground wire. The wire went to The ground terminal that is joined by a bar connecting it to the neutral.
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I'm not sure which wire you mean by the "ground wire", the neutral conductor, the equipment bonding conductor, or the system grounding conductor.

The neutral could be overheated by the excess harmonic currents caused by non-linear loads.

The system grounding conductor could be overheated by a lightning strike or inadvertant contact between the generator conductors and the conductors of another grounded system.

Ed

[ June 25, 2004, 09:30 AM: Message edited by: Ed MacLaren ]
 
Re: neutral to ground on power generation

[/QUOTE]I'm not sure which wire you mean by the "ground wire", the neutral conductor, the equipment bonding conductor, or the system grounding conductor.

It was the system grounding conductor, it haD A wire coming off of it leading to a ground rod. The neutral or neutral conductor has a removable link in between it and the generator ground terminal, the one that has a wire attatched to it leading to a ground rod.
 
Re: neutral to ground on power generation

the ground wire taht burnt up went from the earth ground terminal back to the starter of the generator.
 
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