- Creado: 21212121-0909-0101
- Última sesión: 21212121-0909-0101
Perfil del usuario
Descripción: Junction boxes are metal or plastic enclosures used as housings for wiring connections. The connections within are called branch circuits and usually represent the end of a conduit run. Junction boxes make wire access easy, since all one must do is remove the covering to make alterations, repairs, or additions to a conduit. Junction boxes also protect wiring from the elements or environment, which can sometimes be corrosive or otherwise harmful to wiring material. Finally, junction boxes protect wiring from unwanted tampering, whether malicious or unintentional. Junction Box Wiring Basics Essentially, a junction box houses wire connections in order to split off power from a single source to multiple outlets. For instance, a junction box might contain one wire power source that is connected through multiple wires to power several different lights. Electrical junction boxes are usually between 2 ? to 3 ? inches long and made of metal or hard plastic. The functional difference between plastic and metal depends whether or not the junction box is supposed to support any weight. Some metal junction boxes can support light fixtures; plastic junction boxes cannot withstand this weight. Additional differences include installation, in that plastic IP65 junction boxes are typically quicker and easier to install than metal ones. However, a standard junction box designed to simple cover wire splices can be either metal or plastic. Wire Splices in Junction Boxes All wire splices must be contained within a junction box for a building to meet electric code, although sometimes splices are missed and may present hazards as a result. Any exposed wiring can be dangerous, but exposed wire splices are especially prone to accident because they can be tripped over, expel sparks or misrepresent themselves be misperceived as playthings by children or pets. Junction boxes are helpful for wire splices because they also allow one to easily locate the wire splice area. Waterproof junction boxes provide an important function of providing a safe transition of power produced from the photovoltaic (PV) cells in the laminate to the external wiring system for interconnecting modules and loads. Electric distribution boxes, also referred to as “jboxes,” are used in a wide variety of electrical applications and serve to protect the connections between wires and cables. In a PV module, however, the jbox also houses the bypass diode that provides a PV cell-protective function and it is prewired and terminated for rapid interconnection of modules in the field. The junction box enclosure consists of a body enclosure and lid both of which are almost exclusively made of injection-molded polymeric construction and are adhered to the substrate of the module with an adhesive compatible with both the junction box polymer and PV module substrate. The combination of the enclosure, bypass diode, transitioning wiring, connectors, and adhesive makes the jbox a complex component that appears deceptively simple and is not designed to be maintained or serviced. This combination of system behavior and lack of maintainability poses a reliability challenge for the PV module manufacturer, where a service lifetime of 25-years is expected. The importance of design, characterization of the failure and degradation modes, sufficient qualification and durability testing, and manufacturing quality control for the Jbox system (box and connectors) cannot be overestimated since failures of this system account for approximately 18% of 180 fire incidents studied from 1995 to 2012. This study indicates that the jbox with its associated PV connector was the number one cause for a fire, with the second being inverters at 16%. The International Energy Agency’s 2014 report suggests that PV connectors alone may be responsible for up to one-third of PV module fire incidents suggesting that special attention to this component is required. A junction box is an electrical enclosure that protects electrical conductors at the points where they are spliced, tapped and pulled. These enclosures allow electricians to easily access the conductors to perform work when needed while simultaneously keeping the conductors safe from damage and unauthorized access. Sometimes, you’ll hear the term “junction box” used to refer to an electrical fixture box. In the true technical definition of a distribution box, wires should connect only to other wires and raceways. However, in practice, the term is also frequently used to refer to many other electrical box types in which wires connect to a fixture such as a ceiling fan, light switch or wall socket. Sizing a junction box is critical for making sure the junction box functions correctly. In a junction box that’s too small, an electrician may have to bend conductors excessively to fit them fully inside the box, which risks damaging the insulation on the wires. Conductors and other components spaced too closely may also create interference or hazardous conditions. Article 314 of the National Electrical Code contains most of the key regulations that you’ll need to follow when choosing and installing a junction box. These regulations describe in detail the required junction box size, depending on the number and size of conductors and fittings enclosed within the box. You’ll need to calculate both box volume and box fill when determining the appropriate size for a power distribution box. What do these concepts mean? Box volume is the total enclosed volume of the junction box, including any extended space provided by attachments such as domed covers or extension rings. Box fill is the total space occupied by the components that will be contained within the junction box with electric breaker. The box volume should always be greater than or equal to the box fill. To calculate box volume and box fill, you’ll need the tables from NEC 314.16 and knowledge of how to use them. Next, we’ll look at how to use these important tools.
Fecha de Publicación: 21212121-0909-0101
Descripción: Seeing the joy on a loved one’s face when they’re handed a gift is one of the most rewarding moments. If you’re looking to wow your family and friends the minute they receive your gift, then a little creative gift wrapping is just what you need. Luckily, it doesn’t take much time, skill or money—once you have a few gift wrapping ideas. To offer you inspiration for your Christmas, birthday or holiday gifts, we’ve created a collection of over 20 gift wrapping ideas. From simple ribbon techniques to gift-wrapping masterpieces, we have something for everyone. And if you’re still looking for extra special presents for you loved ones, make sure to check out our personalized gifts. 1. Recycle In Style Design your own festive gift wrap from a material you already have: paper shopping bags. Make the project easier by choosing bags from stores that issue holiday patterns. Add colorful ribbon or string to your gift for extra personality. 2. Tea Towel Wrap Choose a gift wrap idea that also doubles as a gift: a tea towel. Bundle a bottle of wine, olive oil, sauce or balsamic vinegar for a present that will go straight to the kitchen. 3. Colorful Hodgepodge Gather your paints, paintbrushes, and sponges. Use white or solid colored paper as your base and sprinkle on all of your favorite colors in any shapes you want. Your gifts will be dressed full of character and personality. 4. Baked Goods Cardcoard Boxes Take empty cardboard candle boxes from rolls of parchment paper or foil. Paint them with festive colors and designs for decorative baked good gift package boxes or other food gift ideas. 5. Holiday Lights Christmas lights aren’t just for hanging on your roof. Cut open brown paper bags to create your wrapping material. Then, draw or paint a set of holiday lights on the paper for a jolly feel. 6. Paper Bows Cut bow shapes out of colored cardboard construction paper. Use an online printable for a cutting guide or make your own stencil. For a tasty twist to this project, fill the centers with a teaspoon of sprinkles. 7. Add A Tag Dress up brown paper gift wrap with fine string or ribbon. Add a gold foil holiday tag for a gift special box wrapping design that looks polished and professional. 8. Washi Tape Weave Washi tape isn’t just for home decor. You can use it to dress up your gift wrapping, too. Create a layered effect by weaving the tape horizontally and vertically in an alternating pattern. 9. 3D Wrapping Wrapping gifts for your kids, grandchildren or nephews? Create your own interactive gift wrap by gluing on their favorite toys like cars, crayons or building blocks. 10. Origami Bows Add a little fun to your gift wrapping project by designing bows out of origami paper. Fold several at a time so you have a stock of bows to use throughout the year. 11. Silver Detailing Wrap your gift in plain brown paper, then use a lustrous silver pen to add details. Draw geometrical shapes, snowflakes or simple lines to accentuate your package. 12. Using box to contain the gift For different kinds of gift, there are watch box, PVC box, food box, perfume box, cosmetic box, etc.
Fecha de Publicación: 21212121-0909-0101