Electrical service is the system that brings power to switches, outlets and appliances throughout a home or building. This system is referred to as the main electrical service, or simply “mains electricity”.
Residential electric services usually include a main panel which serves to connect the external wires to the internal circuits of a home. The main panel is also referred to as a breaker box or fuse box. It’s often found in a garage, basement or utility area of a home. In some homes, the main panel may be located inside a cabinet mounted to the wall. Commercial properties usually require a large main service panel with a capacity that can handle multiple loads.
A main electrical service can be provided through overhead or underground wires. Overhead lines are commonly used in older properties, while newer developments typically use underground lines (also known as a lateral).
When inspecting an electrical system, it’s important to note whether the service drop is overhead or underground. If the lines are overhead, there are specific clearances that need to be maintained to ensure safety. For example, the height and location of trees must be carefully monitored to prevent the growth of limbs and debris into the line. This could cause damage or even downed lines, which would result in the loss of power to a structure.
Once the service wires reach the main panel, they are connected to individual branch circuits which run throughout a house to power switches, outlets and appliances. These are usually 120-volt circuits with a combined amperage of up to 200 amps. This is not a large amount of power, but it’s enough to accommodate most household demands.
It’s very important that homeowners never attempt to make any repairs, maintenance or modifications on their own to the service wires. Doing so could be very dangerous, resulting in an electrocution or fire. It’s also recommended that homeowners call a licensed electrician when adding anything to an existing electrical system, such as adding additional breakers or wiring an entire room for remodeling.
During a home inspection, it’s important to observe the condition of the electrical service and branch circuits. A professional home inspector will note any problems with the system as well as provide the customer with a written report.
When observing the service wires, it’s also important to count the number of wires at the top of the pole. If there are two wires, it indicates a single phase system; if three wires are at the top of the pole, it’s likely a 3-phase system. Inspectors should also look at the meter and panel to ensure that they match. Lastly, the inspector should also note whether there is a grounding rod connected to the electrical service. This will help to protect against accidental contact with the service wires and reduce the risk of electrocution during a fault or overload. In addition, the grounding wire acts as a path for current to return to its source, which is the electric meter.