Service Entrance Conductors

[mrmax1200]

I have a building in Hoboken, NJ.
5 stories over parking.
Total units 55
Plans call for a 2000 A underground service from pad mount XFMR, supplied by utility.
55- 208/120 V single phase unit meters.

The original plan called for a 2000 A main switch/Breaker to follow with stack metering accordingly.

The 2000 A switch was impossable to install, because of the hieght needed to comply with the 100 year flood plane ( Elevation 10) which is 3'6" AFF.
This would bring the main switch off the floor into the unit above.

We opted to comply with the code, and install 5 - 400 amp 3 phase fusable disconnects place in our dedicated electrical room area. (see attach)

We came from the pad mount xfmer which is outside the building, and ran 5 -4" PVC Conduits underground to a 12" trough,which is mounted @ 2' AFF to bottom of trough and runs around the room as a wireway for our service conductors, and placed the mains accordingly, around the room.

The utility company has no problem with the conductors in the trough, as long as there is no tapps or splices, and they can seal the trough with seals or barrel locks.

However, the local electrical inspector says that the trough can not be used - #1 Because it is below the flood plane, and the conductors are not fused in the trough.

In my opinion I don't think this is correct, because the plans state any sevice swith,mainbreaker,Panel, or meter must be above flood plane.
It doesn't state wireways or conduit.

Will point of service in the NEC play a part in this debate ?

Is there to much unfused wiring in room (trough) ?

Should I remove the trough and install the wiring in PVC and encase it in concrete ?

- GMS Electric

 

[fc]

Re: Service Entrance Conductors

Just wondered if he said anything about the main disconnects not being group together?

 

[russ]

Re: Service Entrance Conductors

Don't know much about flood planes.

I do think that the meters being in the same electrical room could be considered grouped.

The length of the un-fused service conductors seams to be excessive. I don't think your drawing complies with 230.70(A)(1).

[ August 06, 2004, 06:14 PM: Message edited by: russ ]

 

[necbuff]

Re: Service Entrance Conductors

I am not a flood plane expert either. Depending on the room size I don't beleive the disconnects are grouped. It also appears there is too much unfused conductors in the building although this is usually determined on a case by case by the AHJ unless the locality has amendments for specific distances. As far as the service conductors in the trough, I don't see a problem BUT you would have to bond the trough to 250.66 and any metallic raceways with bonding bushings, hubs or bonding locknuts depending on your knockouts. I would say there could be an argument as to whether water is LIKLEY to enter the enclosure as you would subject to physical damage. What is the likelyhood water will enter the trough ??? If that is the ONLY problem he sees, ask him about w watertight enclosure.

 

[a.wayne3@verizon.net]

Re: Service Entrance Conductors

We get involved in flood plains here in Florida.True my experince has been mostly residential here,As I see it as long as the conduit/trough/raceway is as stated water tight and the disc`s are above flood level not a problem but the spacing between them is a big one.Grouping is what it says grouped together.To have them spread throughout a mechanical room like shown no way IMHO.

 

[russ]

Re: Service Entrance Conductors

If the paralleled conductors never join together on the building side, is it a 2000 amp service, or 5 400 amp services.

 

[russ]

Re: Service Entrance Conductors

I can't see any exception in 230.40 that allows this combination of separate 400 amp services for the 55 units.

 

[iwire]

Re: Service Entrance Conductors

I would call it one 2000 amp service that has 5 disconnects as allowed by 230.71(A).

230.2 Number of Services.
A building or other structure served shall be supplied by only one service unless permitted in 230.2(A) through (D). For the purpose of 230.40, Exception No. 2 only, underground sets of conductors, 1/0 AWG and larger, running to the same location and connected together at their supply end but not connected together at their load end shall be considered to be supplying one service.

230.40 Exception No. 2: Where two to six service disconnecting means in separate enclosures are grouped at one location and supply separate loads from one service drop or lateral, one set of service-entrance conductors shall be permitted to supply each or several such service equipment enclosures.

As far as the original question it is strictly up to the AHJ to decide what constitutes "nearest the point of entrance of the service conductors."

It seems in many areas you must immediately enter the Service Disconnect.

The same with "grouped" disconnects, it is up to the AHJ to determine how close together the disconnects must be to be considered grouped.

Check out this service IMO this is overkill but the NEC leaves it in the hands of the local AHJ to determine what is nearest the point of entrance, by encasing in cement the point of entrance was moved closer to the service disconnect. 230.6