Supply side bonding jumper

[hhsting]

I have wire-way in line side of 4 main service discos. The wire has wire one set of 1 set of 4-600 kmil to each of service disconnect.

The engineer has provided what he calls supply side bonding jumper from each service disconnect ground bus to the wire-way enclosure #2/0 awg.

I have the following questions:

1. Is the bonding jumper mentioned from each service disconnect to the wireway enclosure allowed to be in conduit with phase and neutral conductors between wireway and service disconnect or not?
2. Can it be outside the wireway?
3. Should not the wireway be bonded with bonding jumper from neutral to the wire way enclosure in line side instead of supply side bonding jumper?

 

[david]

The supply side bonding jumpers should g
o to the equipment grounding buss.
You need to know if a system bonding jumper is going to be installed.

More detail is needed. I'm saying that because you said the engineer is calling it a ssbj, you seem to not be sure if that is what it is

 

[hhsting]

The supply side bonding jumpers should g
o to the equipment grounding buss.
You need to know if a system bonding jumper is going to be installed.

More detail is needed. I'm saying that because you said the engineer is calling it a ssbj, you seem to not be sure if that is what it is

How supply side bonding jumper go to equipment grounding bus? I dont follow. I have wireway line side of main service disconnect.

Problem is bonding of the wireway on line aide of main service disconnect and CT cabinet.

 

[Elect117]

Supply side bonding jumpers bond the metal enclosures and conduit on the supply side of the main disconnecting device(s) of the service(s).

System bonding jumper and main bonding jumper are the same, where they connect the grounded conductor (neutral) to the equipment grounding conductor and the supply side bonding jumper.

To size the supply side bonding jumper, use 250.102.

Each raceway can have it's own and a bonding bushing should be used (250.92). Or you can install just one for each raceway, and bond it accordingly (250.92).

1. Is the bonding jumper mentioned from each service disconnect to the wireway enclosure allowed to be in conduit with phase and neutral conductors between wireway and service disconnect or not?

The term bonding jumper is vague. Yes it can be in conduit. 250.102(E)

2. Can it be outside the wireway?

Yes. A supply side bonding jumper can be outside of the race way, less than 6' and routed with the conduit.

3. Should not the wireway be bonded with bonding jumper from neutral to the wire way enclosure in line side instead of supply side bonding jumper?

The neutral should not be connected to the wireway. You connect the neutral to the grounding electrode conductor and to the system bonding jumper (or main bonding jumper). Depending on the design and the location, that is most likely inside of the service disconnect. It should come off the equipment grounding conductor bus or terminals. Inside of the service disconnecting means, it can also come off of the neutral bar since the neutral bar and the equipment grounding bar are the same.

 

[hhsting]

Supply side bonding jumpers bond the metal enclosures and conduit on the supply side of the main disconnecting device(s) of the service(s).

System bonding jumper and main bonding jumper are the same, where they connect the grounded conductor (neutral) to the equipment grounding conductor and the supply side bonding jumper.

To size the supply side bonding jumper, use 250.102.

Each raceway can have it's own and a bonding bushing should be used (250.92). Or you can install just one for each raceway, and bond it accordingly (250.92).




The term bonding jumper is vague. Yes it can be in conduit. 250.102(E)



Yes. A supply side bonding jumper can be outside of the race way, less than 6' and routed with the conduit.



The neutral should not be connected to the wireway. You connect the neutral to the grounding electrode conductor and to the system bonding jumper (or main bonding jumper). Depending on the design and the location, that is most likely inside of the service disconnect. It should come off the equipment grounding conductor bus or terminals. Inside of the service disconnecting means, it can also come off of the neutral bar since the neutral bar and the equipment grounding bar are the same.

If you cant bond wireway enclosure which is on line side with neutral then how come NEC 2017 Article 250.80 says you can? How else you ground the line side wireway. Utility only brings neutral and phase.

 

[david]

Making the assumption that the conduits are not pvc.

The engineer is trying not to create a parallel path for the neutral current.

He is having bonding jumpers installed from the service disconnects back to the metal wire way.

The engineer does not want the neutral bonded in the wireway supply side of the service disconnects

How is the CT cabinet bonded?

 

[david]

Making the assumption that the conduits are not pvc.

The engineer is trying not to create a parallel path for the neutral current.

He is having bonding jumpers installed from the service disconnects back to the metal wire way.

The engineer does not want the neutral bonded in the wireway supply side of the service disconnects

How is the CT cabinet bonded?

Since metal conduit is an approved ssbj the engineer might just be doing it that way because it's more convenient to use the 1/0 from the service disconnects. Rather than a larger wire type ssbj from the neutral in the wireway.

 

[wwhitney]

2017 NEC 250.80 requires the wireway to be bonded to the service grounded conductor. So additional SSBJs are superfluous at best, or possibly prohibited parallel pathways.

Cheers, Wayne

 

[david]

2017 NEC 250.80 requires the wireway to be bonded to the service grounded conductor. So additional SSBJs are superfluous at best, or possibly prohibited parallel pathways.

Cheers, Wayne

Yes but that is not prohibiting the bond to go from the neutral in the service disconnect back to metal enclosures.

You do not have to be bonded to the neutral that is passing through a wireway.

The engineer is using a supply side bonding jumper from the service disconnect to bond the wireway.

 

[david]

Keep in mind metal conduit is an approved ssbj nothing says it has to be a wire type ssbj.
The engineer is using a design choice and having a wire type ssbj installed

I see a lot of ct cabinets with removable factory jumpers.
The CT cabinet can be bonded in the same way.

You can use metal conduit ssbj from the service disconnects neutral back to the CT cabinet & the metal wireway. Nothing says they have to be bonded from the grounded conductor passing through. 250.80 only requires the bond.

 

[hhsting]

Making the assumption that the conduits are not pvc.

The engineer is trying not to create a parallel path for the neutral current.

He is having bonding jumpers installed from the service disconnects back to the metal wire way.

The engineer does not want the neutral bonded in the wireway supply side of the service disconnects

How is the CT cabinet bonded?

CT cabinet is existing. Not sure. I just would like to know how to handle it with what NEC 2017 saying. What is the best way to handle this code wise?

 

[david]

CT cabinet is existing. Not sure. I just would like to know how to handle it with what NEC 2017 saying. What is the best way to handle this code wise?

From what you posted the engineer made that choice for you.

As far as the NEC goes there are options

A service is differant than a feeder from a transformer

The neutral from a service can be bonded as many times as you want to on the supply side of the overcurrent protection on a comercial service.

And I say commercial because of the new allowance for the emergency disconnects for dwellings

A bonding jumper can be taken from the neutral in the wireway to make this bond

The ssbj can originate in the service disconnect and make this bond

And the code identifies metal conduit as an approved ssbj