GEC Cannot be Green or White

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kwired said:
What is the choke effect when it is carrying current from a lightning event?

I do agree that it is probably not an issue with normal AC current that is present at about any time.
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Lightning is a high frequency high energy event, when you run a conductor through a ferrous metal race way it becomes a short circuit to high frequency AC current and can cause extremely high currents to build up in the raceway that can cause a fire, a choke in this sense is like a transformer with its secondary shorted, apply DC to the primary and nothing happens but apply AC and a higher lever of current tries to flow, many DC applications will use a 1:1 transformer with windings rated for the loads current, each side of the transformer is placed in series with each supply conductor, lets say you have an A winding and a B winding, A1 would be hooked to the supply + wire and B1 would be hooked to the supply - wire, the wires to the load will hook the same way A2 to the + to the load and B2 to the - to the load, any AC that tries to flow in this DC supply choke will be shorted out, choke come in many flavors from a simple couple turns around an iron core to very sophisticated designs that only allow it to pass frequency's below a design level or within a given range of frequency's, by bonding both ends of a raceway you eliminate the choking effect as the conductor and pipe become just one larger conductor.

Another way to think of it and why it got it's name is think of a garden hose, squeeze (choke) it down and it will restrict the water flow in a wire this will cause heat
 
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K8MHZ said:
I can't find the article that specifies the color of a GEC. Plenty on ECG's and grounded conductors. I am probably not looking in the right place.
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Just wait, the way things are going it wont be long before we have to mark them also, wouldn't want someone to mistake a black insulated wire connected to a rod stuck in the Earth and exposed from being a hot conductor, I mean really that would be dangerous if they tried to connect it to an extension cord hot:roll:

I'm so glad I don't work in the country of Chicago:eek:
 
This is a little off topic, but the same subject. Could I ask? Where do you all get "Do Not Remove, Building Ground" tags? The type you would put on the wire at the clamp. Perhaps plastic or metal, green tags.
 
hurk27 said:
Lightning is a high frequency high energy event, when you run a conductor through a ferrous metal race way it becomes a short circuit to high frequency AC current and can cause extremely high currents to build up in the raceway that can cause a fire, a choke in this sense is like a transformer with its secondary shorted, apply DC to the primary and nothing happens but apply AC and a higher lever of current tries to flow, many DC applications will use a 1:1 transformer with windings rated for the loads current, each side of the transformer is placed in series with each supply conductor, lets say you have an A winding and a B winding, A1 would be hooked to the supply + wire and B1 would be hooked to the supply - wire, the wires to the load will hook the same way A2 to the + to the load and B2 to the - to the load, any AC that tries to flow in this DC supply choke will be shorted out, choke come in many flavors from a simple couple turns around an iron core to very sophisticated designs that only allow it to pass frequency's below a design level or within a given range of frequency's, by bonding both ends of a raceway you eliminate the choking effect as the conductor and pipe become just one larger conductor.

Another way to think of it and why it got it's name is think of a garden hose, squeeze (choke) it down and it will restrict the water flow in a wire this will cause heat
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A little there to chew on but I think you are saying it will "choke" lightning current if not bonded to the metal raceway. Maybe because of the amount of energy driving this incident it still won't have too much impact on the outcome of a direct hit, but if you are just in the vicinity of a lightning strike and do still get some surge over lines, maybe it does do you some good to have the raceway bonded.

hurk27 said:
Just wait, the way things are going it wont be long before we have to mark them also, wouldn't want someone to mistake a black insulated wire connected to a rod stuck in the Earth and exposed from being a hot conductor, I mean really that would be dangerous if they tried to connect it to an extension cord hot:roll:

I'm so glad I don't work in the country of Chicago:eek:
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Kind of my thoughts on when I have an inspector that thinks this should be marked with green. If everything else is code compliant how can I ever have a single black conductor that is not even installed in a raceway or is a part of an approved cable method? Why should it matter what color it is period, nothing else is permitted to be run in this manner for the most part, so the fact it is a single conductor run alone kind of should get anyone that is qualified to wondering just what it is if it isn't obvious at first. And if you are at the service equipment it should be fairly obvious that anything landed on the grounded conductor bus is going to be grounded conductor potential no matter what color it is:slaphead: anything attached to a grounding electrode is likely going to be ground potential.

I find this to be about as insane as those that are really adamant about reidentifying white conductors used as ungrounded. I know it is in the code, but is for those that don't know any better. Anyone that knows what they are doing knows that conductor is not grounded if it lands on an overcurrent device. If you are not at the source end there often is still similar evidence that this is probably not a grounded conductor.
 
1. One reason that the choke impedance matters is that with lots of voltage behind it the current will still flow, but with a high enough voltage other alternate paths become accessible and attractive.
2. These days you land neutrals on AFCI and GFCI breakers, just on a different terminal. :angel:
 
don_resqcapt19 said:
Probably because in Chicago they understand, that in the real world, the GEC never carries enough current to actually require the bonding that the NEC requires in 250.64(E). The choke effect is not an issue with currents less than a few hundred amps.
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Or would that just be your assumption since you live in Illinois...;)
 
MasterTheNEC said:
Or would that just be your assumption since you live in Illinois...;)
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Actually based on the fact that the NEC rules for the issues of inductive reactance are very conservative and more stringent that what is supported by the physics. In the NEC 300.20 applies no matter what the current is, but it is not a real world issue until the current exceeds a few hundred amps. The rule in the CEC covering this issue does not apply to circuits with currents of 200 amps or less. I was just extending that idea to the GEC, but I see from other posts, I am not correct when dealing with lighting.

As far as wire colors, the code should be changed to require all wires to be black...then you would at least have to have some idea of what you are doing to work on electrical systems:) it would also take a lot longer to do things and I get paid by the hour:)
 
don_resqcapt19 said:
As far as wire colors, the code should be changed to require all wires to be black...then you would at least have to have some idea of what you are doing to work on electrical systems:) it would also take a lot longer to do things and I get paid by the hour:)
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After that lightning strike sometimes they are all black:)
 
don_resqcapt19 said:
As far as wire colors, the code should be changed to require all wires to be black...then you would at least have to have some idea of what you are doing to work on electrical systems:) it would also take a lot longer to do things and I get paid by the hour:)
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Ahhh..but the COLORS make the world a pretty place :sick:
 
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