Breakaway connector and fuse receptacle

A mast lighting system of the type including at least one mast having a proximate end and an opposite distal end, the distal end capable of supporting an electrical component and the proximate end mounted to a foundation that has at least a portion extending into the ground, an electrical cable within the mast connecting the electrical component to a distribution component assembly through a breakaway electrical connector, and a power source connected to the distribution component assembly. The breakaway electrical connector including a fuse in a first part and a fuse clip in a second part forming the breakaway connection between the two parts of the electrical connector.

BACKGROUND OF THE INVENTION

This invention relates to the general field of electrical connectors and is particularly concerned with outdoor mast lighting systems.

Mast lighting systems are well known and commonly support a light above the surface to be lighted with a long pole or mast. Masts are typically hollow, and may be round, square or of any selected cross-sectional shape which provides adequate stability. The mast may include a breakaway base at its lower end having an opening (or “handhole”) therein, through which the interior of the mast may be accessed by maintenance or installation personnel. The mast is typically mounted on a foundation of concrete or other suitable material set permanently into the ground and may be affixed to the foundation by a plurality of anchor bolts set into the foundation, which engage corresponding holes in the breakaway base.

Suspended at the top of the mast is an electrical component, commonly an electric light. In some applications, a cantilevered secondary mast or arm supports the light over a street or sidewalk. In other applications, a ring of high-intensity lamps may be supported radially around the distal end of the mast. The electrical component is electrically connected to a power source, generally in series with a number of other commonly powered mast units in a given area.

Power delivery to each light in a commonly powered system has been accomplished in a variety of ways. In one such system, the output of a master circuit breaker may be connected to an electric power cable which runs to the base of the mast. The power cable may connect to a fuse and surge arrestor assembly disposed within the hollow mast, which prevents current surges caused by lightning, voltage spikes or other anomalies from damaging the light fixture or the master circuit breaker. Access to the fuse and surge arrestor assembly is commonly provided by locating that assembly adjacent a handhole in the mast.

The performance of such a system is impaired by several shortcomings. Wire and cable attachments are generally made by splices, which are vulnerable to failure when tensile forces are applied to the connections.

In the event of an impact, the mast is often sheared off at the base and commonly comes to rest several yards from its original position. As is evident, the electrical circuit within the mast must be provided with means of disconnect which will allow the load side to separate from the line side by means of suitable tension applied to the load side conductors in the event a mast knockdown were to occur due to impact from a vehicle, thus preventing the feeder circuit being unearthed or broken; disrupting power to the rest of the circuit, which would be very important in the event of a nighttime accident; leaving broken or frayed electrical conductors exposed providing potential for electrocution to persons at the accident site; and energized electrical wires falling into traffic or the accident vehicle(s). In addition to these features, a fuse should be provided for protection of the load circuit, and in the event of a problem in the load circuit, the fuse would open, leaving the remainder of the lighting circuit energized.

Of particular importance, since this type of connector must be accessible for maintenance, is that the fuse be installed in such a manner that maintenance personnel are at no risk of electrical shock during fuse inspection or replacement. A further requirement for this application is that the connector be watertight, as certain conditions could occur, causing the connector to be submersed in flood water. Further, the connector should be easily assembled and serviced by technicians and capable of being capped on-site in the event of a mast knockdown.

SUMMARY OF THE INVENTION

These and other shortcomings in the prior art have been addressed by one or more embodiments of this invention which includes an electrical connector which will separate safely upon impact or tension of the adjoining wired connections. In various embodiments, the connector may be fused or unfused depending upon the particular application.

Roadway lighting masts or poles are mandated to breakaway at the base during impact. This type of light pole also requires an inline breakaway connector to be installed. This invention in various embodiments is such an inline breakaway connector which may be used in such settings. Additionally, fusing these connectors helps prevent any unintended electrocution. It is estimated that of the approximately 60 million street lights in the U.S.A., 26 million are roadway lighting and subject to breakaway regulations.

Connectors according to this invention may also be utilized for roadway lighting, parking lighting, electric vehicle charging stations, solar installations, traffic signals, lighted signage, LED conversion, sports lighting, and marine lighting to name just a few non-limiting examples.

The breakaway connector according to various embodiments of this invention may be utilized without allowing for voltage exposure. In various embodiments, mechanical screws are used to lock a fuse in place to the load side of the connector thereby providing a safer connection than with many prior art breakaway connectors. This invention also is easier to install because it includes fewer parts and therefore takes less time and space for installation. Moreover, it also minimizes the chance of incorrect installation. Conductors or stranded wires are inserted into the connector for easier installation and assembly. Various embodiments of this invention are also water resistant or waterproof.

Various embodiments of the connector according to this invention include caps which could be used to seal or isolate voltage and prevent inadvertent electrocution after a light pole impact or separation. The caps may be tethered to the entry points for the conductors and after impact, the cap may be removed and placed on the line side open to a voltage exposure. The same cap may also be used for sealing set screw access to the connector.

According to various embodiments, the connector of this invention utilizes two independent components which have modular design with the ability to be configured into six or more different products. This allows the connector to be converted in the field should regulations change from a non-breakaway device to a breakaway device with the addition of only one or a minimal number of parts. This connector may be utilized underground or in a submersible environment, allows for range taking and breakaway operation and may include a fuse, if appropriate. This connector may be manufactured from high-strength, 6061-T6 aluminum alloy and be rated for boo volts as well as certified for direct burial in earth or concrete and submersion applications and meet or exceed UL486A, B, D and ANSI 119.1 and 119.4 specifications.

These and other aspects of various embodiments of this invention overcome the shortcomings of the prior art and are shown in more detail in the accompanying drawings and following detailed description.

DETAILED DESCRIPTION OF THE INVENTION

Referring first toFIG. 1, a mast lighting system10is shown, of the type having at least one mast12mounted to a foundation14. At least part of the foundation14extends below the grade16of the surrounding ground18, whether installed in a parking lot, highway shoulder, sidewalk, or other environment. The foundation14commonly includes a pedestal20of concrete, but may be constructed of other materials capable of providing a stable base for the lighting system10. The horizontal upper surface of the pedestal20may be at or above the level of the surrounding grade16. The pedestal20may be poured around a central conduit22through which underground electrical feeder wires24,26extend. The incoming feeder wires24convey electrical power to the lighting unit, either from a common power source (a remote circuit breaker box28) or from the outgoing feeder wires26of an adjacent lighting unit (not shown).

The mast12is rigidly attached to the pedestal20by welding, by a plurality of anchor bolts, or other standard connections. The mast12is commonly constructed of tubular aluminum, but may be of any suitable material, including concrete, steel or fiberglass. The mast12may also be of any selected cross section, including circular or square. The mast12is capable of supporting an electrical component30. The electrical component30may be a standard street lamp32, a high-watt high mast lighting system (not shown), or other desired device. An electrical cable34connects the electrical component30to a distribution component assembly36. The electrical cable34is preferably sized for standard mast height and runs the length of the mast12through its hollow interior. Other embodiments of the electrical cable may be utilized, including commercially available mast lighting cables (not shown), or even a simple 3 wire cable having 14 gauge conductors (not shown).

The distribution component assembly36may be located within a chamber38. Location of the distribution component assembly36within the chamber38may provide optimal protection from side impact damage due to traffic accidents or other collisions.

In one embodiment, the central conduit22may be constructed of pressure treated cylindrical PVC tubing or galvanized rigid steel piping of 6″ diameter. In this embodiment, the central conduit22may have an access hole40there through to allow passage of the incoming and outgoing feeder wires24,26into the chamber38. The foundation14may form the lower boundary of the chamber38. Horizontal rebar (not shown) may be provided extending into the surrounding pedestal20for securing the central conduit22after the concrete sets.

The distribution component assembly36may include, in one embodiment, a surge arrestor and one or more electrical connectors44(seeFIGS. 2-5) which connect(s) the distribution component assembly36to the electrical cable34. Individual components may be connected via standard wiring, with or without the use of contact blocks (not shown) mounted to a board (not shown). Standard fuses may be utilized, whether free standing or contained in an integrated externally accessible fusing assembly, described in further detail below. Commercially available components from a variety of manufacturers may be utilized in the distribution component assembly36, such as fast-acting type axial fuses and surge arrestors.

The mast12, near the proximate end35which may be above the foundation14, defines an opening or handhole42, through which the chamber38is accessible by the user. The handhole42may extend through the main body72of the mast12itself, or through a breakaway cover46on the mast12at its proximate end35. The location of the opening or handhole42should be near enough to the foundation14and chamber38therein that the distribution component assembly36is accessible by hand to maintenance or installation personnel, thereby simplifying routine maintenance and repair to be performed on the mast lighting system10. The handhole42may be covered between repairs or maintenance by the cover or door46.

In one embodiment, the electrical connector44in the assembly36between the feed wires24,26and the electrical cable34is a watertight breakaway connector. The breakaway connector44preferably disengages under tension, such as when a mast12fails due to vehicular impact. In any event, the tensile force required to disengage the breakaway connector44is less than the tensile force necessary to damage the electrical cable34or electrical connections thereto. When the breakaway connector is properly mated and locked, it preferably forms an enclosure which meets the local municipal and other requirements.

Referring toFIGS. 2-5, various embodiments of a breakaway connector44according to this invention are shown. A first embodiment of the breakaway connector44is shown inFIGS. 2-4and a second embodiment consistent with the principles of this invention is shown inFIG. 5. The first embodiment ofFIGS. 2-4of the breakaway connector44includes two rigid metal bodies48a,48b, (first and second parts) one of which is a load side metal body48aand the other which is a line side metal body48b. The load side metal body48ais coupled to the electrical cable34extending through the mast coupled to the light or load32. The metal body48bon the line side is coupled to the incoming feeder wire24on the voltage side of the electrical connector44. Each metal body48may include a top surface, a bottom surface and opposed sidewalls that are continuous with the top and bottom surfaces. In various embodiments, each metal body48has a substantially rectangular cross-sectional profile.

Each metal body48includes a conductor receiving bore50extending longitudinally into the metal body48on one end thereof. Each conductor receiving bore50is adapted to receive a stranded conductor or other wire. The stranded conductor may be the incoming feed wire24or the electrical cable34and if it is a stranded conductor comprises a compacted bundle of individual strands of an electrically-conducted material such as copper or aluminum. Each conductor receiving bore50is generally cylindrical and has a circular cross section of a radial dimension adequate to receive the conductor therein. Each conductor receiving bore50is disposed substantially orthogonally to the planes defined by the sidewalls of the metal body48.

A threaded bore52extends downwardly through the top surface of each metal body48and communicates with the interior of the associated conductor receiving bore50. A longitudinal axis of the threaded bore52is disposed substantially orthogonal to a longitudinal axis of the conductor receiving bore50. The threaded bore52includes a continuous helical thread54disposed along a substantial portion of the interior surface of the bore52. Each threaded bore52a,52breceives therein a binding fastener such as a binding screw56removably received within the threaded bore52. Each binding screw56may include a generally conical tip58having a slightly blunted extremity of a small radius of curvature and an inclined surface60relative to the plane tangent to the blunted extremity so that the contacting strands of the stranded conductor will be induced to slidably deflect there along. In addition, the conical tip58encourages strands to rub together and remove oxidation from the surfaces thereof so that the quality of the electrical connection is improved.

To facilitate insertion into the threaded bore and subsequent tightening, the binding screw56has a shaped recess62for receiving a corresponding-shaped tool (not shown). Recess62and tool removably receivable therein may have a hex-type or Allen-type connection. Other configurations of binding screw56are possible such as a binding screw having a slotted head or a Phillips-type head which can be tightened with an ordinary screwdriver.

Each metal body48may be formed by extrusion or any other known method of metal fabrication. Each metal body48may be composed of an aluminum alloy and, for the sake of compatibility during thermal cycling, the binding screw56and the electrical connector44may be composed of similar aluminum alloys.

As shown inFIGS. 2-4, the load side metal body48aalso includes a second threaded bore52cextending downwardly through the top surface of the metal body48a. This threaded bore52cis in communication with a fuse receiving bore64extending longitudinally from an opposite end of the metal body48aon which the conductor receiving bore50ais located. As the name implies, the fuse receiving bore64is adapted to receive one longitudinal end of a fuse66inserted therein as shown particularly inFIGS. 3-4. So as to properly position the fuse66seated within the fuse receiving bore64of the load side metal body48a, the fuse receiving bore64may also house a plug68in the terminal end of the bore. The threaded bore52cis in communication with the fuse receiving bore64and extends downwardly through the top surface of the metal body48a. A longitudinal axis of the threaded bore52cis disposed substantially orthogonal to a longitudinal axis of the fuse receiving bore64and includes a continuous helical thread54disposed along a substantial portion of the interior surface thereof. A binding screw56is removably received within the threaded bore52cso as to selectively secure the fuse66to the load side metal body48awhen seated therein. The tip61of the binding screw56in the bore52cmay be blunt or flat for contact with the fuse66.

A fuse clip receiving bore70is formed in the line side metal body48bextending longitudinally from an end of the metal body48bopposite from the conductor receiving bore Sob therein. A threaded bore52dlikewise extends downwardly through the top surface of the line side metal body48band communicates with the interior of the fuse clip receiving bore70. A longitudinal axis of the threaded bore52dis disposed substantially orthogonal to the longitudinal axis of the fuse clip receiving bore70and includes a continuous helical thread54disposed along a substantial portion of the interior surface thereof. A binding screw56is removably received within the threaded bore52d. The binding screw56and fuse clip receiving bore70are adapted to selectively secure a fuse clip72in the fuse clip receiving bore70such that the fuse clip72extends longitudinally from the end of the line side metal body48bas shown inFIGS. 3 and 4. The fuse clip72may have a generally tubular configuration with a longitudinally extending tang74projecting into the fuse clip receiving bore70on a bottom portion thereof opposite from the threaded bore52d. The tang74may have a semi-circular cross-sectional shape so as to conform to the configuration of the fuse clip receiving bore70and still provide access for insertion of the binding screw56to secure the fuse clip72to the line side metal body48b. The distal end of the fuse clip72has a generally annular configuration, projects from the metal body48band is adapted to receive an end of the fuse66projecting from the load side metal body48bas shown inFIG. 3. The distal end of the fuse clip72includes an annular lip76which is compatible with an end of the fuse66extending from the fuse receiving bore64in the metal body48a. The lip76on the fuse clip72mates with an annular shoulder on the fuse66as shown inFIG. 3to thereby complete the electrical circuit between the electrical bodies48when the components of various embodiments of this invention are assembled as shown inFIG. 3.

Each of the metal bodies48may be encased in plastic, rubber or other protective and non-conducting coating78substantially enveloping the metal body48on all sides. The insulating cover may be of any color and in various embodiments is black or clear plastic. The coating78may be polyvinyl chloride and include passages80for receiving the conductors, binding screws, fuse and fuse clip components of the electrical connector44according to various embodiments of this invention. The passages Boa of the cover78are formed upwardly extending from the top face of the metal body48and aligned with the threaded bores52for the binding screws56to pass there through and into the threaded bores52. The passages Bob on the longitudinal ends of the metal bodies48allow for the passage of the conductors into the conductor receiving bores50. Passages80c, Sod are for the fuse receiving bore64and the fuse clip receiving bore70as shown generally inFIGS. 3 and 4. The inner surfaces of the passages Bob in communication with the conductor receiving bores50may have a tiered step configuration82, referred to as a rocket-shaped configuration in the industry, to receive and focus the strands of a multi-strand conductor being inserted therein and into the conductor receiving bore50of the metal body48.

The shape, design and configuration of the passages80c,80dassociated with the fuse receiving bore64and fuse clip receiving bore70on the compatible metal bodies48a,48bare intended for mating the metal bodies together as shown generally inFIG. 3. The male plug and female socket interconnection relationship between the passages80c,80dfor the fuse on the fuse clip are shown particularly inFIG. 3. The male/female interconnection between the passages80c,80don the fuse receiving bore64and fuse clip receiving bore70provide for a water-tight breakaway connection between the covers78surrounding the metal bodies48. The connector44may also be sealed against salt and UV light by the cover78. Moreover, each of the passages may include a cap84connected to a tether86coupled to the cover78for selectively closing and sealing the associated passage80thereby further providing for a moisture seal for the electrical connector44. The various caps84associated with the passages80may be interchangeable such that one cap may be removed and reinstalled on a different passage on the same or different metal body48.

Referring toFIG. 5, another embodiment of the connector44according to this invention is shown in which the load side metal body48ais oriented generally perpendicular to the line side metal body48b. The metal body48aof this embodiment includes a pair of conductor receiving bores50a,50a, each of which is adapted to receive an electrical cable34with the fuse receiving bore64positioned therebetween. Each conductor receiving bore50a,50ahas a passage80associated therewith for passage of the electrical cable34into the metal body48a. In other embodiments of this invention, any number of conductor receiving bores50acould be included on the metal body48a. Similarly, multiple conductor receiving bores50bcould be included on the metal body48bin alternative embodiments of this invention. Moreover, multiple fuses may be accommodated in various embodiments of the connector44.

A further alternative embodiment of the connector44according to this invention is shown inFIG. 6which is similar to the view of the embodiment shown inFIG. 3. The embodiment ofFIG. 6includes two fuse clips72,72each seated in one of the fuse related bores64,70to retain the fuse66in the assembled connector44. While each of the fuse clips72may be of similar design to one another, in some embodiments one of the fuse clips may include a feature to retain the fuse66with the associated portion of the connector44upon separation of the connector44. The fuse66and each fuse clip72may be collectively or generally referred to herein as a fuse component. Each binding screw56in the respective body48a,48bmay secure the tang74of the associated fuse clip72to the body48a,48bas shown inFIG. 6.

Use of a breakaway connector44in the mast lighting system10prevents broken wires and de-energization of a complete circuit when one component such as a mast12fails. The breakaway connector44separates safely under tension, eliminating danger and electrical shock. When it comes time to replace a failed mast12, the existing electrical cable34can be re-used or replaced without replacing the underground feeder wires24,26distribution component assembly36or the breakaway connector44. A breakaway connector44, which is rated for 15 amps, 480 volts, and which safely disengages under a tension of 7.5 lb may be employed. The connector44may disengage at the fuse juncture and/or at either or both conductor junctures.