Art. 230.71 in 2020 Nec

[Dennis Alwon]

Is this meter/combo compliant in the 2020 Nec. It, IMO, meets the intent since the busbar can be de-energized but the code seems to not allow it.

230.71(B) Two to Six Service Disconnecting Means.

Two to six service disconnects shall be permitted for each service permitted by 230.2 or for each set of service-entrance conductors permitted by 230.40, Exception No. 1, 3, 4, or 5. The two to six service disconnecting means shall be permitted to consist of a combination of any of the following:

• (1)
  Separate enclosures with a main service disconnecting means in each enclosure
• (2)
  Panelboards with a main service disconnecting means in each panelboard enclosure
• (3)
  Switchboard(s) where there is only one service disconnect in each separate vertical section where there are barriers separating each vertical section
• (4)
  Service disconnects in switchgear or metering centers where each disconnect is located in a separate compartment

Informational Note No. 1:
Metering centers are addressed in UL 67, Standard for Panelboards.
Informational Note No. 2:
Examples of separate enclosures with a main service disconnecting means in each enclosure include but are not limited to motor control centers, fused disconnects, circuit breaker enclosures, and transfer switches that are suitable for use as service equipment.

 

[don_resqcapt19]

The service disconnects themselves must be in separate compartments, and that one is not complaint with the 2020 code. The intent is that the disconnects themselves must be in separate compartments. The busbar on the load side of the first breaker does not enter into this as that is on the load side of the service disconnect. It is the two service disconnects that are the issue, not the load side bus bar.

 

[Dennis Alwon]

The service disconnects themselves must be in separate compartments, and that one is not complaint with the 2020 code. The intent is that the disconnects themselves must be in separate compartments. The busbar on the load side of the first breaker does not enter into this as that is on the load side of the service disconnect. It is the two service disconnects that are the issue, not the load side bus bar.

Yes, I get that but I thought the issue was to make it safe. With caps on the lugs and the 2 breakers in the same enclosure it would appear to be safe but not meet code as written. I am wondering if this was just missed or not.

 

[don_resqcapt19]

Yes, I get that but I thought the issue was to make it safe. With caps on the lugs and the 2 breakers in the same enclosure it would appear to be safe but not meet code as written. I am wondering if this was just missed or not.

It was not missed...the rule is to reduce the possibility of arc flash injuries, not just the shock hazard. Any time you are in an enclosure that contains service conductors there is an increased risk of an arc flash incident even where the conductive surfaces are covered. By having only one service disconnect in an enclosure or compartment, the arc flash risk is reduced.

This was discussed in the UL 67 STP and those panel members could not reach a agreement on the idea that just covering all conductive parts with insulation would provide the required level of safety that the code is looking for.