Electrical Wiring Installation Burke VA
Virginia Beach, VA
Harrisonburg , VA
Home Lighting Information
Have you ever thought about building an outdoor kitchen, adding a pool or hot tub, running decorative lights along your driveway or adding electricity to a detached garage? Many homeowners are afraid to work with electrical wiring and prefer to hire an electrician. While we certainly don't want to minimize the risks of working with electricity, this is one area where a knowledgeable homeowner can save a lot of money, if he or she is willing to learn the basics. Most municipalities allow the homeowner to install electric wiring in and around their house (with the exception of the main power line - see sidebar on page 50), as long as the electrical code official inspects it. This article will provide you with a basic understanding of wiring outside the house. Most local governments enforce the National Electrical Code, but you should check with your local official to make sure. You may also need a permit for adding to your current electrical system. And, if possible, get the finished job inspected so that your insurance company will cover damage in case your new circuit causes a fire. As with any project, it is important to plan your work first. What do you want as a finished product? If you are bringing electricity to a detached garage or shed, what kind of lighting and power requirements do you need? Are you looking for an outdoor workshop with power tools? Do you want any appliances? Do you need electric service for heating? If you are building an outdoor kitchen, what kind of appliances will you desire? How much lighting do you want? What are the power requirements of pool pump motors or hot-tub pumps? Electricity is a resource that is fed by wires. Each appliance, light, pump or tool requires a certain amount of electricity to operate, which when added together, gives a total load for the job. The type of wiring and the components of service (i.e., electric panel, circuit breakers, etc.) are all based on the total electric service required. Electricians follow the NEC when planning circuits. It's a fairly complex guide, so you may want to consult either an electrician or your local electrical code official. Try to anticipate future needs for each circuit. While this may seem somewhat daunting, a good plan and diagram will clear up the confusion and make for an orderly project. Start With a Plan First you need to diagram where you want to locate receptacles, switches, lighting fixtures, pump and sprinkler motors, trenches, and cable runs. Your plan should also show the location of major elements, like pools or ponds, outbuildings, patios, and yard equipment. It should include other important items, especially known hazards, such as large trees, boulders and rock outcroppings; and underground hazards, like pipes, cables and septic systems. Your plan needs to account for the power load of all anticipated uses. Check the labels on appliances, tools and motors for the total number of watts or volt-amps needed to run the item. For some jobs, like wiring a backyard workshop, it would probably be a good idea to plan on a separate electric subpanel or breaker box to provide enough circuits for all of the power needs. It is generally better to have too much power than too little, although you don't want to overestimate grossly. According to Warren Goodrich of www.homewiringandmore.com, "Most people overwire their detached garage and spend money on a service 10 times larger than is needed, then don't have the money to install the equipment they want. Don't underrate, but also don't overrate your detached-garage power supply." In addition to the load, you also need to factor in distance, since this will have a direct effect on the size of the cable required. Electrical resistance in the cable causes a voltage drop proportional to current. The NEC recommends limiting voltage drop to 2 percent.The table on page 52 shows the maximum one-way cable length versus cable size and rated amp capacity for a 2 percent voltage drop in 120-volt and 240-volt circuits. For example, for a 132-foot, 120-volt, 30-amp run, you need to use a No. 4 cable. Another critical factor of your plan is the route for the cable. You need to make sure that your route will avoid aboveground and underground obstructions. The NEC requires that underground cable be buried at least 18 inches beneath the surface and 24 inches below a drive or walkway; however, you need to check with your electrical code official for the standards in your area. If you excavate randomly, you may unwittingly cut into a sewer or water pipe, or telephone, cable TV, or electrical power line. In most areas, you are required by law to inform your utility company before you do any digging. They will come to your property and mark the location of any underground utility lines that exist where you plan to dig. Call 888-DIG-SAFE (344-7233), which is a free service that may save your life. Also, if you are on a septic system, you need to check whether the system is near your planned cable route. You also need to check your soil and subsurface conditions - if you have a high water table, bedrock that is at or near the surface, or soil containing a lot of rocks, you may not be able to dig a trench. Once you have identified all of the hazards, draw a route diagram that will avoid these obstacles. Be aware that ground-fault circuit interrupter (GFCI) protection is required for outdoor wiring. A ground fault happens whenever electricity escapes the confines of the wiring in an appliance, light fixture or power tool, and takes a shortcut to the ground. When that shortcut is through a human, the results can be deadly. There are two kinds of GFCI protective devices: a receptacle-style and a breaker-style. Both devices are designed to be installed at the beginning of the circuit to be protected. You only need to install a GFCI device on the first receptacle of each circuit. Alternatively, you can use a GFCI circuit breaker in the main line going outside. If you are using a circuit that is rated at 220 volts or over 30 amps, or a circuit that is hard-wired without a receptacle, then no GFCI protection is required. Lastly, check with your local building department to see if you need a permit for the work. Dig In Once your plan is approved, you can dig your trench using a shovel, backhoe, trencher or any other suitable equipment. Keep your trenches as straight, short and narrow as possible to reduce expenses and effort. Drive stakes along the cable route of your plan, beginning directly below where your cable will be exiting the house. Run mason's string between the stakes to help guide you as you are excavating. Remove the upper layer of sod and store it on a sheet of plastic so the sod can be replaced when the work is done. Use the same procedure to capture the dirt from the trench. Select and mark the location on the inside of your house where you want the cable to leave. This point should not be far from your service panel, as the length of the interior run must be included in your calculations for proper cable sizing. The exit through the wall should be at least three inches from the nearest joist, sill plate and subflooring to allow sufficient clearance for a junction box. Drill a hole slightly larger in diameter than your conduit, and mount a junction box in the interior, over the hole. If your exterior walls are masonry, use a hammer drill to make an access hole. Try not to make your exit on the top course of block on a concrete-block wall, since this is often grouted solid to secure the anchors that hold the sill plate of the house in place. Alternatively, consider exiting through the rim joist above the foundation. After drilling the access hole, mount a junction box over the hole on the inside and an LB fitting on the outside. Run a short length of rigid-metal conduit (a "nipple") through the wall to link the interior junction box to the LB fitting. Identify the appropriate circuit breaker in your main service panel and make sure that it is off! Run the cable from the main box to the new junction box. Pull the supply cable into the box, and secure it using a cable clamp. Install the Conduit Any outdoor cable that is run underground must be protected in rigid conduit where it enters or emerges from the trench. Run a length of conduit from the LB fitting/junction box down into your trench 12 inches below grade. Then attach a conduit sweep bend to the end of the straight section of conduit, using a conduit compression connector. The sweep bend allows the wire to move from vertical to horizontal without putting too much stress on the cable. Anchor the conduit to the house or foundation wall, using mounting straps, self-tapping screws or masonry anchors. You will most likely use underground feed (UF) cable. You can also use stranded wire with a Type THWN, THW or TW rating, completely encased in conduit, depending on local codes and overall cost. One advantage of conduit with stranded wire is that you can replace the wire in the future without having to dig up the yard. If you use UF cable, you need to feed the end of the UF cable into the sweep bend and up into the LB fitting/junction box. Splice the UF and power feeder cables together inside junction box. Extend the UF cable along the bottom of your trench to the point where you need the service, and follow the same procedure for connecting it to the power feed on the receiving end of the cable. Wrap electrical tape around the point where the UF cable enters the sweep bend to ensure that there is no chafing of the UF cable. Allow a few inches of slack as the cable enters the conduit to prevent unnecessary stress on the cable. Do not pull the cable tight, as this may result in damage or breakage as the soil shifts against the cable. If you use conduit for the entire length, you need to feed the stranded wire through the conduit until you reach the receiving end. Final Connections Once you have run the cable to the other end of the trench, you need to connect the UF cable through another sweep bend and LB fitting/junction box. If it is an inside application, like a detached garage or workshop; or a fixed installation, such as a pool or hot tub, there should be a junction box to which you can attach a conduit directly. Where you are just installing lighting or just one electrical appliance, you can connect directly into the fixture. For most large applications, you will need to connect to either a junction box or a subpanel. From there, the wiring is the same as for any other interior wiring. After all of your wiring is connected, you should turn on the circuit breaker in the main box and test each receptacle with a circuit tester to make sure the connections are properly wired. Do not fill the trench or enclose any wiring in walls until you have had your electrical inspection, if required. Once your system has been inspected and tested, you can shovel the excavated soil back into the cable trench, being careful that no rocks are close to or touching the cable. You should also replace the sod and gently tamp it back into place. Do not plant anything with deep roots directly over the cable trench. Bringing electric service to the outside of your house can open up a number of possibilities to extend the enjoyment of your property. If you are careful and follow all code requirements, you can save a lot of money. Most importantly, you will have the satisfaction that comes from doing the job yourself, especially as you relax around your new pool, work in your new outdoor workshop or luxuriate in the warmth of your hot tub. For More Information: www.homewiringandmore.com The NECdigest (part of the National Fire Protection Association) www.nfpa.org/nec/nechome.asp Barry Chalofsky is an environmental land planner and author of The Home and Land Buyer's Guide to the Environment. Visit his website at www.erols.com/profed.