System bonding jumper

[Jpflex]

If the poles and pole mounted transformers are located outside, owned by the company I work for but NOT utility and is away from building served, then how to I know if the transformer has the system bonding jumper between grounded conductor and supply side bonding jumper to metal of transformer as well as grounding conductor terminal?

With this being the case I would not normally install a system ground connector in first disconnect/ breaker switch panel. I believe code would allow me to if grounded conductor from transformer was being used as both supply side bonding jumper and grounded conductor neutral, and a parallel path for neutral current was not allowed

 

[JamesGHogg]

Bonding conductor installed at service switch. Bonding conductor connects utility grounded conductor with grounding electrode. There's no grounding conductor coming off that pole...

 

[augie47]

You would supply a SBJ at your1st disconnect.

 

[Jpflex]

You would supply a SBJ at your1st disconnect.

The reason for this post was because my book says that if the source of a separately derived system (transformer) is located outdoors, then the SYSTEM BONDING JUMPER must be located at source see pic

 

[Jpflex]

You would supply a SBJ at your1st disconnect.

The reason for this post was because my book says that if the source of a separately derived system (transformer) is located outdoors, then the SYSTEM BONDING JUMPER must be located at source see pic

Bonding conductor installed at service switch. Bonding conductor connects utility grounded conductor with grounding electrode. There's no grounding conductor coming off that pole...

there is a grounding conductor running along the pole to a ground rod. The grounding conductor was later connected to transformer

 

[augie47]

250.30(A)(1) Exception 2 states:
Exception No. 2: If a building or structure is supplied by a feeder from an outdoor separately derived system, a system bonding jumper at both the source and the 1rst disconnecting means shall be permitted if doing so does not establish a parallel path for the grounded conductor.
and, in doing so....
250.30(A)2) Exception states:
Exception: A supply-side bonding jumper shall not be required between enclosures for installations made in compliance with 250.30(A)(1), Exception No. 2.

This is what I normally see on outdoor SDS.

As far as the SBJ on your pole transformers, someone with experience will need to address confirming it's existence. I've dealt with very few pole transformer SDS systems. I assume the ground connected to the transformer you mentioned took care of that but that is an assumption.

 

[Jpflex]

Exception 2 if a supply side bonding jumper is not required between enclosures, then they won’t be bonded according to another NEC code. unless your using another exception I’ve found to allow the grounded conductor neutral to be bonded to source and first point of disconnect to ALSO serve as the supply side bonding jumper. In this case you would not install another supply side bonding jumper because it would provide a parallel path for neutral current

 

[augie47]

Exception 2 if a supply side bonding jumper is not required between enclosures, then they won’t be bonded according to another NEC code. unless your using another exception I’ve found to allow the grounded conductor neutral to be bonded to source and first point of disconnect to ALSO serve as the supply side bonding jumper. In this case you would not install another supply side bonding jumper because it would provide a parallel path for neutral current

Exactly what my Post #7 states

 

[Jpflex]

Exactly what my Post #7 states

I’m new to these terminations setups and having to do this at work. The confusion is whether the transformer has the system bonding jumper internally so I don’t have to install one at the first point of disconnect

 

[augie47]

The transformer should have a SBJ per 250.30()A)(1).. IF there is no SSBJ per the exception then the disconnect should have a SBJ

 

[Jpflex]

The transformer should have a SBJ per 250.30()A)(1).. IF there is no SSBJ per the exception then the disconnect should have a SBJ

Ok thanks, by SBJ I’m sure you mean internal transformer system bonding jumper but not supply side bonding jumper

And the grounding conductor is required to be connected at the point of the system bonding jumper then to a grounding electrode for the outside transformer

Additionally one additional supplimental grounding electrode would be required at the first point of disconnect to the building. Does this sound correct? There are no water pipes or structural metal electrodes known at this time so I’m assuming to use a standard ground rod

But if so how does all grounding electrodes become bonded to make one grounding electrode system since there will be two grounding electrodes without a supply side bonding jumper between first point disconnect enclosure and transformer grounding conductor?

Would there have to be a tie point or a bonding jumper between both electrodes? Thanks

 

[augie47]

It's no different from hundreds of thousands of services other than they are your transformers.

 

[Jpflex]

It's no different from hundreds of thousands of services other than they are your transformers.

However utility has their own rules as opposed to following NEC code. Their grounding for example may or may not follow NEC for entirely different reasons

 

[augie47]

Gosh, I didn't know that

 

[Jpflex]

Gosh, I didn't know that

Dam dude why so much sarcasm sheesh