GSC Requirement

[enteng14]

Good day sirs,

I would like to ask in what provision in the NEC or NESC that the electric distribution utility is required to provide a grounded conductor to the customer?

many thanks,

 

[kwired]

Good day sirs,

I would like to ask in what provision in the NEC or NESC that the electric distribution utility is required to provide a grounded conductor to the customer?

many thanks,

Wouldn't that depend on if it is a grounded or ungrounded system?

 

[enteng14]

Grounded System

Grounded System

Wouldn't that depend on if it is a grounded or ungrounded system?

Of course it is for a grounded system that i am referring to sir. I know that it is a must for the utility to provide a GSC to the customer but i want to know in what provision from which it was stated.

Thanks

 

[hurk27]

Of course it is for a grounded system that i am referring to sir. I know that it is a must for the utility to provide a GSC to the customer but i want to know in what provision from which it was stated.

Thanks

Utility's are not governed by the NEC. but these are the two provisions that would require a grounded system, and the second is for, where a grounded system is supplied then the grounded conductor is required to be brought to the first disconnect.

250.20(B) Alternating-Current Systems of 50 Volts to 1000
Volts. Alternating-current systems of 50 volts to 1000 volts
that supply premises wiring and premises wiring systems
shall be grounded under any of the following conditions:
(1) Where the system can be grounded so that the maximum
voltage to ground on the ungrounded conductors
does not exceed 150 volts
(2) Where the system is 3-phase, 4-wire, wye connected in
which the neutral conductor is used as a circuit conductor
(3) Where the system is 3-phase, 4-wire, delta connected in
which the midpoint of one phase winding is used as a
circuit conductor

And

250.24(C) Grounded Conductor Brought to Service Equipment.
Where an ac system operating at less than 1000 volts
is grounded at any point, the grounded conductor(s) shall
be run to each service disconnecting means and shall be
connected to each disconnecting means grounded conductor(
s) terminal or bus. A main bonding jumper shall connect
the grounded conductor(s) to each service disconnecting
means enclosure. The grounded conductor(s) shall be installed
in accordance with 250.24(C)(1) through (C)(3).

 

[iwire]

Of course it is for a grounded system that i am referring to sir.

We have to ask the question as we have no idea what you may or may not know.

 

[enteng14]

Utility's are not governed by the NEC. but these are the two provisions that would require a grounded system, and the second is for, where a grounded system is supplied then the grounded conductor is required to be brought to the first disconnect.

Thank you sir hurk for the patience and trying to answer my case. What if the utility did not extend the grounded service conductor at the service point? Can we state the NEC provisions that they should provide a grounded conductor even if the utility is not covered by NEC?

 

[enteng14]

We have to ask the question as we have no idea what you may or may not know.

Hi sir Bob, I just want to know in what provision in the NESC (utility is not covered by NEC) states that the utility must provide a grounded conductor to the customer?

Thank you sir.

BTW, nice avatar sir bob, are you using dranetz products for power measurement?

 

[hurk27]

Thank you sir hurk for the patience and trying to answer my case. What if the utility did not extend the grounded service conductor at the service point? Can we state the NEC provisions that they should provide a grounded conductor even if the utility is not covered by NEC?

I would think if there is a load requiring a grounded circuit conductor, then not supplying it when requested, would be like selling a car and not providing an engine.

we do use a ungrounded system in a very restricted install, 250.21 spell's out these restrictions. but if the install is an ungrounded system, then what the utility uses to provide this, is up to them unless pointed out in the request for power. I have heard of a utility using a 240/139 Y transformer once for an ungrounded install once, but that would be a rare occasion.

There are allot of questions about the install that would determine what and why an ungrounded system was installed.

Here are a few:
What kind of service was requested from the customer at the original install?
What country is this in?
What are the utility standards in that country?

In the US it would be standard to install a grounded system, but it would be a special request for an ungrounded system.

I have read that there are country's where ungrounded is common, but they use RCD's for protection.

so if we know these answers we can say what is or not common to what the utility installed or was requested to install.

 

[enteng14]

I would think if there is a load requiring a grounded circuit conductor, then not supplying it when requested, would be like selling a car and not providing an engine.

we do use a ungrounded system in a very restricted install, 250.21 spell's out these restrictions. but if the install is an ungrounded system, then what the utility uses to provide this, is up to them unless pointed out in the request for power. I have heard of a utility using a 240/139 Y transformer once for an ungrounded install once, but that would be a rare occasion.

There are allot of questions about the install that would determine what and why an ungrounded system was installed.

Here are a few:
What kind of service was requested from the customer at the original install?
What country is this in?
What are the utility standards in that country?

In the US it would be standard to install a grounded system, but it would be a special request for an ungrounded system.

I have read that there are country's where ungrounded is common, but they use RCD's for protection.

so if we know these answers we can say what is or not common to what the utility installed or was requested to install.

Thanks again sir hurk, it does help me a lot.

Actually i'm from Philippines and our electrical codes are somewhat the same with NEC and NESC. Our local utility was using line-to-line system with solidly grounded system. For single phase, 230V Line-to-Line and ground, two ungrounded phase conductors and a ground conductor. These ground conductor is for protective earth only and not use for Line-to-Neutral loads. Our utilization voltage is 230V.

 

[hurk27]

Thanks again sir hurk, it does help me a lot.

Actually i'm from Philippines and our electrical codes are somewhat the same with NEC and NESC. Our local utility was using line-to-line system with solidly grounded system. For single phase, 230V Line-to-Line and ground, two ungrounded phase and a ground. These ground is for protective earth only and not use for Line-to-Neutral loads. Our utilization voltage is 230V.

This clears up some of the things that I was wondering, I kind of felt you were not here in the States, not that it make a difference, but with what the local laws and regulation you might be under compares to what is required here, knowing this helps us to apply what is required better.

I think I can best describe your system as a grounded delta, not at all uncommon for other country's, it is basically a 3-phase delta with a corner ground, we also use in some industrial plants a corner grounded delta system, and the "B" phase is the one we are required to ground, now this same system is also used when a ungrounded delta is requested but in this case "B" phase would not be grounded.

If we do install an ungrounded system the NEC does require a ground monitor alarm system to warn of a grounded phase, as we know it wont open a breaker till the second phase is grounded, this is to allow continued operation till a safe shut down can be scheduled, this is one of the reasons some larger company's will request an ungrounded system.

Again these are only allowed where the installation meets the requirements of 250.21

 

[enteng14]

This clears up some of the things that I was wondering, I kind of felt you were not here in the States, not that it make a difference, but with what the local laws and regulation you might be under compares to what is required here, knowing this helps us to apply what is required better.

I think I can best describe your system as a grounded delta, not at all uncommon for other country's, it is basically a 3-phase delta with a corner ground, we also use in some industrial plants a corner grounded delta system, and the "B" phase is the one we are required to ground, now this same system is also used when a ungrounded delta is requested but in this case "B" phase would not be grounded.

If we do install an ungrounded system the NEC does require a ground monitor alarm system to warn of a grounded phase, as we know it wont open a breaker till the second phase is grounded, this is to allow continued operation till a safe shut down can be scheduled, this is one of the reasons some larger company's will request an ungrounded system.

Again these are only allowed where the installation meets the requirements of 250.21

For single phase, 230VL-L with grounded center tapped.
For three phase, 230V Wye with grounded neutral, 460V Wye grounded neutral and 400Y/230V Wye grounded neutral with line-to-neutral loads.

Were using a local electrical code in our country but i'm still referring to NEC for additional information.

Thanks again sir hurk.

 

[hurk27]

Thanks again sir hurk, it does help me a lot.

Actually i'm from Philippines and our electrical codes are somewhat the same with NEC and NESC. Our local utility was using line-to-line system with solidly grounded system. For single phase, 230V Line-to-Line and ground, two ungrounded phase conductors and a ground conductor. These ground conductor is for protective earth only and not use for Line-to-Neutral loads. Our utilization voltage is 230V.

Ok
I miss read the above in red as to having 230 volts L to L and 230 volts to ground which would be a delta, center tap would be 115 volts to ground

For single phase, 230VL-L with grounded center tapped.
For three phase, 230V Wye with grounded neutral, 460V Wye grounded neutral and 400Y/230V Wye grounded neutral with line-to-neutral loads.

Were using a local electrical code in our country but i'm still referring to NEC for additional information.

Thanks again sir hurk.

those are some strange voltages for Y's to me, but kind of hard to say what is the norm when you never leave your area. its strange your not offered a delta for motor loads as we have here, as with a delta you can loose a utility phase to the transformer and if the loads are not heavy keep operating, as in an open delta.