Question pdf

[codequestion]

In the attached pdf, I am brining in trough 5 sets of #4 600 AL. I have 1600 amps main service disconnect that is grounded with main bonding jumper in the 1600 amps disconnect. What size ground conductor and NEC table should be in trough so that it can be tapped to individual disconnect and meter with their own ground conductor?

 

[Dennis Alwon]

If you mean equipment grounding conductor then it is either 350 kcm al or 4/0 cu

 

[Dennis Alwon]

Your grounding electrode conductor would be 3/0 cu or 250 kcm al

Your bonding jumper is 400kcm AL

 

[infinity]

EGC is sized by T250.122 based on 1600 amps. The EGC with each feeder tap is not required to be larger than the tap conductors.

 

[codequestion]

Please see attached pdf DOC3. My question is what table you would use to size the ground conductor in the trough? The one that is not tapped and labeled "Ground Size What Conductor? Table to use" in the pdf.

 

[infinity]

Please see attached pdf DOC3. My question is what table you would use to size the ground conductor in the trough? The one that is not tapped and labeled "Ground Size What Conductor? Table to use" in the pdf.

The answer is in posts #2 and #4.

 

[codequestion]

The answer is in posts #2 and #4.

But the conductor in question is it equioment ground conductor or bonding jumper?

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[infinity]

It's on the load side of the service disconnect which makes it an EGC.

 

[Dennis Alwon]

The problem is-- ground conductor can mean anything

The grounding electrode conductor use Table 250.66
Bonding Jumper use Table 250.102
the equipment grounding conductor uses Table 250.122

 

[codequestion]

The problem is-- ground conductor can mean anything

The grounding electrode conductor use Table 250.66
Bonding Jumper use Table 250.102
the equipment grounding conductor uses Table 250.122

What would you use in my situation?

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[roger]

What would you use in my situation?

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Have you read the definitions in article 100?

What would you guess it to be?

Roger

 

[codequestion]

Have you read the definitions in article 100?

What would you guess it to be?

Roger

EGC. However those metersare utility and so is CT cabinet. Utility does not allow EGC pass thru their equipment. Can the trough, panels, Meters, CT cabinet be bonded to 1600 amps main service disconnect which has main bonding jumpers and GEC and not have EGC in trough?

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[Dennis Alwon]

I see the wire in the trough as an equipment grounding conductor sized for the 1600 amp service

 

[electrofelon]

I see the wire in the trough as an equipment grounding conductor sized for the 1600 amp service

I concur, seems straightforward to me. The only variable is where the OP said,

However those meters are utility and so is CT cabinet. Utility does not allow EGC pass thru their equipment.

A few comments on this. First note that is is common to have such utility equipment on the customer side of the service point and sometimes on the load side of the service disconnect. The latter is called cold sequence metering. Generally utilities require hot sequence metering unless there are more than 6 meters. It doesnt matter if it is cold sequenced, you still have the service disconnect as the transition point from bonding to the grounded conductor on the supply side, and separate grounded conductor and EGC on the load side. I doubt the utility "does not allow EGC to pass through their equipment" in such cases.

Note there is 250.142(B) exception #2 which allows load side meter enclosures to be bonded to the grounded conductor.

 

[codequestion]

I concur, seems straightforward to me. The only variable is where the OP said,



A few comments on this. First note that is is common to have such utility equipment on the customer side of the service point and sometimes on the load side of the service disconnect. The latter is called cold sequence metering. Generally utilities require hot sequence metering unless there are more than 6 meters. It doesnt matter if it is cold sequenced, you still have the service disconnect as the transition point from bonding to the grounded conductor on the supply side, and separate grounded conductor and EGC on the load side. I doubt the utility "does not allow EGC to pass through their equipment" in such cases.

Note there is 250.142(B) exception #2 which allows load side meter enclosures to be bonded to the grounded conductor.

250.142(B) says ground meter enclosures by connection to the grounded conductor which is neutral. What would happen to the EGC from service disconnect run in trough thru meter and CTs? How does that work also bonded to the meter or just run thru?

 

[Dennis Alwon]

They make meters that isolate the neutral from the can

 

[codequestion]

They make meters that isolate the neutral from the can

I dont follow you. I have EGC bar and neutral bar main bonding jumper at service disco. I also have EGC and neutral from load side of service disconnect to wireway trough then to individual meters and ct cabinet. How would EGC be connected from load side of service disco to meters and ct cabinets?

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[codequestion]

I dont follow you. I have EGC bar and neutral bar main bonding jumper at service disco. I also have EGC and neutral from load side of service disconnect to wireway trough then to individual meters and ct cabinet. How would EGC be connected from load side of service disco to meters and ct cabinets?

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No one for the above question?

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[infinity]

I dont follow you. I have EGC bar and neutral bar main bonding jumper at service disco. I also have EGC and neutral from load side of service disconnect to wireway trough then to individual meters and ct cabinet. How would EGC be connected from load side of service disco to meters and ct cabinets?

The same way you would connect any metallic electrical equipment, to the EGC run with the 1600 amp feeder.

 

[codequestion]

The same way you would connect any metallic electrical equipment, to the EGC run with the 1600 amp feeder.

I meant in meters and ct cabinet would neutral and equipment ground conductor be bonded together again or is their connection seperate terminial in ct cabinet and utility meters for equipment ground conductor and neutral?

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