New 230.82(3)

[xformer]

How does a disconnect switch disconnect a meter without disconnecting the service...?

 

[david luchini]

How does a disconnect switch disconnect a meter without disconnecting the service...?

It doesn't...230.82(3) permits a disconnecting means for use by the utility for work on their meter. It will disconnect the service, but it won't have any overcurrent protection. The overcurrent protection will be located at or adjacent to the service disconnecting means.

 

[augie47]

Sometimes it gets to be an interesting proposition.
As david points out, the purpose of the switch is for utility use to disconnect the meter for servicing. In this areas they are normally locked "on" and "closed" and often have no overcurrent protection and are not considered "Service Disconnects".
The "hairy" part comes into play when the SCA exceeds 10k as most no fuse switches are ratted 10K max AIC.
If the utility then uses fusible disconnects to meet the AIC requirement, the fuses are not accessible to the owner when under POCO lock.

 

[don_resqcapt19]

It doesn't...230.82(3) permits a disconnecting means for use by the utility for work on their meter. It will disconnect the service, but it won't have any overcurrent protection. The overcurrent protection will be located at or adjacent to the service disconnecting means.

I don't know why, but our utility requires that the meter disconnect device have overcurrent protection.

B. Self?Contained Meters
1. Single, and three phase, 480V, less than 201 Amp, services
a) A breaker or fused disconnect located on the line side of the meter (cold sequence metering) is required for all 277/480V and 480V services 200 amp and below.
b) It shall be the customer?s responsibility to provide the proper interrupting rating device on the line side.
c) Ameren should be contacted to determine available short circuit current.
d) Use of separate enclosures for the line side protective device and the meter enclosure is acceptable. However they must be mounted directly above, or on a horizontal plane, within 4 feet of one another.
e) Continuous conduit with no LB?s or any other connector that could allow access to un?metered wiring is allowed between the protective device enclosure and meter enclosure.
f) Sealing provisions for the line side protective device must be provided to prevent access to un?metered conductors within this enclosure.
g) A pad lockable door for access by the customer to operate the protective device should be provided.

 

[Smart $]

I don't know why, but our utility requires that the meter disconnect device have overcurrent protection.

Nothing prohibits the meter disconnect from having OCP.

Aside from that, the thread title is "New 230.82(3)"...

While 230.82(3) has been modified through the last few cycles, it is far from new. The 2014 edition added the following:

A meter disconnect shall be legibly field marked on its exterior in a manner suitable for the environment as follows:

METER DISCONNECT
NOT SERVICE EQUIPMENT​

 

[fmtjfw]

We had a discussion of this recently and a manufacturer's rep said they don't rate unfused disconnects higher than 10kAI, but that they could have withstand and closing ratings higher (like fused disconnects).

The minimum withstand rating of a UL414 meter socket is 10kA rms, no short circuit testing required.
Any socket rated above 10kA must be tested for 30kA peak current.

[The meter may blow up while the socket "survives".]

90.2 Scope.
(B) Not Covered. This Code does not cover the following:
...
(5) Installations under the exclusive control of an electric utility where such installations
a. Consist of service drops or service laterals, and associated metering, or
...

That does not call out meter disconnects. But:

230.82 Equipment Connected to the Supply Side of Service Disconnect. Only the following equipment shall be permitted to be connected to the supply side of the service disconnecting means:
....
(3) Meter disconnect switches nominally rated not in excess of 1000 V that have a short-circuit current rating equal to or greater than the available short-circuit current, provided that all metal housings and service enclosures are grounded in accordance with Part VII and bonded in accordance with Part V of Article 250. A meter disconnect switch shall be capable of interrupting the load served.
....

230.94 Relative Location of Overcurrent Device and Other Service Equipment. The overcurrent device shall
protect all circuits and devices.

Exception No. 1: The service switch shall be permitted on the supply side.

"Service Switch" is not defined.

Our POCO requires a meter disconnect switch for 480V self-contained metering:

"All metering shall be installed on the line side of the Customer?s main disconnecting means except for a 480Y/277 volt metering installation where the Company requires a meter disconnect ahead of the meter or where the NEC requires a main disconnect ahead of a group of more than six (6) meters. See Figures 42, 43 and 45 for self-contained, 480Y/277 volt, 4-wire metering installations. Consult Company prior to purchasing or installing equipment."

Figure 42 states: "CUSTOMER SHALL FURNISH AND INSTALL METER DISCONNECT SWITCH (UNFUSED)."

 

[texie]

I might add to this discussion that Milbank has a combo meter main that also has a meter disconnect as well as a service disconnect that makes this type of installation neater and easier for complying with POCO cold sequence requirements.