Electrical service is the energy supplied by an electric utility company. This electricity travels to the house via large wires that connect to a main panelboard, also known as a breaker box.
These wires can be underground or overhead. Inspectors examine the lateral service wires and make sure there are proper clearances.
Electrical Wiring
Electrical wiring is the cabling that carries electric current between points in a building or structure. Electrical wiring is subject to strict safety rules and standards for design, installation, and operation.
In a residential house, electrical wires are typically encased in code-recognized insulated plastic cable. They are colored to indicate the circuits they carry. Hot wires are usually black or red, and neutral wires are either white or gray. Grounding wires are either green or blue with a yellow stripe, and they may also be bare copper.
The main electrical wiring in your home connects to the meter socket, a device that measures your electricity usage. It is then fed to the service panel, which breaks up the incoming feed into individual circuits that power switches and outlets throughout your home. Often, homeowners are able to replace the meter base and weather head, as well as the service panel, without changing the wiring. This can save you time and money.
Service Panels
Electricity enters your home through the utility wires and the service panel, which is a metal cabinet that contains “hot” and “neutral” bus bars (relatively large metal strips designed to carry substantial amounts of electrical current while dissipating heat) and circuit breakers or fuses. Breaker switches and fuses protect your wiring, outlets, and appliances from overcurrent that can cause fires.
If your home is older, it may still have fuse boxes. If so, the fuses will need to be replaced with screw-in fuses or cartridge fuses that plug into place. Newer homes have circuit breaker panels.
If a breaker switch trips, it is probably because of an overload of your appliances or overheated electrical wiring, which is dangerous and needs to be fixed right away. You should always be careful when working on an open electric service panel, even if the main switch is turned off, as exposed bus bars can still conduct deadly electrical currents.
Meters
Electricity meters are usually placed where the power lines enter a building or structure. They can be located on the electric pole serving the property or in a cabinet or other outside meter box attached to the service entrance line. They are often bi-directional cumulative or interval meters.
Electric utilities will require that the meter is read at least once per year by a representative of their company, or by the customer. This allows the electricity company to verify that the customer is providing accurate meter readings.
Inspectors should always look for evidence of tampering to the meter. Tampering with electrical meters is illegal and extremely dangerous. Meters may also be protected with locks that must be kept secure, and many are sealed. Electricity meters can measure kilowatt hours, demand, volt-amperes and other quantities related to the flow of electricity. Many modern meters are also capable of detecting and logging anomalies such as leaking water, magnetic field interference, extra clock setting, glued buttons, reflected load currents, ambient DC currents and other conditions.
Switches
The switches in a breaker panel control the electricity that reaches the different parts of your house. It’s a good idea to know where they all are in your panel so that you can shut off the right circuits when doing an electrical repair or cleaning. If you’re lucky, the switches will be labeled so that you can figure out which ones are for what rooms and appliances.
A switch’s basic function is to interrupt the flow of electric current through a circuit by changing the properties of part of the conducting material in the circuit that’s being switched off. The change in conductor properties can be caused by an opening between contacts or by the creation of an air gap that has different electric properties from the conducting material and thus stops current flow across it. The switching operation might involve physical movement, but some switches don’t have that capability. The power rating of a switch shows how much electric current it’s rated to handle before it starts experiencing physical damage.
