Treating a building feeder on a college campus like a utility service feeder

[mshields]

Normally, on a college campus, I treat the "feeder" to the building from the pad mounted transformer like any other feeder from a transformer; i.e. 3 phase, neutral and SSBJ.

The state inspector who oversees this particular school recently informed me that as per 225.36, you could essentially treat this feeder the same way you would treat the service conductors comming in from a utility pad mount. I.e. 3 phase and instead of a Grounded Service Conductor, just a "grounded conductor".

So you bond at the main disconnect and the main disconnect needs to be UL listed for service entrance.

My question is this, whether it's a service or a feeder to a primary metered campus building, what color coding should the Grounded Conductor and Grounded Service Conductor be. Green? White? Gray" or none of the above.

 

[Smart $]

If it is under the NEC, there's 2-1/2 pages about 'em towards the front, otherwise known as Article 200.

In a few words, white or gray insulation, or three stripes on insulation of either color, a ridge, or distinctive [white or gray] marking at the terminations at the time of installation.

Definitely not green. :happysad:

 

[david luchini]

Normally, on a college campus, I treat the "feeder" to the building from the pad mounted transformer like any other feeder from a transformer; i.e. 3 phase, neutral and SSBJ.

The state inspector who oversees this particular school recently informed me that as per 225.36, you could essentially treat this feeder the same way you would treat the service conductors comming in from a utility pad mount. I.e. 3 phase and instead of a Grounded Service Conductor, just a "grounded conductor".

An SBJ would need to be installed at both ends, if it does not create a parallel path for the grounded conductor, in order to not have the SSBJ.

 

[mshields]

SSBJ on both ends

SSBJ on both ends

Thank you gentlemen

David - When you say a SSBJ would need to be provided on both ends (where not provided as a 5th conductor between the transformer and main disconnect, but exactly what conductor are we talking about here?

Lets take the facilities main disconnect "end". Clearly you need a Ground to Neutral connection at this equipment. But I would call that, a "system bonding jumper" not an SSBJ. Or are the two synonymous. I know they are both sized per 250.102.


Much appreciated,

Mike

 

[augie47]

If the system is not a POCO service but is fed from the campus grid then it would fall under 250.30 not At 300. This install was handles a bit differently depending on the applicable Code cycles* but 250,30(A)(1) often applies as without a metallic conduit system, a parallel path is not normally present if you install a system bonding jumper at the source (transformer) and the first disconnecting means.
250.30(A)(2) eliminates the need for a supply side bonding jumper in those situations.

*I think in the '08 Code they failed to list the 250.30(A)(2) exception.

 

[Smart $]

Thank you gentlemen

David - When you say a SSBJ would need to be provided on both ends (where not provided as a 5th conductor between the transformer and main disconnect, but exactly what conductor are we talking about here?

Lets take the facilities main disconnect "end". Clearly you need a Ground to Neutral connection at this equipment. But I would call that, a "system bonding jumper" not an SSBJ. Or are the two synonymous. I know they are both sized per 250.102.


Much appreciated,

Mike

Not an SSBJ... an SBJ, system bonding jumper. One 'S'.

Where an SSBJ, supply-side bonding jumper (think EGC before OCPD), is installed, you can only install an SBJ at one end or the other. If no metallic paths exist between source equipment and disconnecting means equipment, i.e. their noncurrent-carrying metal parts, you can forego installing the SSBJ and install an SBJ at both ends.