Another ground question

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I think I understand NEC rules on this issue but it leaves me asking myself a couple of questions over and over.
What good is it to run a seperate EGC back to the meter, 120' away, and then to the same lug as the Neutral?
Since the Neutral conductor is bonded to the enclosure and grounded with a rod, POCO installed, were would the EGC terminate and why?
Anywere in the meter enclosure would be effectively the same as just using hot, hot, neutral and then bonding in the house, at least it seems to me.
House has ground rod with #6 copper to ground bar in entrance panel. In my mind it seems like bonding here would make a return path just the same as running the 4th wire.
Worked with electricity for over 20 years in the Army and I just want to get this straight in my head, it's driving me crazy not knowing.
Thanks
 
Normally you would not run an EGC from the metering equipment to the main disconnect. The grounded conductor would provide the function of the EGC. Using an EGC would create a parallel return path for the neutral current. Why are you using 4 conductors?
 
This brings up a question.

Yesterday I had a "courtesy" inspection (per my request). This is in a jurisdiction I don't usually work in. The inspector told me that although he agreed that I am correct in running my wire from the ground rod to the neutral bus in the panel (that is the 1st means of disconnect), the POCO will require me to install it to the meterbase. He suggested that I just split-bolt onto my ground wire outside the panel and run it up to the meterbase.

I believe that would be improper since you would have a 2nd path for current from the main panel to the meterbase (one on the neutral and one on the ground wires that are attached to the ground rod). Thoughts?

BTW, this is a 600-amp single-phase outdoor service with no other grounding electrodes.
 
I believe that would be improper since you would have a 2nd path for current from the main panel to the meterbase (one on the neutral and one on the ground wires that are attached to the ground rod). Thoughts?
Multiple connections and parallel paths are permitted by the NEC on the line side of the service disconnect.
Don
 
Chief,
Let me see if i can give a brief explanation.

The neutral conductor carries current under normal circumstances.
The EGC carries current under fault conditions.

Let's use a metal drill with a three pin plug as an example.
The Hot and Neutral conductors enter the drill and are connected to the switch and motor. Both of these conductors are insulated from the case. The EGC is connected to the case.

Now, let's imagine that there is an insulation failure on the Hot conductor. The Hot conductor comes into contact with the case of the drill. If the case of the drill is not connected back to the source, the circuit breaker will not trip and the drill case will stay energized. If you are holding this drill, and some part of your body has a good connection with ground, current will travel through your body and back to the ground rod at the service location, making it's way up through the bonding jumper and back to the source. Electricity does not seek a path to ground, but, sometimes, it uses ground as an alternate path to get back to the source.

So, the EGC is the path back to the source for fault current.

Eric
 
chiefrider007 said:
What good is it to run a seperate EGC back to the meter, 120' away, and then to the same lug as the Neutral?
That's not normally done, unless the service disconnect is at the meter, in which case the connection should actually be made in the disconnect enclosure. Even then, the fourth wire is optional.
Since the Neutral conductor is bonded to the enclosure and grounded with a rod, POCO installed, were would the EGC terminate and why?
Same place (separate lug, of course.)
 
Thank you all, I really mean it. The not knowing of it bothers me more than anything and I'll explain what's going on here as quick as possible. First, I didn't mean that the EGC would be connected to the same terminal as the Neutral, rather that electrically they are the same inside the meter enclosure.
I have what's called a Farm Loop around here. POCO installs meter, 200 amp breaker, secured for their sake, and below that enough lugs to run power to the house and other buildings. Of course they charge for this and it's the normal way for them to provide service.
I ran 200 amp service to house and 100 amp to my barn. All cable is hot, hot, neutral. When in the planning stage I contacted the POCO to ask who, what, when, were, and why (5 W's, military term). I did this to ensure that I met their requirements. All cable was purchased right from them and ran just as they told me except for the fact that I not only buried it but I put in in PVC for safety reasons and longevity. Barn works fine, hot, hot, neutral, ground rod at entrance panel bonded to neutral and ran seperate ground and neutrals from that point. No problems. Flash forward three years, purchase double wide, pad with footings complete with hot, hot, neutral already installed three years earlier. Set up home and one breaker trips. Their electrician and helper ended up cutting out a branch line and running another cable, didn't really repair, just limped it along.
Well it's about this point when they tell me that I'm supposed to have 4 wire, no bond at house panel. It doesn't add up to me so I bond it anyway and later we did overload a circuit in the kitchen and the breaker tripped. Anyway, I keep calling and telling them that ever time the furnace or the frig kicks on the lights blink. Here comes their electrician again and tells me that it's because of the long distance from the meter pole, 120', causing a momentary drop in voltage, 10+Volts, and the fact that the furnace is drawing nearly 90 amps. This doesn't add up to me, I installed lateral per POCO rules. I then called POCO, they came out and put in a new transformer, the old one was only three years old, and I still have the problem. Furnace man checked furnace and says there's nothing wrong there.
This entire time I'm thinking that there just has to be a problem with the neutral somewere and I suspect that there's at least one branch circuit in the home with a loose or open neutral. I tell the company we bought the home from my suspicions and the fact that they should have my wiring troubleshot properly. I might as well have been telling the trees out back.
A couple of months go by and the microwave quits. Just to make sure I checked fuses and such inside the oven and all was good, outlet checked good as well, so I buy a new one.
Almost there everyone. I keep on about the flickering lights and tell them that the home should be bonded, they say that if I bond it they won't warrant it. They also tell me not to do anything until they talk to the POCO about the installation. I'm mad, like to do things right one time, not over and over. I told them that I want it right and will just install the EGC. Then they said, no, just wait until we get back with you.
Now it's three weeks later. Power went out Thursday morning a couple of times and the wife and I are setting around, she's home sick, waiting for power to come back on when all of a sudden the smoke detectors start screaming. I naturally ran to the breaker box to see if one tripped and she headed out looking for smoke. Next thing she's screaming the TV in the bedroom is on fire, I run in, jerk the power cord and carry it outside, smoking like Indian Talk. Come to find out DVR and TV are blown on that outlet. Another outlet in the bedroom blew a cordless phone. Further investigation found another cordless blown in room next to kitchen, a nearly brand new microwave in the kitchen, yeap again, and computer in yet another bedroom blown. All this time and not one breaker in the entrance panel tripped, the only one was a GFI in the kitchen, not to the microwave, and it has two additional outlets connected to it downstream in the kitchen.
I know, run, get out, save yourself and your loved ones. My heart is still racing worried about fire inside the wall. Anyway, all outlets still work and unless I said something most people wouldn't even know. I've worked it for years and can still smell it. Wife says it's just in my nose but I know better.
Rules say mobile, 4 wire. I say it should be bonded in the house but, I had to take that out for warranty purposes.
Now what do you all think? Don't hold back, just let me have it. I think EGC would create parallel paths, not good, should bond it but, rules are rules.
Thanks again for everything.
 
chief,
Bonding or not bonding, 4 wire or 3 wire has nothing to do with this...you have a problem with a neutral connection.
Don
 
Thanks everyone, that's exactly what I think too, a problem with the neutral some were. What do I do to figure out which one is the problem? I could probably figure there is something wrong with the outlets that are blowing appliances and TV's/equipment, right?
I also know the outlets and swithces are not wired to the screw connectors, which is not the way I was taught to do it best.
 
Almost simple.....
You have a bad neutral connection on a multiwire circuit You lost the neutral & it caused a 240 volt condition that caused your TV to melt.
You need to check every possible neutral connection & you should find one melted or melting.
If you can't locate this then you have a bad wire in A CONDUIT or a wall.
 
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