Service Disconnect, Whats the Main ?

[gregory]

I have a 1200 ampere 277/480 volt service that has a 1200 ampere main switch ahead of the metering. there are 8 meters with 8-200 ampere disconnects in a meter bank. These disconnects and meters are all located outside. The building contains 8 commercial spaces fed by each 200 ampere feeder. Is the 1200 ampere fused & ground fault protected switch considered to be the service disconnect or are the 200 ampere individual meter & mains considered to be the required service disconnect? If the 1200 ampere main ahead of the meter is considered the required main, can it be the required disconnect for multiple offices? All indoor panels also have a disconnect.
If You look at the 1 line diagram for services Figure 230.1, It shows the required disconnecting means after the Terminal box, meter & or other enclosure, This service is underground. This makes me think that the 1200 fused switch is not the service disconnect because it is ahead of the metering.

 

[pierre]

Re: Service Disconnect, Whats the Main ?

Gregory
The 'first point of disconnect' is your 1200 amp SERVICE disconnect. The 8-200 amp disconnects are not service equipment, they are FEEDER disconnects. The 1200 amp service disconnect is where the Grounded conductor (neutral) and the equipment ground conductor are bonded together.
The 8-200 amp disconnects have the Grounded conductor and the equipment ground conductor separated.

Pierre

 

[hurk27]

Re: Service Disconnect, Whats the Main ?

Pierre
This building has one service drop.
one meter disconect (1200amp) as allowed by 230.82 (2)
and 8 meter sockets with 8 individual service disconects (200amp) that feed's 8 service entrance cable's feeding 8 sub-panel's there is no requirment for the separtion of the ground's and neutral's untill after the 8 service disconect's.
This is also dictated by the manufacture of these multi-meter packs as all the ones I have ever seen have a common ground/neutral buss and can't be seperated. The neutral buss is not isolated from the cabnet.

 

[david]

Re: Service Disconnect, Whats the Main ?

The 8 ea 200 amp meter feeder disconnects can not be service disconnects. The max number of service disconnects group in any one location would be six.

The 1200 amp main would be your service disconnect.

[ July 26, 2003, 02:04 AM: Message edited by: david ]

 

[david]

Re: Service Disconnect, Whats the Main ?

If the (?neutral?) is factory bonded to the enclosure with no way of breaking that bond, I would think these meter disconnects are rated service only disconnects.

If that is true, I could see two good reasons to break up the 8 service disconnects into two groups of four.

1 by breaking them up you would not have to have the main ahead of the group.

Second you would bring the load down on each group and the expensive ground fault protection would not be required to protect the equipment at the service.

[ July 26, 2003, 05:44 AM: Message edited by: david ]

 

[gregory]

Re: Service Disconnect, Whats the Main ?

Pierre, David & Hurk,
I want to thank you all for your replies. They are all good and express different points of view. I am going to go to the job site and see if the 200 amp meter-mains are bonded to the enclosure by the factory as Hurk suggested. At some point either in the 1200 ampere switch or the 200 ampere switches there should be a removable bonding jumper. That should help to indicate what is considered to be the required service disconnect. I would expect the 1200 amp switch to contain the grounding electrode conductor and bonding jumper. I will let you know what I find out.

Again Thanks.
Greg