Your Home Electrical System. In many older residential areas, and practically all rural locations, the electrical supply is delivered to the property via overhead conductors strung on telegraph poles. The high-voltage lines connect directly to the property through a transformer delivering main power.
Most residential buildings are supplied with 120/240-volt services. This means that the cable assembly is made up of two un-grounded (live or hot) conductors each supplying 120 volts, and one neutral or grounded conductor acting as the return.
The masthead, or gooseneck, as it is sometimes called, is at the top of the mast itself. Its purpose is twofold: first, to act as a rain cap to stop moisture from entering the conduit; and, second, to provide the bushings to prevent the individual conductors from being damaged by rubbing against the metal components. The masthead should be undamaged and securely fastened to the service mast.
Type-UF cable is rated for direct burial, and has outer sheathing that is resistant to moisture and damage from soil. This type of cable must be buried to a depth of 18 to 24 inches (depending on the location, as described in section/table 300.5 of the NEC) and, if embedded in rocky ground, must be installed in a manner that will not damage the cable. This cable still needs to rise in a conduit to prevent mechanical damage before it enters the building. The visible conduit should be made of either galvanized steel or gray plastic, rated for the purpose.
Electric charge is a property of certain subatomic particles, which gives rise to and interacts with the electromagnetic force, one of the four fundamental forces of nature. Charge originates in the atom, in which its most familiar carriers are the electron and proton. It is a conserved quantity, that is, the net charge within an isolated system will always remain constant regardless of any changes taking place within that system. Within the system, charge may be transferred between bodies, either by direct contact, or by passing along a conducting material, such as a wire. The informal term static electricity refers to the net presence (or ‘imbalance’) of charge on a body, usually caused when dissimilar materials are rubbed together, transferring charge from one to the other.
The main circuit breaker, usually located inside the main panel at the top, shuts off all of the electricity to the house. In a dire emergency, this is the one to turn off. Otherwise, shut off only the breaker that serves the problem circuit-that way, other parts of your house will continue to have lights and power. The main circuit breaker does not shut off the wires that run from the main panel breakers to the electric meter-these are always hot.
A typical home has several circuits to deliver electricity to different areas of the property, as shown in the illustration below. All of these so-called branch circuits originate at a service distribution panel, which has two hot bus bars and one neutral bus bar. Depending on the amount of electricity a given circuit needs to deliver, it may attach to only one hot bus bar and the neutral bus bar or to both hot bus bars. For example, a circuit that delivers 120 volts connects to one hot bus bar and the neutral bus bar, while a circuit that delivers 240 volts connects to both hot bus bars.
Many people use the term “Romex” when referring to type-NM cable. Romex is a trademark name that has come into common usage for plastic-covered wires, but type-NM just means “non-metallic,” and also applies to other cable styles. The earliest NM cables were, in fact, rubber-insulated copper conductors bound together as an assembly, with a woven-cloth sheathing. Originally approved by the NEC in 1928 as replacement for knob-and-tube wiring, it became the most common residential wiring used from the late 1940s, up to the introduction of modern thermoplastic (Romex) type wiring of the early 1960s. Prior to 1985, standard NM was rated for 60-degree applications, which was increased to 90 degrees and is now marked NM-B.
The Barrie Home Inspector checks your electrical panel and home circuits during your home inspection. He can identify illegal connections or poorly installed wiring. With all the Do-It-Yourself work being done in homes today, it is a good investment to have your home inspected by a professional prior to purchasing. Some sellers hide defective workmanship and the fact that work was done without a permit and hope that the buyer does not ask or notice the deficiencies. Be a smart consumer protect yourself with a Professional Home Inspection.