Note: Descriptions are shown in the official language in which they were submitted.
CA 02411670 2002-11-13
LUG FOR PROVIDING BOTH ELECTRICAL AND MECHANICAL
CONNECTION BETWEEN BUSES AND WATT HOUR METER SOCKETS
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to meter centers for electrical power
distribution
systems. Specifically, it relates to improvements to the meter socket assembly
to
include a lug for providing electrical and mechanical connection between the
buses
and meter socket.
Background Information
In the electric utility industry, plug-in, socket-type watt-hour meters are
commonly used to measure electric power consumption at residential or
commercial
sites. A socket housing, known as a meter center, is typically mounted between
the
electrical power supply and the load. Meter centers may include one or more
meter
compartments, each of which contains a pair of line and load terminals, which
are
respectively connected to electric line and load conductors.
Each meter compartment has a meter socket to which a load and a supply bus
are connected. The load bus connects the meter compartment to the location
wherein
the power is utilized. The supply bus extends from the feeder bus, which in
turn
extends from the utility power lines. The meter socket secures the meter,
providing an
electrical connection between the supply buses and the load buses. This
electrical
connection is formed by single-ended, fastenerless plug-in jaws on the meter
socket,
dimensioned and configured to engage corresponding stabs on the meter.
Currently available watt-hour meter sockets contain many bus connecting and
supporting components, which complicate the assembly process and are
susceptible to
damage or failure under normal operation loads.
Accordingly, an improved meter socket assembly that eliminates unnecessary
components and provides a more durable and reliable meter socket assembly, is
desired.
CA 02411670 2002-11-13
SUMMARY OF THE INVENTION
The present invention is directed to a lug for use within a meter socket
assembly. Four lugs are connected to the meter socket base, one to each
fastenerless
meter jaw. Each lug derives mechanical support from the meter socket plate and
is an
electrical conductor, connecting to one jaw on the meter socket and the
corresponding
wire.
A typical socket for an electrical meter includes two supply buses, and two
load buses, although the present invention is not limited to this number of
corresponding supply and load buses. An electrical connection follows the path
from
the utility lines, through the feeder bus, the supply bus, the meter, the load
bus and
finally to the consumer. The electrical connection from the supply bus,
through the
meter, and to the load bus is formed by double-sided fastenerless plug-in jaws
on the
meter socket, with each plug-in jaw corresponding to one bus, and a stab on
the meter
corresponding to each jaw. To connect each bus to the corresponding plug-in
jaw in
the situation wherein a round wire instead of a flat busbar is utilized, prior
art required
separate bus connectors within an electrically insulative molded support to
hold the
bus and meter socket assembly together while providing the necessary
electrical
connection.
The present lug invention is constructed of an electrically conductive
material
such as aluminum and includes a vertical stab which engages with the
fastenerless
jaws located on the under side of the meter socket. A fastener, such as a self
threading screw, keeps the lug engaged with the socket. The conductive lug
also
includes a wire opening with a clamping means. This wire opening slides over
and
engages with one of the supply or wires. The wire opening clamping means, such
as a
setscrew, is tightened around the wire, securing the connection. Once
connected, the
electrically conductive lug provides the necessary current path to the meter,
without
the use of additional bussing andlor supports. Furthermore, the fastener
coupling the
lug to the meter socket provides sufficient support to eliminate the
previously required
molded insulative supports, necessary to support the supply wires and meter
socket
assembly.
It is therefore an aspect of the present invention to provide a watt-hour
meter
with integral line and load buses.
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CA 02411670 2002-11-13
It is another aspect of the present invention to provide mechanical support
for
the wires within a meter socket assembly and to provide an electrical path
between the
wire and the plug-in jaw on the meter socket, while minimizing the number of
components necessary.
It is a further aspect of the present invention to decrease the construction
cost
and complexity of a meter socket assembly while increasing its durability, by
minimizing the number of necessary components.
These and other aspects of the invention will become apparent through the
following description and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is an isometric view of a meter for which the present invention will
be used.
Figure 2 is a front view of a meter socket for a watt-hour meter, illustrating
the
location of the present lug invention.
Figure 3 is a front view of a meter socket for a watt hour meter, and the
circuit
breaker panel associated with the meter, illustrating the location of the
present lug
invention.
Figure 4 is a top view of the Iug of the present invention.
Figure 5 is a front view of a lug according to the present invention.
Figure 6 is an exploded view, illustrating the assembly of the invention to
the
meter socket using an insulative fastener.
Figure 7 is a bottom view of the assembly according to the present invention.
DETAILED DESCRIPTION
The present invention is directed to an improved meter socket plate supported
lug for providing mechanical support and electrical connection for wires
leading to
electrical meter sockets.
A typical electrical meter with which the present invention will be used is
illustrated in Figures 1-3. The meter cabinet 10 includes a meter socket 12,
for
electrical connection with a meter 14. The meter socket 12 includes a socket
plate 16,
having a plurality of double-ended fastenerless meter jaws 18, dimensioned and
configured to receive corresponding prongs on the back face of the meter 14
(not
shown, and well known). The meter cabinet 10 also includes a pair of supply
wires
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CA 02411670 2002-11-13
20, and a pair of load wires 22, which in this case lead from the metered
socket 12 to
the circuit breaker panel 24, protecting the ultimate load for the current.
The path of
the current is therefore from the supply wires 20, through the first set of
double-ended
fastenerless meter jaws 18, through the meter 14, through the second pair of
double-
s ended fastenerless meter jaws 18, to the load wires 22, through the circuit
breaker 24,
and ultimately to the load.
The double-ended fastenerless meter jaws 18 include substantially identical,
electrically connected spring-biased jaws on the front and back surfaces of
the socket
plate 16. These jaws are dimensioned and configured to secure a flat surface
between
them, for example, the prongs on the rear surface of the meter 14, or the
angled
busbars commonly used within some meter centers. However, in this application,
the
supply wires 20 and load wires 22 are round wires. The present invention is
directed
towards forming the electrical and mechanical connection between the wires 20,
22,
and the double-ended fastenerless meter jaws 18. The present invention
replaces a
prior art apparatus wherein the buses were partially encased in and supported
by
electrically insulative molded supports, and a separate electrically
conductive lug was
used to connect the wires 20, 22 to the meter jaws 18.
The lug 100 of the present invention, shown in Figure 3, accomplishes both;
mechanical support and electrical connectivity for the wires 20, 22. The lug
100 is
electrically conductive, being constructed of aluminum in the preferred
embodiment.
However, it will be appreciate by the skilled artisan that any number of
electrically
conductive materials could be used.
As shown in Figure 4, the lug 100, in the preferred embodiment, has a vertical
stab 110. This vertical stab 110 engages with the double-edged fastenerless
jaw 18
corresponding to the meter 12 supply stab engaged to the other end of the jaw
18 on
the opposite side of the socket assembly 12. The lug 100 also has a pilot hole
120 for
threading of fastener 130 to further secure the lug 100 to the meter socket
12. To
provide the electrical connection with the supply bus, the lug 100 has an
engaging
wire opening 140 with a fastening means 150. The supply wire (not shown)
passes
through the wire opening 140 and is fastened in place using the fastening
means. The
edge 162 fits against surface 164 to prevent rotation of the lug.
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CA 02411670 2002-11-13
In the preferred embodiment, the lug 100 is aluminum. As illustrated in
Figure 5, the fastener 130 is a screw passing through hole 160 in the meter
socket and
hole 120 and threading into the lug. The fastening means 150 on the engaging
loop
140 is a setscrew. However, it will be appreciated by those skilled in the art
that any
number of commonly used fasteners could be used as alternatives to those
utilized in
the preferred embodiment.
Figure 6 shows an exploded view of the preferred lug 100, fastener 130 and
meter socket 12 having double-edged fastenerless meter jaws 121. Figures 2 and
7
show front and bottom views, respectively, of the completed assembly of the
preferred embodiment. Figure 2 illustrates that the instant lug 100 can be
used at bath
the supply and tenant engagement locations.
By providing one component that serves the functions of multiple prior art
components, including support and electrical connectivity, the lug 100 of the
instant
invention greatly simplifies the construction of the meter socket assembly 12.
Additionally, because the number of components is reduced, damage and/or
failure
leading to meter socket assembly 12 failure is minimized.
While a specific embodiment of the invention has been described in detail, it
will be appreciated by those skilled in the art that various modifications and
alternatives to those details could be developed in light of the overall
teachings of the
disclosure. Accordingly, the particular arrangements disclosed are meant to be
illustrative only and not limiting as to the scope of the invention which is
to be given
the full breadth of the appended claims and any and all equivalents thereof.
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