U.S. patent application number 14/941411 was filed with the patent office on 2016-11-03 for meter socket adaptor.
The applicant listed for this patent is SolarCity Corporation. Invention is credited to Garret Bautista, Cormac McHugh.
Application Number | 20160320427 14/941411 |
Document ID | / |
Family ID | 57204771 |
Filed Date | 2016-11-03 |
United States Patent
Application |
20160320427 |
Kind Code |
A1 |
Bautista; Garret ; et
al. |
November 3, 2016 |
METER SOCKET ADAPTOR
Abstract
This disclosure pertains to methods and apparatus for
interfacing an onsite power generation system with an existing main
electric panel. The interfacing is performed by: attaching a fifth
jaw connector to a neutral bridge within an existing meter socket;
wiring AC supply lines from the onsite power generation system to
load side jaws of a five blade meter socket adapter; and wiring a
neutral line from the onsite power generation system to a fifth
terminal of the meter socket adapter. The lines from the onsite
power generation system are routed through an opening formed in the
meter socket adapter. The meter socket adapter is then inserted
into the meter socket so that five jaws in the socket receive all
five blades of the meter socket adapter. The blades of the meter
are then plugged into the jaws on the opposite end of the meter
socket adapter.
Inventors: |
Bautista; Garret; (San
Rafael, CA) ; McHugh; Cormac; (San Rafael,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SolarCity Corporation |
San Mateo |
CA |
US |
|
|
Family ID: |
57204771 |
Appl. No.: |
14/941411 |
Filed: |
November 13, 2015 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
62155291 |
Apr 30, 2015 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01R 1/0416 20130101;
H01R 27/02 20130101; H01R 33/94 20130101; H01R 31/06 20130101 |
International
Class: |
G01R 1/04 20060101
G01R001/04; H01R 31/06 20060101 H01R031/06 |
Claims
1. A meter socket adapter for interfacing an onsite power
generation system with an electrical service panel, the meter
socket adapter comprising: a cylindrical body having a first end
and a second end; an opening defined by a lateral wall of the
cylindrical body; a set of four blade connectors on the first end
of the cylindrical body positioned to connect to four jaw
connectors in a meter socket of the electrical service panel,
wherein two of the blade connectors are electrically coupled to
supply terminals for wiring two respective AC supply lines from the
onsite power generation system entering the meter socket adapter by
way of the opening; a corresponding set of four jaw connectors on
the second end of the cylindrical body, electrically coupled to the
respective four blade connectors on the first end, positioned to
mate with four additional blade connectors of a utility meter; a
neutral terminal for attaching a neutral wire from the onsite power
generation system; and a fifth blade connector electrically coupled
to the neutral terminal and disposed on the first end of the
cylindrical body for electrically coupling the neutral wire of the
onsite power generation system to a neutral jaw connector in the
meter socket at the same time that the four blade connectors mate
with the four jaw connectors in the meter socket.
2. The meter socket adapter of claim 1, wherein the onsite power
generation system comprises a photovoltaic array.
3. The meter socket adapter of claim 1, wherein the two AC supply
lines comprise AC phase 1 and AC phase 2 respectively.
4. The meter socket adapter of claim 1, wherein the four blade
connectors of the meter socket adapter are arranged in a symmetric
configuration.
5. The meter socket adapter of claim 4, wherein the fifth blade
connector is arranged orthogonally with respect to the set of four
blade connectors.
6. The meter socket adapter of claim 1, wherein the cylindrical
body defines multiple openings configured to accommodate the fifth
blade connector.
7. The meter socket adapter of claim 1, wherein the first end of
the cylindrical body has a size and shape in accordance with the
standard meter socket.
8. A method of interfacing an onsite power generation system to an
existing electrical service panel via a meter socket adapter, the
method comprising: removing a utility meter from a meter socket of
the existing electrical service panel to expose a meter socket;
electrically coupling a fifth jaw connector to a neutral wire
terminal inside the meter socket; connecting at least two AC power
supply lines from an onsite power generation system to respective
first and second load side terminals of the meter socket adapter by
way of an opening in a side wall of the meter socket adapter;
connecting a neutral wire from the onsite power generation system
to a neutral terminal in the meter socket adapter via the opening
in the side wall of the meter socket adapter, wherein the neutral
terminal is electrically connected to a neutral blade connector of
the meter socket adapter; plugging a first side of the meter socket
adapter into the meter socket so that first and second supply side
blade connectors of the meter socket adapter are connected to
respective first and second supply side jaw connectors of the meter
socket, and first and second load side blade connectors of the
meter socket adapter are connected to respective first and second
load side jaw connectors of the meter socket, and the neutral blade
connector is connected to the fifth jaw connector; and connecting
the utility meter to an opening in a second side of the meter
socket adapter.
9. The method of claim 8, wherein the onsite power generation
system comprises a photovoltaic array.
10. The method of claim 8, wherein the at least two AC supply lines
comprise AC phase 1 and AC phase 2 respectively.
11. The method of claim 8, wherein the fifth jaw connector is
oriented orthogonally with respect to each of the first and second
supply side jaw connectors and first and second load side jaw
connectors.
12. The method of claim 8, wherein the fifth blade connector is
orthogonal to each of the first, second, third, and fourth blade
connectors on the first end of the cylindrical body.
13. The method of claim 8, wherein connecting the utility meter to
an opening in a second side of the meter socket adapter comprises
engaging blade connectors of the meter with jaw connectors arranged
along the second side of the meter socket adapter.
14. A meter socket adapter, comprising: a cylindrical housing,
comprising: a first wall defining a plurality of connector
openings, the wall including a first surface arranged along an
exterior of the cylindrical housing and a second surface defining
an interior volume of the cylindrical housing, and a second wall
having a curved geometry and defining a wiring port; a plurality of
connectors extending through the connector openings defined by the
first wall of the cylindrical housing, each of the connectors
comprising: a blade connector protruding from the first surface,
and a jaw connector protruding from the second surface; and a
plurality of terminals positioned within the interior volume and
being configured to connect wires passing through the wiring port
to corresponding ones of the plurality of connectors, wherein one
of the terminals is configured to connect to a neutral wire.
15. The meter socket adapter of claim 14, further comprising a
plurality of clips that keep corresponding connectors secured
within the connector openings.
16. The meter socket adapter of claim 14, wherein the plurality of
connectors comprises five connectors.
17. The meter socket adapter of claim 14, wherein the jaw
connectors are configured to be coupled with blade connectors of an
electric meter.
18. The meter socket adapter of claim 14, wherein the blade
connectors protruding from the first surface are configured to be
coupled with jaw connectors of a meter socket of an electrical
panel.
19. The meter socket adapter of claim 14, wherein the first wall of
the cylindrical housing defines two openings for accommodating a
connector configured to engage a neutral jaw connector in a meter
socket, wherein moving the connector between the two openings
allows the meter socket adapter to be installed in the meter socket
in two different orientations.
20. The meter socket adapter of claim 14, wherein one of the
plurality of connectors is configured to be coupled with a jaw
adapter installed within a meter socket of an electrical panel.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims the benefit of priority under 35
U.S.C. .sctn.119(e) to U.S. Provisional Application No. 62/155,291,
filed on Apr. 30, 2015, which is incorporated herein by reference
in its entirety.
FIELD OF THE INVENTION
[0002] The invention relates generally to power generation and more
specifically to the electrical interface between onsite power
generation systems and existing grid-based commercial and/or
residential power distribution systems.
BACKGROUND OF THE INVENTION
[0003] Onsite power generation has become increasingly popular. For
decades now, particularly in areas that are prone to power outages
and/or for businesses that require uninterrupted power, oil and
diesel backup power systems have been used to generate onsite power
when the grid is unavailable. These systems generate alternating
current (AC) power that ties into a customer's existing power
distribution system, typically on the load side (i.e., between the
utility meter and the main panel) or directly into the main
customer panel. More recently, continuous onsite generation based
on alternative energy sources has increased in popularity.
[0004] Like back-up power systems, onsite alternative energy
generating systems are frequently retrofit into existing structures
which may have electrical systems that are not by default setup to
accept additional energy inputs. One solution to this has been to
wire directly to the bus bars of the customer's main electrical
panel. However, this solution is not ideal because current national
electric code limits the amount of current that can be delivered to
the bus bars to 20 percent of the main breaker's capacity. So this
in turn will limit the maximum capacity of an onsite power
generation system connected in this way.
[0005] To deal with this problem, installers of onsite power
generation systems frequently have to upgrade the customer's main
electrical panel so that it has enough excess current capacity on
the bus bars to accommodate the desired generation system. Then the
power from the onsite generation system can be fed directly into
the main panel and either power the home or business or back feed
power to the grid.
[0006] Another solution to interfacing to existing grid power at
the customer premises has been to utilize a so-called meter socket
adapter or MSA. The MSA fits in between the meter socket in the
customer's existing main panel and the utility company's meter.
Usually the MSA has an opening or input collar to receive the AC
output of an onsite power generation system. This is preferable to
upgrading the main panel because it requires very little labor and
is not affected by the current limitations of the bus bars in the
customer's existing main electrical panel. Two such MSAs are
disclosed in commonly assigned U.S. Pat. Nos. 8,764,130 and
7,648,389, the disclosures of which are hereby incorporated by
reference in their entirety.
[0007] In a typical residential or commercial (e.g., 120V/240V)
system, the meter itself has only two inputs and two outputs--it
does not use the neutral wiring coming in from the utility or
flowing out to the customer's main electrical panel--yet the onsite
power generation system typically has two AC lines plus a neutral
wire. As a result, when interfacing an onsite power generation
system to a customer's electrical panel with an MSA, such as that
disclosed in U.S. Pat. Nos. 8,764,130 and 7,648,389, the neutral
wire has to be run through the MSA, typically through a built in
aperture, so that the loose end can be spliced with the grid
neutral running through the meter socket. This is less than
optimal. First, it requires additional manual wiring to the neutral
through the adapter so that the unconnected adapter is dangling
while the neutral is being wired. Second, after the wiring has been
completed and the adapter connected to the socket, if at any point
the adapter has to be removed, simply pulling it out won't
disconnect it from the meter socket in the electrical panel because
the neutral wire will remain connected and must be manually
disconnected.
[0008] Therefore, there exists a need for a mechanism for
interfacing an onsite power generation system to a customer's power
distribution system that ameliorates the shortcomings of
conventional solutions.
SUMMARY OF THE INVENTION
[0009] This disclosure describes various embodiments that relate to
methods and apparatus for efficiently tying an onsite power
generation system, such as a photovoltaic energy source, into an
existing electrical panel.
[0010] A meter socket adapter for interfacing an onsite power
generation system with an electrical service panel is disclosed.
The meter socket adapter includes the following: a cylindrical body
having a first end and a second end; an opening defined by a
lateral wall of the cylindrical body; a set of four blade
connectors on the first end of the cylindrical body positioned to
connect to four jaw connectors in a meter socket of the electrical
service panel, wherein two of the blade connectors are electrically
coupled to supply terminals for wiring two respective AC supply
lines from the onsite power generation system entering the meter
socket adapter by way of the opening; a corresponding set of four
jaw connectors disposed on the second end of the cylindrical body,
electrically coupled to the respective four blade connectors on the
first end and positioned to mate with four additional blade
connectors of a utility meter; a neutral terminal for attaching a
neutral wire from the onsite power generation system; and a fifth
blade connector electrically coupled to the terminal and disposed
on the first end of the cylindrical body for electrically coupling
the neutral wire of the onsite power generation system to a neutral
jaw connector in the meter socket at the same time that the four
blade connectors mate with the four jaw connectors in the meter
socket.
[0011] In many embodiments, the onsite power generation system
takes the form of a photovoltaic array.
[0012] In many embodiments, the two AC supply lines include AC
phase 1 and AC phase 2 respectively.
[0013] In many embodiments, the four blade connectors of the meter
socket adapter are arranged in a symmetric configuration.
[0014] In many embodiments, the fifth blade connector is arranged
orthogonally with respect to the set of four blade connectors.
[0015] In many embodiments, the cylindrical body defines multiple
openings configured to accommodate the fifth blade connector.
[0016] In many embodiments, the first end of the cylindrical body
has a size and shape in accordance with the standard meter
socket.
[0017] A method of interfacing an onsite power generation system to
an existing electrical service panel with a meter socket adapter is
disclosed. The method includes taking the following actions:
removing a utility meter from a meter socket of the existing
electrical service panel to expose a meter socket; electrically
coupling a fifth jaw connector to a neutral wire terminal inside
the meter socket; connecting at least two AC power supply lines
from an onsite power generation system to respective first and
second load side terminals of the meter socket adapter via an
opening in a side wall of the meter socket adapter; connecting a
neutral wire from the onsite power generation system to a neutral
terminal in the meter socket adapter by way of the opening in the
side wall of the meter socket adapter, the neutral terminal being
electrically connected to a neutral blade connector of the meter
socket adapter; plugging a first side of the meter socket adapter
into the meter socket so that first and second supply side blade
connectors of the meter socket adapter are connected to respective
first and second supply side jaw connectors of the meter socket,
and first and second load side blade connectors of the meter socket
adapter are connected to respective first and second load side jaw
connectors of the meter socket, and the neutral blade connector is
connected to the fifth jaw connector; and connecting the utility
meter to an opening in a second side of the meter socket
adapter.
[0018] In many embodiments, the onsite power generation system is a
photovoltaic array.
[0019] In many embodiments, the at least two AC supply lines
include AC phase 1 and AC phase 2 respectively.
[0020] In many embodiments, the fifth jaw connector is oriented
orthogonally with respect to each of the first and second supply
side jaw connectors and first and second load side jaw
connectors.
[0021] In many embodiments, the fifth blade connector is orthogonal
to each of the first, second, third, and fourth blade connectors on
the first end of the cylindrical body.
[0022] In many embodiments, connecting the utility meter to an
opening in a second side of the meter socket adapter includes
engaging blade connectors of the meter with jaw connectors arranged
along the second side of the meter socket adapter.
[0023] In accordance with other embodiments, a meter socket adapter
includes the following: a cylindrical housing that includes a first
wall defining connector openings, the first wall including a first
surface arranged along an exterior of the cylindrical housing and a
second surface defining an interior volume of the cylindrical
housing, and a second wall having a curved geometry and defining a
wiring port; multiple connectors extending through the connector
openings defined by the first wall of the cylindrical housing, each
of the connectors including: a blade connector protruding from the
first surface, and a jaw connector protruding from the second
surface; and multiple terminals positioned within the interior
volume and being configured to connect wires passing through the
wiring port to corresponding ones of the connectors. One of the
terminals is configured to connect to a neutral wire.
[0024] In many embodiments, the meter socket adapter includes clips
that keep corresponding connectors secured within the connector
openings.
[0025] In many embodiments, there are at least five connectors.
[0026] In many embodiments, the jaw connectors are configured to be
coupled with blade connectors of an electric meter.
[0027] In many embodiments, the blade connectors protruding from
the first surface are configured to be coupled with jaw connectors
of a meter socket of an electrical panel.
[0028] In many embodiments, the first wall of the cylindrical
housing defines two openings for accommodating a connector
configured to engage a neutral jaw connector in the meter socket
and moving the connector between the two openings allows the meter
socket adapter to be installed in the meter socket in two different
orientations.
[0029] In many embodiments, one of the connectors is configured to
be coupled with a jaw adapter installed within a meter socket of an
electrical panel.
[0030] Other aspects and advantages of the invention will become
apparent from the following detailed description taken in
conjunction with the accompanying drawings which illustrate, by way
of example, the principles of the described embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] In order to facilitate a better understanding of the present
disclosure, reference is now made to the accompanying drawings, in
which like elements are referenced with like numerals. These
drawings should not be construed as limiting the present
disclosure, but are intended to be exemplary only.
[0032] FIG. 1 is a perspective view of a conventional main
electrical panel including a utility meter and a meter socket
adapter, according to various embodiments of the invention.
[0033] FIG. 2 is a front view of a conventional electrical panel
showing internal wiring and jaw connectors of the panel's meter
socket.
[0034] FIGS. 3A and 3B respectively show a front view and a rear
view of a conventional digital utility meter.
[0035] FIG. 4A is a system diagram showing components of a
conventional photovoltaic power generation system and a meter
socket adapter interface to main electrical panel at a customer
premises.
[0036] FIG. 4B is a side view of the conventional meter socket
adapter shown in FIG. 4A.
[0037] FIGS. 5A-5B respectively show front and rear views of a
meter socket adapter according to various embodiments of the
invention.
[0038] FIGS. 5C-5D respectively show front and rear perspective
views of a meter socket adapter according to various embodiments of
the invention.
[0039] FIG. 6A shows a front view of a conventional main electrical
panel meter socket adapted to work with the meter socket adapter
according to various embodiments of the invention.
[0040] FIG. 6B shows a perspective view of an alternative
electrical panel meter socket configuration.
[0041] FIG. 7 is a flow chart detailing steps of a method for
interfacing an onsite power generation system to an existing main
electrical panel according to various embodiments of the
invention.
DETAILED DESCRIPTION
[0042] The following description is intended to convey a thorough
understanding of embodiments described by providing a number of
specific embodiments and details involving interfacing a
photovoltaic system to an existing main electric panel. It should
be appreciated, however, that the present invention is not limited
to these specific embodiments and details, which are exemplary
only. Other types of energy collecting systems could interface an
existing main electrical panel in the ways described herein. For
example, both a wind powered turbine or a generator-based onsite
power generation systems could interface with an electrical panel
in the ways described in this disclosure. It is further understood
that one possessing ordinary skill in the art, in light of known
systems and methods, would appreciate the use of the invention for
its intended purposes and benefits in any number of alternative
embodiments, depending upon specific design and other needs.
[0043] As noted above, there is a need for an inexpensive, quick,
yet safe way to interface onsite power generation systems to
existing customer premises' power distribution systems (e.g.,
utility meter and main electrical panel). Various embodiments of
the invention accomplish this with a meter socket adapter that
includes a fifth jaw/blade connector in the adapter. In various
embodiments, the fifth jaw/blade may be used as a terminal for
attaching the neutral wire coming from the onsite power generation
system (e.g., central inverter output). Various embodiments may
utilize a jaw adapter kit wired to the gird neutral wire entering
the socket in the existing meter as a terminal for engaging with
the fifth blade on the meter socket side (e.g., back side) of the
meter socket adapter. In some embodiments, the jaw adapter kit can
be installed on a neutral bridge within the meter socket. These and
other embodiments are discussed in greater detail in the paragraphs
that follows.
[0044] Referring now to FIG. 1, this figure shows electrical panel
100 that includes utility side 110 and customer side 115. Typically
the main breaker and specific circuit breakers are located on
customer side 115 while the incoming utility powerlines, electrical
meter 200 and meter socket 300 are located on utility side 110. In
the system illustrated in FIG. 1, depicted meter socket adapter 300
could be a meter socket adapter according to various embodiments of
the invention. Meter socket adapter 300 includes input connector
310 and section of conduit 315 that carries the conductors from an
onsite power generation system. In some embodiments, the onsite
power generation system is a photovoltaic system that utilizes a
so-called "string" or central inverter. Alternatively, the
photovoltaic system could utilize micro-inverters--miniature
inverters connected to the output of each photovoltaic module or N
modules--in which case a string inverter would not be needed.
Either way, conduit 315 and connector 310 would contain wires
carrying AC power. In various embodiments, this includes phase 1
and phase 2 120 volt or 240 volt AC power as well as neutral and
ground wires.
[0045] It should be appreciated that the invention is not limited
to interfacing a photovoltaic system. Various embodiments of the
invention may be usable with a wind turbine or other onsite power
generation system. The specific type of onsite power generation
system is not critical to the various embodiments of the
invention.
[0046] In the system shown in FIG. 1, and as will be discussed in
greater detail in reference to the remaining figures, in various
embodiments, meter socket adapter 300 is connected to a meter
socket on utility meter side 110 of electrical panel 100 by simply
pulling out electrical meter 200, adding a fifth connector within
the meter socket, plugging in meter socket adapter 300 in its
place, and plugging electrical meter 200 into meter socket adapter
300.
[0047] Turning now to FIG. 2, this figure shows the internals of a
conventional meter socket 112 in a standard electrical panel 100.
Utility wires carrying 120V power (phase 1 AC, phase 2 AC, neutral
and ground wires) typically enter the box either from the top,
bottom or side, of the enclosure where they terminate at respective
connectors so that incoming power can be metered. Typically, the
two live wires will be connected in some fashion to respective
terminals on jaws 122A, and 122B. Jaw connectors are preferred for
this application because they allow a worker to insert a meter or
meter socket adapter with reciprocal blade connectors that are
co-located with the jaws and dimensioned to fit snugly between
them, without having to actually touch the wires. Because the
neutral wire is not connected to the meter in most applications,
the neutral wire from the utility simply terminates at a connector
within meter socket 112, such as terminal 114 shown in the center
of meter socket 112. In this way, the neutral from the grid can be
spliced with the neutral going to customer side 115 of electrical
panel 100. The ground wire is typically wired to a terminal within
meter socket 112. Because the ground wire is securely coupled to a
terminal within the meter socket, the meter socket adapter cannot
be removed without first removing the ground wire from the
terminal.
[0048] As also shown in FIG. 2, jaws 130A and 130B are wired to
respective conductors running out to the bus bars on customer side
115 of electrical panel 100. This wiring is usually concealed
within the body of electrical panel 100 and may come pre-wired to
the bus bars by the panel manufacturer. As clearly seen in FIG. 2,
by inserting a meter, such as electrical meter 200 shown in FIG. 1,
or meter socket adapter 300 and electrical meter 200, the
connection between jaws 122A and 132A and the connection between
jaws 122B and 132B are completed, allowing power to flow to
customer side 115 of electrical panel 100 while also allowing the
utility to monitor the amount of power that flows, typically
measured in units of kilowatt hours or kWh. Also, though not shown
in FIG. 1 or 2, customer side 115 of electrical panel 100 typically
has a hinged door that allows access to the breakers and bus bars
inside.
[0049] Turning now to FIGS. 3A and 3B, these figures show front and
back views, respectively, of electrical meter 200. The front face
of electrical meter 200 typically includes a display such as
digital display 210, illustrating information such as the kilowatt
hours consumed to date and a current number of kilowatts being
drawn through meter 200. Older meters may have a series of dials
counting the kilowatt-hours to date and a spinning wheel that
indicates the rate of current consumption. The various embodiments
of the invention are compatible with either solution.
[0050] FIG. 3B shows the backside of electrical meter 200. Whether
analog or digital, conventional meters typically utilize 4 blade
connectors to bridge the left and right hot wires in the meter
socket of the main electrical service box. For example, blades 222A
and 232A are interconnected through the meter and blades 222B and
232B are also connected through the meter. The position of these
blades is standardized so that meters manufactured by multiple
suppliers will fit with a number of different main panels.
[0051] In some embodiments, electrical meter 200 is pushed into the
socket so that the blades are held captive by the jaws inside the
meter socket with a friction fit. Sometimes there is a pair of
loops--one outside the socket and one on the meter itself--that
enables a small lock or other device to be applied that secures
electrical meter 200 within meter socket 112. In this way,
unauthorized access to the meter can be prevented, thereby
preventing energy from being siphoned off ahead of the meter.
[0052] Referring now to FIG. 4A, this figure shows components of a
PV system utilizing a conventional meter socket adapter. Onsite
energy generation starts with PV array 375 including one or more
photovoltaic modules installed in an array (e.g., on a residential
or commercial rooftop, a fixed ground mount, a sun tracker, etc.).
In many cases, the arrays' positive and negative direct current
(DC) output will be combined into two lines that run to a central
or string inverter such as inverter 350. Alternatively, the modules
may be equipped with one or more micro inverters that perform DC to
AC conversion at the module level or N module levels so that the
power coming out of the array is already AC, obviating the need for
a central inverter. In such cases there will be four lines coming
directly from the array (AC phase 1, AC phase 2, neutral and
ground).
[0053] Typically, though not necessarily, the inverter will be
located near the premises' main electrical service box. As shown in
FIG. 4A, the output of the inverter is wired to meter socket
adapter 300, with AC phase 1 and AC phase 2 being connected to load
side jaw connectors 332A and 332B. Jaw connector 322A and 322B are
operative to pass current entering from jaws 122A and 122B to
electrical meter 200. In such a conventional system, the neutral
wire simply passes through meter socket adapter 300, such as by way
of opening 325, and needs to be wired to a fixed terminal inside
the opening of meter socket 112, such as terminal 114 prior to the
meter socket adapter being installed. Subsequent to securing the
neutral wire to the fixed terminal, the blades on the backside of
meter socket adapter 300 can be mated with corresponding jaws 122A,
122B, 132A, and 132B. Then, electrical meter 200 can be plugged
into adapter 300 to complete the installation. It should be
appreciated that some jurisdictions may require a separate shut off
box between the inverter's output/array output and electrical panel
100.
[0054] FIG. 4B is a side view of conventional meter socket adapter
300 shown in FIG. 4A. Four corresponding blade connectors 340
protrude from the rear of adapter 300 to mate with corresponding
jaws 122A, 122B, 132A, and 132B of meter socket 112. Typically,
though not necessarily, each blade and jaw pair in the meter socket
adapter is a single two-sided connector with a blade on one side
and a jaw on the other side. However, some systems may utilize
two-piece connectors that connect through the socket adapter.
[0055] FIG. 5A shows a meter socket adapter according to various
embodiments of the invention. Socket adapter 400 of FIG. 5A is
illustrated connected to a central inverter-based PV system.
Incoming phase 1 and phase 2 AC lines are connected to respective
jaw terminals 432A and 432B, while jaw terminals 422A and 422B are
both open, serving only to route power from the incoming AC utility
lines to the meter. Terminals 432A and 432B are preferably
positioned on the load side of the meter so that power flowing into
them from the PV system can back feed power to the utility through
the utility meter. In addition, fifth jaw connector 420A has been
added to the socket adapter 400. Fifth connector 420A is used to
provide a wired interface to the third (neutral) line coming from
the PV system. In various embodiments, this fifth connector may be
oriented orthogonally to the other connectors (i.e., rotated by 90
degrees). This improves clearance with respect to the other
terminals. As will be discussed in greater detail with reference to
the remaining figures, having fifth connector 420A advantageously
allows the PV system to be integrated on the load side of the meter
such that pulling adapter 400 from meter socket 112 completely
disconnects the PV system from utility side 110 of electrical panel
100, without any further need for disconnection of any grounding or
neutral wires.
[0056] FIG. 5B shows the backside of meter socket adapter 400--the
side that plugs into meter socket 112 in the main panel. Like
conventional meter socket adapters, meter socket adapter 400 has
four blade connectors 423A, 423B, 433A, and 433B that are
electrically coupled to the four jaws on the front side for
interfacing the jaws in the adapter to the blades on the back of a
conventional meter. In addition, meter socket adapter 400 has a
fifth blade 421A that is electrically connected to connector 420A
which in turn is connected to the neutral wire coming from the
onsite power generation source--in this case a PV array. It should
be appreciated that fifth jaw 420A is optional. All that is needed
is a terminal on the front side to which the neutral wire incoming
from the onsite power generation system can be attached. Jaw 420A
on the front side of meter socket adapter 400 is not utilized by
the utility meter. A screw terminal or other connector will suffice
as long as it is electrically connected to blade 421A.
[0057] Also, although not shown in the figures, it is possible that
the wires from the onsite power generation system may enter meter
socket adapter 400 so that they are wired to the blade connectors
on the back side of the meter socket adapter, rather than the jaws
on the front side, so long as the AC phase 1 and AC phase 2 are
connected to the load-side blades (i.e., the ones corresponding to
the adapter jaws that receive the output of the utility meter when
the meter is connected to the adapter). Also, although not
illustrated, the ground wire coming from the onsite power
generation system would typically be wired to a conductive terminal
built into meter socket adapter 400.
[0058] FIGS. 5C and 5D show perspective views of exemplary
embodiments of meter socket adapter 450, which are similar to meter
socket adapter 400. FIG. 5C shows an interior portion of meter
socket adapter 450 defined by meter socket adapter housing 452.
Meter socket adapter housing 452 can be formed of electrically
insulating material, such as a polymeric material, and can have a
substantially cylindrical geometry. One end of the cylinder shape
of meter socket adapter housing 452 is open so that electrical
meter 200 can be accepted therethrough. FIG. 5C also shows jaw
terminals 420A, 422A, 422B, 432A and 432B which are all disposed
within openings defined by meter socket adapter housing 452 and
designed to interface with blade connector terminals of electrical
meter 200. It should be noted that in some embodiments, electrical
meter 200 can include a fifth blade connector terminal to interface
with jaw terminal 420A in order to provide a neutral and/or
grounding pathway for electrical meter 200. Meter socket adapter
housing 452 can also include a jaw terminal opening 454 that is
sized to receive jaw terminal 420A. This additional opening can
allow meter socket adapter 450 to be reversed with respect to its
orientation when engaging meter socket 112 by moving jaw terminal
420A to jaw terminal opening 454. In this way, a location of wiring
port 456 with respect to an electrical panel can be shifted 180
degrees. Alternatively, two such wiring ports positioned diagonally
from one another may be included in housing 452 to allow for either
configuration. The unused wiring port can be capped with an
appropriate capping mechanism.
[0059] Wiring port 456 is configured to receive wires associated
with wiring connector 310 (see FIG. 1). Wires entering meter socket
adapter housing 452 through wiring port 456 can be electrically
coupled to electrical terminal 458. Electrical terminal 458
includes four ports configured to receive each of the wires
associated with wiring connector 310, namely, positive, negative,
neutral and ground wires. The depicted wires exiting electrical
terminal 458 conduct current from the wires to corresponding jaw
terminals 432A, 432B and 420A. Jaw terminals 422A and 422B don't
need to be coupled as they operate as a simple pass through that
conducts supply side power back and forth between the panel and the
meter. It should be noted that the depicted jaw connectors can also
include stiffening elements bolted to one or more sides of the jaw
connectors. For example, jaw connector 420A includes stiffener 459
bolted to an exterior facing surface of jaw connector 420A.
Stiffener 459 can be adjusted to increase an amount of force with
which jaw connector 420A grabs onto a corresponding blade
connector.
[0060] FIG. 5D shows an exterior surface of meter socket adapter
450. In particular, each of blade connectors 423A, 423B, 433B, 433A
and 421A are depicted. These blade connectors are configured to
engage jaw connectors disposed within meter socket 112. FIG. 5D
also depicts clips 460 that are configured to secure each of the
blade connectors to meter socket adapter housing 452. Clips 460
secure each of the blade connectors by being inserted through an
opening in the blade connector, which prevents the blade connectors
from sliding through corresponding openings in meter socket adapter
housing 452. The blade connectors are prevented from sliding out
the other way on account of a jaw connector end of each blade
connector being too large to slide through the opening
accommodating each blade connector. FIG. 5D also shows optional
protruding alignment features 462 that can be configured to
interact with corresponding features within meter socket 112 to
prevent misalignment between meter socket adapter 450 and meter
socket 112.
[0061] In order to utilize meter socket adapter 400 with a
conventional main electric panel, the existing meter socket 112
will have to be modified with a jaw adapter, such as adapter 602
shown in FIG. 6A. Jaw adapter 602 is mounted within meter socket
112 providing a connector that faces outward and is orthogonal to
the other jaw connectors 122A, 122B, 132A, and 132B and that is
positioned at a fixed location within meter socket 112. In some
embodiments, jaw adapter 602 can be positioned within meter socket
112 so that it is recessed within meter socket 112 the same amount
as the other jaw connectors 122A, 122B, 132A and 132B. Jaw adapter
602 can include an electrically insulated socket base that allows
jaw adapter 602 to be electrically coupled only to the neutral line
bridge. As seen in the example of FIG. 6A, connector 602 provides a
parallel connection to the neutral line bridge between the utility
input and the output to the breaker box on customer side 115 of
main electrical panel 100. In this manner, the onsite power
generation system can be seamlessly, safely and inexpensively
integrated into virtually any main electrical panel at a customer
premises so long as it has a standard-sized meter socket and
utility meter, using only two components--a meter socket with 5
connectors and a jaw adapter--without having to upgrade the
customer's main utility box.
[0062] FIG. 6B shows a perspective view of an alternative meter
socket configuration. In this embodiment, jaw adapter 602 takes the
form of an electrically conductive adapter that is affixed to
support brace 604. Support brace 604 can be designed to provide
structural support for the opening leading into meter socket 112.
In this embodiment, support brace 604 also provides a platform to
which jaw adapter 602 is affixed. Jaw adapter 602 can be affixed to
support brace 604 in many ways. In some embodiments, jaw adapter
602 can be secured to support brace 604 by a fastener 606 that
engages an opening (not depicted) defined by support brace 604.
However, it should be noted that jaw adapter 602 can also be welded
to support brace 604 or affixed to support brace 604 in any way
that results in a solid electrical coupling between jaw adapter 602
and support brace 604. By routing the neutral signal through
support brace 604, which is in turn electrically coupled with
utility side 110 of electrical panel 100, electricity entering
electrical panel 100 from a photovoltaic cell array can be grounded
through electrical panel 100. In many embodiments, electrical panel
100 can be grounded to a metallic stake for additional electrical
protection. In some cases, support brace 604 can be referred to as
a neutral bridge as it provides a pathway for receiving and
distributing the neutral signal from both the upstream power supply
and the photovoltaic power supply. It should be noted that, in
addition to the ways depicted in FIGS. 6A and 6B, the fifth jaw can
be added to the meter socket in any number of ways and that the
depicted embodiments should not be construed as limiting. In some
embodiments, the fifth jaw can be pre-installed at the factory and
be configured to work with a meter socket adapter having a fifth
jaw connector without modification.
[0063] FIG. 7 is a flow chart detailing the steps of a method for
interfacing an onsite power generation system to an existing
customer premises' main electrical panel according to various
embodiments of the invention. The method begins in step 505 where
the existing utility meter is pulled out of the meter socket in the
main electrical panel. As discussed herein, this may involve
removing a lock or other mechanism intended to prevent tampering
with the electric meter. Local code and/or the owner of the utility
meter may also require shut-off of all electric power by the
utility while this is performed. Next, in step 510, a jaw adapter,
such as jaw adapter 602 shown in FIGS. 6A and 6B, is installed in
the existing meter socket. Jaw adapter 602 can be mechanically
connected to the meter socket and will be electrically coupled to
the neutral terminal bridging the utility side neutral with the
neutral running to the breaker panel on the customer side of the
main electrical panel. This may be done on the left or right side
or even at some other position, depending on the desired mating
location with the blade of the meter socket adapter.
[0064] Next, in step 515, the meter socket adapter with five blade
connectors is plugged into the meter socket so that the fifth blade
on the backside of the meter socket adapter mates with the fifth
jaw in the meter socket. Then, in step 520, the wires from the
onsite energy generation system (e.g., PV system) are wired into
the meter socket adapter. In various embodiments, this will involve
physically coupling a section of conduit containing the conductors
from the onsite energy generation system using a connector (e.g.,
snap-in connector, threaded connector, etc.) into a wall of the
meter socket adapter and connecting the free ends of the conductors
to respective terminals in the meter socket adapter creating a
parallel tap to each conductor in the meter socket on the load side
as well as wiring the ground wire to the adapter.
[0065] It should be appreciated that in various embodiments, the
order of steps 515 and 520 may be reversed. That is, it may be
desirable to fully wire the onsite power generation system to the
meter socket adapter first (AC 1, AC 2, neutral, and ground),
before plugging it into the meter socket. This may be safer and
easier than doing it after the meter socket adapter has been
plugged into the meter, in particular, because some manipulation of
the meter socket may be required to mechanically attach the conduit
containing the conductors to the meter socket adapter.
[0066] Finally, in step 525, after the meter socket adapter is
fully wired and plugged into the existing meter socket, the utility
meter is plugged into the meter socket. Once utility power is
restored, the meter will operate as if the meter socket adapter is
not present, with the exception that when the onsite power
generation system is producing excess power (power that is not
being consumed by loads attached to the main electrical power), the
parallel tap on the load side facilitated by the meter socket
adapter will allow power to backflow through the meter to the grid,
either slowing the rate at which the meter is incrementing or
causing it to increment backwards.
[0067] Also, in various embodiments, it may be desirable to wire
the onsite power generation system to the meter socket adapter
first (step 520), before the meter is even pulled (step 505) in
order to minimize the time that utility power must be turned off.
In that case, after step 520 is performed, the meter will be pulled
(step 505), the fifth jaw adapter will be installed in the socket
(510), the meter socket adapter will be plugged into the socket
(515) and the meter will be plugged into the meter socket adapter
(525).
[0068] The embodiments of the present inventions are not to be
limited in scope by the specific embodiments described herein. For
example, although many of the embodiments disclosed herein have
been described with reference to interfacing a photovoltaic system
with an existing main electrical panel, the principles herein are
equally applicable to other types of onsite power generation
systems (e.g., wind). Indeed, various modifications of the
embodiments of the present inventions, in addition to those
described herein, will be apparent to those of ordinary skill in
the art from the foregoing description and accompanying drawings.
Thus, such modifications are intended to fall within the scope of
the following appended claims. Further, although some of the
embodiments of the present invention have been described herein in
the context of a particular implementation in a particular
environment for a particular purpose, those of ordinary skill in
the art will recognize that its usefulness is not limited thereto
and that the embodiments of the present inventions can be
beneficially implemented in any number of environments for any
number of purposes. Accordingly, the claims set forth below should
be construed in view of the full breath and spirit of the
embodiments of the present inventions as disclosed herein.
* * * * *