UL Standard for Safety Meter Sockets
|Publication Date:||5 January 2016|
These requirements cover meter sockets for use with:
a) Watthour and similar meters;
b) Test switches;
c) Metering transformer cabinets; and
d) Metering transformer cabinet interiors
for installation in accordance with the National Electrical Code, NFPA 70.
Meter sockets are marked with a continuous duty ampere rating and may in addition have a maximum use (intermittent) ampere rating of 125 percent or less of the continuous duty ampere rating.
A meter socket, as covered by these requirements, is an assembly of wiring terminals and jaw type contacts for one or more plug-in watthour meters in an enclosure having provisions for securing the meter to the socket.
Some meter sockets may be housed in a metal pedestal enclosure intended for mounting on a concrete slab or in a metal post enclosure intended to be sunk in the ground with or without concrete poured around the post at ground level and either self-supported or intended for separate support. Such posts or pedestals are not intended to serve as the sole support of masts for overhead wiring.
Some meter sockets may be intended for mounting on a mounting post or pedestal for distribution equipment.
Except as indicated in 1.10, as covered by these requirements, a meter socket does not include:
a) A meter,
b) An overcurrent device,
c) An instrument transformer,
d) An arcing or switching part, or
e) A similar component.
A meter socket does not have provision for installation of instrument transformers within the meter socket enclosure.
These requirements cover meter sockets rated:
a) 300 volts alternating current or less, or 600 volts alternating current and
b) 400 amperes maximum per meter position.
These requirements cover metering transformer cabinets and metering transformer cabinet interiors rated maximum 6000 amperes at maximum 600 volts.
As covered by these requirements, a metering transformer cabinet or metering transformer cabinet interior does not include the current transformers.
This Standard contains requirements in Supplement SA that cover meter socket adapters, including adapters with provisions for connection of alternative energy sources, that may contain overcurrent protection.