panel bonding from transformer
- Thread starter grumpy11
- Start date
- Status
If you have met the requirements of 250.30 then the Inspector is incorrect.
His reference to 250.92 would not be applicable on a SDS, but the fact that he used that reference indicates that you may be in for an interesting saga,
His reference to 250.92 would not be applicable on a SDS, but the fact that he used that reference indicates that you may be in for an interesting saga,
- Location
- Logan, Utah
I agree with Gus.
There is nothing in 250.30 that requires the transformer to be bonded in accordance with 250.92.
I would guess that the inspector is incorrectly calling the transformer a "service" when it is a separately derived system.
Chris
There is nothing in 250.30 that requires the transformer to be bonded in accordance with 250.92.
I would guess that the inspector is incorrectly calling the transformer a "service" when it is a separately derived system.
Chris
I'm not sure what you don't understand. Sight unseen, we are agreeing with you.
I don't have your reference but here is another:
Perhaps you can show him or his supervisor your reference. He may have simply been having a brain cloud that day.
I don't have your reference but here is another:
Perhaps you can show him or his supervisor your reference. He may have simply been having a brain cloud that day.
erickench
Senior Member
- Location
- Brooklyn, NY
NEC 250.92 pertains to services only. The definition for a service in article 100 is:
The conductors and equipment for delivering energy from the serving utility to the wiring system of the premises served.
Please note that the words "serving utility" is used in this definition. Your system is separately derived and therefore not bound by the rules of NEC 250.92.
The conductors and equipment for delivering energy from the serving utility to the wiring system of the premises served.
Please note that the words "serving utility" is used in this definition. Your system is separately derived and therefore not bound by the rules of NEC 250.92.
cripple
Senior Member
- Location
- Santa Fe, New Mexico
panel bonding from transformer
Section 250.30(A)(1) is very clear as to where the grounded (neutral) conductor on a SDS is to bonded, it states the following;
(1) System Bonding Jumper. An unspliced system bonding jumper in compliance with 250.28(A) through (D) that is sized based on the derived phase conductors shall be used to connect the equipment grounding conductors of the separately derived system to the grounded conductor. This connection shall be made at any single point on the separately derived system from the source to the first system disconnecting means or overcurrent device, or it shall be made at the source of a separately derived system that has no disconnecting means or overcurrent devices.
We installed 3 phase 4 wire with an egc to panel to main cb in panel.
The conductor you noted as egc, should be noted as a equipment bonding jumper (EBJ) which is required to be sized per 250.30(A)(2).
Inspector gave us a violation based on article 250.92 for neutral not bonded.
When quoting code rulers you don?t state article 250.92 the proper quote would be section 250.94 or just 250.94.
Section 250.30(A)(1) is very clear as to where the grounded (neutral) conductor on a SDS is to bonded, it states the following;
(1) System Bonding Jumper. An unspliced system bonding jumper in compliance with 250.28(A) through (D) that is sized based on the derived phase conductors shall be used to connect the equipment grounding conductors of the separately derived system to the grounded conductor. This connection shall be made at any single point on the separately derived system from the source to the first system disconnecting means or overcurrent device, or it shall be made at the source of a separately derived system that has no disconnecting means or overcurrent devices.
We installed 3 phase 4 wire with an egc to panel to main cb in panel.
The conductor you noted as egc, should be noted as a equipment bonding jumper (EBJ) which is required to be sized per 250.30(A)(2).
Inspector gave us a violation based on article 250.92 for neutral not bonded.
When quoting code rulers you don?t state article 250.92 the proper quote would be section 250.94 or just 250.94.
If you bond your neutral and ground at the panel you will create parrallel paths for current. although your EGC will be smaller than your neutral conductor it will carry equal current and may overheat as it is undersized. You will also make your raceway a current carrier. This is a very misunderstood. Treat your trani as a new service and your panel as a sub panel.
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