​Here is a summary of the range of ANSI C12 Standards that NEMA Members work to develop and maintain.

Meter Socket Jaw Rejection Clip and Meter Reduced Blade

As customer loads have increased through the years, higher-rated equipment has become necessary. What was once adequate at 100 amps now requires 200 amps. Now, the need for higher-rated equipment is common; thus, 320-amp meter sockets and Class 320 amp meters are being installed.  There is a unique feature that was introduced in the 320-amp equipment: the anti-inversion clip in the meter socket in combination with the reduced blade (“D” terminal) on the meter. The purpose of this paper is to educate the utility metering industry about these components, their function, and their limitations.

• Please see our White Paper on the subject for more information.

Meter Socket Adapters

In light of industry trends such as the integration of distributed solar photovoltaic generation and the installation of backup generators in disaster-prone areas, meter socket adapters are being more commonly used within the service entrance of residential, commercial, and industrial buildings. The purpose of this paper is to educate owners and installers of meter socket adapters on general use applications for these products, as well as design and testing requirements.

• Please see our White Paper on the subject for more information.

Evaluating Meter Socket Lifespan

Under ideal conditions, meter socket manufacturers anticipate that meter sockets will have a lifespan of approximately 20-25 years. Because less-than-ideal conditions often surround meter socket installation and operation, NEMA’s Meter Mounting and Test Equipment Section Members recommend that utilities manually inspect sockets as regularly as is economically and operationally practicable.

There is a range of commonly occurring factors which are likely to reduce socket lifespan. During inspections, utility workers should look for evidence of these factors in the form of discolored (i.e., blue) or darkened connections resulting from over-heating and/or micro-arcing; loose, mismatched or out-of-place electrical connections; or rust on any of the metal components due to corrosion.

• Please see our White Paper on the subject for more information.