Bonding the neutral at the device or at the service

[Eddy Current]

I was alway told that you didn't have to bond the neutral at a disconnect if it was bonded at the service? Is this just a rule of thumb? What scenario would cause you to bond a neutral at a disconnect? What would be the purpose of bonding it at a disconnect if its not bonded at the service?

 

[kwired]

I was alway told that you didn't have to bond the neutral at a disconnect if it was bonded at the service? Is this just a rule of thumb? What scenario would cause you to bond a neutral at a disconnect? What would be the purpose of bonding it at a disconnect if its not bonded at the service?

The grounded conductor (neutral) is always bonded to enclosures at or on the supply side of service disconnecting means. Beyond the service disconnecting means you must run separate grounded (neutral) and equipment grounding conductors. Some exceptions such as existing feeders to separate buildings or existing ranges or dryers that were permitted to bond to the grounded conductor at the time the circuit was initially installed.

 

[augie47]

What kwired said.......
added: it's not a "rule of thiumb" , 250.24 is your Code reference. {especially 250.24(A)(5) & (B) }

 

[Eddy Current]

So what would be a scenario where i would have to put that little bonding screw in a disconnect out in the field?

 

[Timebuilder]

So what would be a scenario where i would have to put that little bonding screw in a disconnect out in the field?

That would be in a "service" disconnect. That little screw is a main bonding jumper. Then, you peel off the little label that says "main" and apply it to the device.

The reason you would not use it for other than a service disconnect is to avoid objectionable current. By connecting the neutral and equipment grounding conductors downstream of the main, you create a scenario where current would normally flow in the EGC, and that's a no-no. The EGC is for fault currents ONLY, so any currents other than fault currents are called "objectionable."

 

[don_resqcapt19]

So what would be a scenario where i would have to put that little bonding screw in a disconnect out in the field?

Other than service disconnects, it may also be used at the first OCPD for a separately derived system. The rules for SDS requires bonding at a single point between the source and the first disconnect or within the first disconnect.

 

[Dennis Alwon]

So what would be a scenario where i would have to put that little bonding screw in a disconnect out in the field?

Are you talking a disconnect for a piece of equipment? That is for the equipment grounding conductor not the neutral. Once you past the main service disconnect then the bonding screw is for the equipment grounding conductor.

 

[Eddy Current]

Are you talking a disconnect for a piece of equipment? That is for the equipment grounding conductor not the neutral. Once you past the main service disconnect then the bonding screw is for the equipment grounding conductor.

Yeah sorry no neutral should have been mentioned in this thread. Bonding the green screw to a disconnect is what i have been referring to, i don't know what made me think neutral.