Patent Publication Number: US-7905748-B2

Title: Temporary connect

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application 61/070,825 filed Mar. 26, 2008. 
    
    
     BACKGROUND 
     1. Field of the Invention 
     This invention relates to providing electrical power to a structure under construction or other construction site and more particularly to a temporary connect for providing electricity to the completed wiring system of a structure via a common extension cord. 
     2. Description of Related Art 
     At a typical construction site, there is a temporary power source on site to provide electrical power for construction purposes. For example, a temporary power pole, including a temporary meter, may be used. When the project is close to completion, a permanent electrical meter loop configured to accept a permanent power connection is installed. On many locations this permanent power meter is not installed until construction is substantially complete. At that point, the utility company will install the power meter and make the final power connection. 
     Electricians who wish to test lights, circuits, or other electrical devices in the structure must sometimes wait until a permanent meter is installed, or find another means to temporarily power the structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front elevation view of a standard meter cabinet equipped with a temporary connect; 
         FIG. 2  is a cutaway side view of a standard meter cabinet equipped with a temporary connect, more particularly showing a safety release mechanism; 
         FIG. 3  is an electrical block diagram showing the connections of the electrical components; 
         FIG. 4  is a perspective view of an exemplary form factor for a temporary connect; 
         FIG. 5  is a bottom view of a base including mounting terminals and a neutral terminal; 
         FIG. 6  is a front view of a meter cabinet usable with a temporary connect; and 
         FIG. 7  is a side view of a construction site showing an exemplary application of a temporary connect. 
     
    
    
     SUMMARY OF THE INVENTION 
     A temporary connect enables a structure to receive electrical power via a simple extension cord before a utility meter is installed. The temporary connect incorporates the form factor of a standard power meter and mounts to the meter cabinet. It includes a standard male connector or breaker, fuse or lug recessed within a base. A female end of an extension cord may be plugged into the male connector, and the opposite end may be plugged into a temporary meter pole or other power source. The temporary connect connects the prongs of the connector to the load leads of the meter cabinet, but isolates the connector and load prongs from the line leads. The structure thereby can easily receive power for testing the circuits, lights, and other devices. When construction is complete, the temporary connect can be easily removed and replaced with a permanent power meter. 
     In another aspect of this device, a breaker, fuse and/or lugs matched to the correct voltage and phase are used to provide the connection for the temporary connect. A breaker may be provided as an integral part of this device in any of its forms. The breaker may be interchangeable and the device may be adapted for use with any load. 
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     A temporary connect provides a simplified means of powering a structure or other construction site before construction is complete and a final permanent power connection is made. The temporary connect provides a connection point, such as a male connector, which it electrically couples to the load terminals, thereby providing power to the structure or site. It also electrically isolates the load terminals from the line terminals, thereby electrically insulating the site from the permanent power source. This allows power to be routed from a temporary power generator, temporary pole, or other source via a simple extension cord properly equipped with the appropriate NEMA electrical connector. Furthermore, a temporary connect may use the same form factor as a permanent power meter. Because of this novel configuration, a qualified electrician may make a safe connection to the meter cabinet at any time without a permanent power meter being provided. 
     By providing the ability to easily connect and disconnect power to the site, the temporary connect allows those working on the site to easily perform a number of tasks. For example, an electrician may test and balance circuits and ensure that the electrical system is working properly. With the electrical system tested, other work crews can perform their tasks. For example, an air conditioning system can be charged and tested. Lights, trim, dry wall and other interior work crews can use the temporary electrical power to operate their power tools, and lighting can be provided for night work. When the structure or site is finally complete, there is no need for the electrician to return to finally install the permanent power meter. Because of the modular design of the temporary connect, it has the same form factor as a permanent power meter. It can be ejected from the meter cabinet (without any need of specialized electrical training or tools) and replaced with the permanent power meter. 
     Another aspect of the present specification is an enhanced safety mechanism in the form of a safety release switch. A safety release switch can be provided either as part of the temporary connect or as part of the electrical connector. The safety release switch may be biased to an open or disconnected position and configured to release the electrical connection from the temporary connect whenever in the open position. When the front cover of the meter cabinet is closed, the safety released switch is engaged in a closed or connected position. This allows the temporary connect to be connectively seated within the meter cabinet and for the electrical connections to be complete. In this manner, it can be assured that the temporary connect will never energize the structure or site when the meter cabinet cover is off, thus providing for additional safety. 
     A temporary connect will now be described with more particular reference to the attached drawings. 
       FIG. 1  illustrates a meter cabinet  106  equipped with a temporary connect  100 . The temporary connect  100  includes an electrical connector  104 , which in some embodiments may be protected by an in-use weather proof cover (not shown). Electrical connector  104  may provide any multi-prong configuration, and in particular may be one of a number of NEMA standard connectors. In some embodiments, connector  104  will provide a configuration suitable for a 220-volt alternating current input. The electrical connector  104  is located within a base member  102 . The electrical connector  104  may be a male adapter, breaker, lug, or fused device/connector, and may be recessed within base member  102 . There is also shown a safety release switch  108  which is engaged in a closed position by a meter cabinet cover  112 . Finally, there is shown a locking tab  110  which allows the meter cabinet to be locked. 
       FIG. 2  shows a side view of a meter cabinet equipped with a temporary connect, more particularly showing the operation of the safety release switch  108 . There can be seen in this view safety release switch  108  which may be biased in an open position by spring  202 . There is also shown an exemplary circuit including positive node  204  and negative node  206 . When safety release switch  108  is held in a closed position by meter cabinet cover  112 , then positive node  204  and neutral node  206  are connected and the temporary connect  100  is operable to provide electrical power to the structure or site. When meter cabinet cover  112  is opened, safety release switch  108  is biased to an open position by spring  202 , thereby breaking the connections between positive node  204  and negative node  206 . This ensures that at any time, when the meter cabinet cover  112  is open, no power will be provided to the site. 
     In other embodiments, instead of a mechanical switch, other types of disconnect mechanisms may be used. For example, the switch may be a solid-state switch, a proximity switch, a relay, or any other mechanism adapted to disconnect power in the presence or absence of an input. 
       FIG. 3  is an electrical block diagram of an exemplary embodiment of a temporary connect. Connector  104  includes a neutral prong  320 , load prong  322 - 0  and load prong  322 - 1  (each providing a separate power phase), and a ground prong  324 . Load prongs  322  interface with spring switch  108 , so that the electrical connection is broken when the switch opens. When spring switch  108  is closed, load prong  322 - 0  is connected to load  302 - 0  (Z 0 ) and load prong  322 - 1  is connected to load  302 - 1  (Z 1 ). The mechanical interfaces for these connections are between load terminals  510  ( FIG. 5 ) and load brackets  630  ( FIG. 6 ). In the depicted embodiment, load prongs  322  provide 220V two-phase power, though any suitable power configuration would work. For example, with a different connector, and with an additional pair of terminals and an additional prong, three-phase power could be provided. The appropriate power configuration may depend on the design of the structure and the type of power source available. 
     Loads  302  have a return path through neutral node  312 , which in some cases may be grounded to ground node  310 . Temporary connect  100  also includes two line terminals  520 , which mechanically interface with line brackets  620  ( FIG. 6 ). Line brackets  620  ( FIG. 6 ) provide an electrical connection to a line source  330 , which may be a permanent power service connected to a power utility. In permanent operation, an electrical meter would connect loads  302  to line terminals  520 , so that power is supplied to the structure from line source  330 . But temporary connect  100  electrically isolates line terminals  520 , so that no power is drawn from line source  330 . Instead, power may be supplied by a temporary source, such as a temporary pole or a generator, through connector  104 . 
       FIG. 4  is a perspective view of a temporary connect  100 , more particularly demonstrating the form factor, and showing that connector  104  may be recessed within base  102  with an in-use weather proof cover  105  also housing the safety switch  108 . Base ring  410  is made of conductive metal, and may serve as a chassis ground point for temporary connect  100 . 
       FIG. 5  is a perspective view of a temporary connect showing base  102 . Also seen in this view are load terminals  510  and line terminals  520 . Load terminals  510  may be made of a heavy-gauge conductive material, such as aluminum. Line terminals  520  may also be made of conductive material, as they commonly are in permanent electrical meters. But because one of the functions of temporary connect  100  is to isolate load terminals  510  from line terminals  520 , in some embodiments, line terminals  520  may be made of a heavy-duty insulating material such as a strong plastic or composite, thus providing additional insulation. In embodiments where line terminals  520  are made of conductive material, they will, within temporary connect  100 , be unconnected to the rest of temporary connect  100  and may have a coating of insulating material. Also visible in this view is neutral terminal  530 , which is electrically connected to neutral node  312 . 
       FIG. 6  is a front view of an embodiment of a meter cabinet  106  usable with a temporary connect  100 . Meter cabinet  106  includes a sturdy chassis  640  for mounting to a support surface, such as a wall or electrical pole. Contained within chassis  640  is a meter socket  610  adapted to receive a temporary connect  100 . Meter socket  610  includes load brackets  630  and line brackets  620 . Load brackets  630  are configured to securely receive load terminals  510  ( FIG. 5 ). Load brackets  630  are electrically connected to the site, so that when load brackets  630  are powered, the site receives power. Neutral lug  680  connects to neutral terminal  530  ( FIG. 5 ) to provide the neutral node  312 . Ground standoffs  660  are connected to ground  310 , which may be an earth ground. Ground standoffs  660  are configured to electrically and mechanically couple to base ring  410 . 
       FIG. 7  is a side view of a construction site showing an exemplary application of a temporary connect  100 . A site under construction, such as a structure  710 , includes load circuits  302 . The site is provided with a meter cabinet  106 , which may modularly receive either a temporary connect  100  or a permanent electrical meter. Load brackets  630  are connected to load  302 . Line brackets  620  are connected to cabling  722 , which may be protected by a conduit  712 . Cabling  722  runs underground to electrical pole  720  and connects to transformer  760 , which receives power from power lines  750 . When construction is complete and a permanent electrical meter is installed in meter cabinet  106 , power will be supplied through cabling  722 . But with temporary connect  100  installed, line brackets  620  are electrically isolated from load brackets  630 . Load brackets  630  are electrically connected to connector  104  ( FIG. 1 ). A female end of 220-V extension cord  734  is plugged into male connector  104  ( FIG. 1 ). The opposite end of extension cord  734  is plugged into an outlet at temporary meter  732 , which is mounted on temporary pole  730 . Temporary meter  732  may receive power from a connection to a power utility, or from another source such as a generator or battery source. As shown, power is temporarily routed from temporary meter  732  through extension cord  734  to temporary connect  100 , and is thus provided to structure  710 . When construction is complete, temporary connect  100  can simply be removed from meter cabinet  106  and a permanent meter can be installed in its place. The permanent meter will make the connection between load bracket  630  and line bracket  620 , thus providing permanent, metered power to structure  710 . Because the replacement of temporary connect  100  with a permanent electrical meter is merely a matter of unplugging one and plugging in the other, it may be able to be performed by someone other than a licensed electrician. 
     While the subject of this specification has been described in connection with one or more exemplary embodiments, it is not intended to limit the claims to the particular forms set forth. On the contrary, the appended claims are intended to cover such alternatives, modifications and equivalents as may be included within their spirit and scope.