Grouping disconnects

[mpd]

Yes, there it is. Exhibit 230.25 of the 2002 Handbook. It shows a single what appears to be a utility owned transformer with 2 separate laterals. Each lateral feeds a disconnect so 230.72 does not apply since there is only 1 service cable per service lateral/drop.

It is my belief that if they took the same exhibit and only showed 1 laterall coming to a 2 gang meter, the discos would have to be grouped per 230.72.

230.72 simply offers no exception. The service conductors are from the point of service to the disconnect.

230.72 applies to 230.71

 

[don_resqcapt19]

Yes, there it is. Exhibit 230.25 of the 2002 Handbook. It shows a single what appears to be a utility owned transformer with 2 separate laterals. Each lateral feeds a disconnect so 230.72 does not apply since there is only 1 service cable per service lateral/drop.

It is my belief that if they took the same exhibit and only showed 1 laterall coming to a 2 gang meter, the discos would have to be grouped per 230.72.

230.72 simply offers no exception. The service conductors are from the point of service to the disconnect.

First handbook commentary and exhibits are not code...they are only opinion.

The commentary and supplementary materials in this handbook are not a part of the Code and do not constitute Formal Interpretations of the NFPA (which can be obtained only through requests processed by the responsible technical committees in accordance with the published procedures of the NFPA). The commentary and supplementary materials, therefore, solely reflect the personal opinions of the editor or other contributors and do not necessarily represent the official position of the NFPA or its technical committees.

Second there is no need for an exception in 230.72. 230.71 permits multiple sets of six disconnects, 230.72 only requires that the disconnects of any one set be grouped with the others of that set.

 

[jim k]

As it's written, there are two ways to interpret 230.40, Exception 1. I suspect that don_resqcapt19 & ivsenroute are each interpreting it differently. The difference depends on whether the clause "run to each occupancy" modifies "service-entrance conductors" or "service." The sentence isn't clear. Here it is (parenthetical phrases omitted for clarity):

A building . . . shall be permitted to have one set of service-entrance conductors for each service, . . . run to each occupancy or group of occupancies.

If "run to each occupancy" modifies "service entrance conductors," it says that you can have multiple SECs (one set per occupancy) for each service. I think that this is don_resqcapt19's interpretation.

Alternatively, if "run to each occupancy" modifies "service," it says that you?re only permitted to have one set of SECs run to each occupancy . . . for each service to the building. I think that this is ivsenroute's interpretation.

Since it's an *exception* to the general rule stated before it, I think that there's little doubt that the authors intended it to mean that, under specified conditions, you could have multiple SECs branched off of a single drop or lateral. But that's not quite what it really says.

- Jim Katen, Oregon