Service upgrade

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Old 02-10-06, 08:18 PM
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Service upgrade

If I upgrade a 16 space 150 amp main service panel to a 30 space 200 amp main service panel, is it necessary to upgrade the earth ground? We are dealing with a 1350 sq ft single dwelling and adding outdoor and garage circuits to supply a 4HP air compressor, AC/DC welder.
 
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Old 02-11-06, 03:55 AM
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It depends on whether or not it meets today's code.
 
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Old 02-11-06, 04:46 AM
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Originally Posted by Dr. John
If I upgrade a 16 space 150 amp main service panel to a 30 space 200 amp main service panel, is it necessary to upgrade the earth ground? We are dealing with a 1350 sq ft single dwelling and adding outdoor and garage circuits to supply a 4HP air compressor, AC/DC welder.
Basically yes, everything must be upgraded to 200 amp equipment. From the riser and weatherhead to the meter to the panel and grounding/bonding.
Unless of course some of it is adequate for 200 amp already as Racraft stated. I don't think that's likely though.
 
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Old 02-11-06, 09:27 AM
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Originally Posted by Dr. John
is it necessary to upgrade the earth ground?
Yes. An earth ground is another safety device that you hope you never need. But if you ever do, you want a good one. Installing two grounding electrodes isn't a big deal. If your soil is rocky or shallow, there are slightly more involved alternatives.
 
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Old 02-11-06, 11:35 AM
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Originally Posted by bolide
Yes. An earth ground is another safety device that you hope you never need.
Can you explain this? I am of the opinion that ground rods have very little benefit as far as safety goes. They do nothing to aid in opening a breaker.
I know I am not alone in this opinion.
 
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Old 02-11-06, 01:52 PM
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The GEC is not for aiding to trip a breaker.

The purpose of the GEC system is to bring the ground at the service entrance to earth potential.
 
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Old 02-11-06, 02:24 PM
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Exclamation Bonding VS Grounding

Don't confuse bonding with grounding. We bond everthing together so that any fault will cause an Over Current Protective Device (OCPD) to open. We ground the service to limit the voltage to ground from such things as lightning and accidental contact of medium voltage distribution with higher voltage lines.

In order to make this clearer a Code Making Panel is considering changing the name of Equipment Grounding Conductors to Equipment Bonding Conductors.
 
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Old 02-13-06, 12:15 AM
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Originally Posted by Speedy Petey
Can you explain this?
Sure. Were you satisfied with what is already posted?


I am of the opinion that ground rods have very little benefit as far as safety goes.
When it comes to safety, why not have the benefit?


They do nothing to aid in opening a breaker. I know I am not alone in this opinion.
I suspect that everyone agrees with this.


When you see a metal streetlight pole or a meter can on a house, how do you know that you can touch it with risk of shock being unlikely?

The answer is that it must have a local earth ground.
So the GES is there in case something bad happens external to the structure.

It is well pointed out that OCPDs do not protect from lightning - which is high-voltage but low amperage.
The earth-grounding electrode system pushes the potential of the house electrical system up to match the local ground plane analogous to a ship riding over the waves.
This is particularly valuable in the moments before and during lightning strikes as it minimizes damaging potential differences in electrical equipment.

The ground at the transformer is less effective for this function for the same reason that the GES doesn't conduct enough fault-current to trip an OCPD There is too much resistance from the local ground through the earth to the transformer.

As hornetd mentioned, it also offers some protection in the event of other faults including a broken neutral.
 
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Old 02-13-06, 04:34 AM
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Originally Posted by bolide
When you see a metal streetlight pole or a meter can on a house, how do you know that you can touch it with risk of shock being unlikely?

The answer is that it must have a local earth ground.
So the GES is there in case something bad happens external to the structure.
Not exactly.
Ground Rod Does Not Reduce Touch Potential
Ground Rod at Metal Poles a Waste?

While I'm not a theory expert I can interpret and learn from what I read from the experts.


Open neutral? How does current flowing into the ground help with this?
 
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Old 02-13-06, 09:54 AM
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Originally Posted by Speedy Petey
That is a misstatement.
To correct statement is "A ground rod cannot always reduce touch voltage to a safe level".


Originally Posted by Mike Holt
I have no problem with ground rods at the pole if the circuit to the pole is protected with surge suppression, but a ground rod at the pole without surge protection is a waste of time and money.
So surge protection is needed to protect equipment from lightning. A good ECG is needed to protect from a line-to-case fault. There is no neutral to EGC bond in a light pole.


Open neutral? How does current flowing into the ground help with this?
Who said that current is "flowing into the ground"? I sure didn't. (The flow is miniscule.)
The ground rod reduces the touch potential (voltage, not current).
If the neutral is broken, and you measure voltage from the ground rod to the meter pan, what is the reading?
If you disconnect the GEC, what is the reading?

Or if you like, measure the voltage from the pan to your hand in each case.


See, I have this really weird habit of placing the electrodes with a GEC between them just outside the roof dripline where someone would be standing to touch the meter pan.

So the person's distance is 0', not 5'. (The person 5' away is not protected. But of course, he will not have an easy time reaching the meter either.)
 
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Old 02-13-06, 10:04 AM
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I am closing the thread. The original question has been answered.
 
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