Cost reduction for incoming equipment

[Pdan]

The present design at an industrial facility includes a feeder connected to the secondary of a utility owned 20MVA transformer. The feeder serves a customer owned outdoor 12,470V switchgear lineup with a 1200A main breaker and three branch breakers. The three branch breakers feed three separate 1200A switchgear lineups that are located inside a substation. Each lineup is equipped with a main breaker and branch breakers with a total load of about 300A. The outdoor switchgear allows the second and third lineups in the substation to be installed at a later date with no outages incurred to the ones previously installed.

1. Can the outdoor switchgear be replaced by a sectionalizing cabinet with 600A elbow connectors, or do the secondary feeders from the transformer have to terminate at an OCPD?
2. If a sectionalizing cabinet can be used, are 600A elbows available in loadbreak type? If not available, can they still be connected while energized, but with no load (open main circuit breaker on downstream switchgear)?
3. Another option is to connect the transformer secondary directly to the three substation switchgear main breakers. Would this be allowed, or would connecting three separate feeders to the transformer be a question for the utility company?

Thanks for any insight on this matter.

 

[Pdan]

I re-read the post and #1 should have said, "...or does the secondary feeder from the transformer..."

 

[jim dungar]

What are you trying to accomplish? Are you trying to get rid of all the customer owned MV switchgear?
What do you want the one-line to look like?

 

[Pdan]

I am trying to feed three separate switchgear lineups from a utility owned transformer (one lineup is installed right away and the other two sometime in the future).

In one alternative I get rid of the outdoor switchgear described in the present design above and replace it with a sectionalizing cabinet. Would placing MV junctions and elbow connectors between the transformer secondary and the OCPDs in the switchgear comply with the NEC? Also, if 600A elbows could be connected while energized (but with no load), this would allow the future switchgear to be installed and energized without having to schedule an outage (preferred alternative).

In the second alternative I don’t use any outdoor equipment and use three separate feeders routed from the transformer secondary directly to the OCPDs in the switchgear. Would this arrangement comply with the NEC? Also, is it likely that the utility company would have an issue with this? This alternative would require an outage to install future switchgear, so it is not the preferred method).

 

[jim dungar]

What type of switchgear are you trying to avoid? Have you considered padmount style switches?

 

[petersonra]

The present design at an industrial facility includes a feeder connected to the secondary of a utility owned 20MVA transformer. The feeder serves a customer owned outdoor 12,470V switchgear lineup with a 1200A main breaker and three branch breakers. The three branch breakers feed three separate 1200A switchgear lineups that are located inside a substation. Each lineup is equipped with a main breaker and branch breakers with a total load of about 300A.

So what is the point of having a bunch of 1200 A switchgear with 300 A loads? Just curious.

 

[Pdan]

The total load on the transformer may approach 1000A, the padmount switches are typically 600A.

1200A is common for 15kV switchgear. The facility distribution system is 12,470V and primarily uses loop feeders between different switchgear lineups to serve various loads including buildings and high mast lighting.