Supply Side Bonding Jumper (SSBJ)

[charlie b]

I am having a disagreement with an engineer whose design I am reviewing. It boils down to this: (1) What exactly is an SSBJ, (2) What exactly does it do for a living, and (3) Can you accomplish what it does for a living by having metal conduit from service transformer to the main service panel and by bonding that conduit to enclosures at both ends using a “wire” that is just a few inches long and is sized per 250.102(C)? He says yes. I had understood (perhaps incorrectly) that the SSBJ was to be run inside the conduit along with all the other conductors.

Part of his argument came from the 2011 Handbook. Here is his statement: “The 2011 NEC Handbook provides an application example specifically describing bonding multiple raceways---not running an addition conductor in the raceway(s).” My only copy of the Handbook is at my office, and I am not permitted to go there while the virus is doing its thing. I suspect he might be taking what the handbook says out of context.

Can someone explain the situation to me? Can someone post (without violating copyrights) that portion of the Handbook?

 

[augie47]

(1) "Bonding Jumper, Supply-Side. A conductor installed on the supply side of a service or within a service equipment enclo‐ sure(s), or for a separately derived system, that ensures the required electrical conductivity between metal parts required to be electrically connected. "
(2)It ensures the required electrical conductivity between metal parts required to be electrically connected. In the case of a SDS install, continuit and ground fault return path between the transformer and the secondary disconnecting means.
(3). Yes, Any 250.118 effective ground path
No Handook handy, sorry

 

[jaggedben]

250.30(A)(2) (in part)

... The supply-side bonding jumper shall be permitted to be of nonflexible metal raceway type or of the wire or bus type as follows: ...

 

[charlie b]

Thanks. I told the other engineer that I conceded his point.

 

[don_resqcapt19]

A metallic service raceway is bonded by a supply side bonding jumper, but that bonding is only required at one end of the service raceway. There is never supply side bonding jumper of the wire type run in a raceway on the line side of the service disconnet.

 

[electrofelon]

There is never supply side bonding jumper of the wire type run in a raceway on the line side of the service disconnect.

Don, I disagree. I did just this a month ago to bond a CT cabinet.

 

[kwired]

Don, I disagree. I did just this a month ago to bond a CT cabinet.

But shouldn't that cabinet be bonded to the grounded conductor regardless? Therefore no reason to need a separate SSBJ run through the raceway.

 

[texie]

Don, I disagree. I did just this a month ago to bond a CT cabinet.

I was going to use the same example.

 

[texie]

But shouldn't that cabinet be bonded to the grounded conductor regardless? Therefore no reason to need a separate SSBJ run through the raceway.

Can be done either way.

 

[kwired]

Can be done either way.

One end bonds to the cabinet and the other end lands where?

 

[texie]

One end bonds to the cabinet and the other end lands where?

At the service disco. Often done when you have PVC between the CT cabinet and the disco.

 

[kwired]

At the service disco. Often done when you have PVC between the CT cabinet and the disco.

And why not either have grounded conductor terminal that is bolted to the cabinet or if using insulated terminal enough ports to include a bonding jumper to land on the cabinet?

 

[texie]

And why not either have grounded conductor terminal that is bolted to the cabinet or if using insulated terminal enough ports to include a bonding jumper to land on the cabinet?

That works, too.

 

[electrofelon]

And why not either have grounded conductor terminal that is bolted to the cabinet or if using insulated terminal enough ports to include a bonding jumper to land on the cabinet?

In this case there was a POCO requirement that didnt allow connecting the neutral (directly) to the C T cabinet (I dont know why, Im just the messenger). What it is interesting is the code doesnt specifically say how to run a SSBJ on services with multiple enclosures. It seems logical to run a tap to each enclosure like we do for GEC taps, but again it isnt stated.

 

[electrofelon]

Also A single SSBJ run with the service conductors back to the disco is often easier than tapping a big cob of neutrals in say a pull box

 

[kwired]

In this case there was a POCO requirement that didnt allow connecting the neutral (directly) to the C T cabinet (I dont know why, Im just the messenger). What it is interesting is the code doesnt specifically say how to run a SSBJ on services with multiple enclosures. It seems logical to run a tap to each enclosure like we do for GEC taps, but again it isnt stated.

Around here that CT cabinet is generally considered on supply side of service point and not covered by NEC anyway, POCO can do what they want with it. Every one I have encountered usually has multiport terminal bars though not the "Polaris" type with insulation but rather bare terminal and an insulating cover. They usually don't insulate the grounded conductor terminal but do add a bonding jumper to the enclosure and usually they install a ground rod as well

 

[don_resqcapt19]

Don, I disagree. I did just this a month ago to bond a CT cabinet.

Yes, you are correct. Not done around here because service raceways other then those underground are required to be rigid conduit. I keep forgetting that other areas don't have that requirement.

 

[kwired]

Yes, you are correct. Not done around here because service raceways other then those underground are required to be rigid conduit. I keep forgetting that other areas don't have that requirement.

But those metal service raceways still need something other than standard locknut to bond them. If you use a wire bonding jumper you are usually landing it in a lug on a bonding bushing and not pulling it through the raceway to another enclosure.