Electrical Systems in the Home

Real Estate

Today’s video blog is meant to provide some very basic knowledge about the electrical system in the home. Hopefully this will help you identify the age and potential need for repair or replacement of electrical systems when touring homes, you are considering for purchase.  CLICK HERE TO WATCH THE VIDEO

The electric service panel is the connection between the external wires coming from the street and the internal wires of your home's electric system. One way to find your electrical service panel is to first go outside and locate the service drop where it connects to your home. The service panel should be directly below inside the home. For buried power lines, usually the line will start at the street and connect to the home near the front or side of the home.
A typical main panel receives three incoming electrical service wires and routes smaller wires to subpanels and circuits throughout the house. Behind the main panel's circuit breakers, power is delivered through charged bus bars that the circuit breakers clip onto.

Residential electrical service panels typically provide 100, 150, or 200, amps of power to a home. Power comes into the house from a service drop, connects to the service lugs within the service panel, and is split into separate circuits which lead to the outlets throughout the home. The service drop will vary in diameter getting larger with more amps being serviced.
If you see an older screw in type fuse panel in the home you are considering, it is a good idea to plan on having that replaced by a more modern circuit breaker panel. The cost to replace the panel will vary depending on the contractor, accessibility, and other factors but a basic rule of thumb for panel replacement is approximately $10 per amp. So, a 200-amp panel should cost about $2,000.00 to have installed by a licensed electrician.
The service drop wire can become deteriorated by the sunlight and age. They can become frayed or lose their outer covering completely over time making an unsafe condition requiring the replacement of that service drop wire. The cost of this can add several hundred dollars to the bill depending on how long the service drop wire is.

Other things to look for:
If you see one of these types of panels that have been labeled a safety risk, you may want to replace it as well:

Federal Pacific Electric Electrical Panel: The U.S. Consumer Product Safety Commission classified this panel as a safety defect advising that a new electrical panel replace it. These panels were installed in homes between 1950 and 1980, have design and manufacturing defects that cause fires or shocks.

Zinsco Electrical Panel: These panels were taken off the market in the1970s. They have a defective design that allows power to flow even when the breakers are switched off. Breaker switches also melt, rendering them useless. Zinsco electrical panels are fire and shock hazard and should be replaced.

Pushmatic Electrical Panel: These breaker boxes house weak breaker switches that get harder to reset over time. Pushmatic panels also do not have a main breaker switch to stop power into the panel.

Panel doors that can’t be opened fully due to obstructions. Garage door rails, framing, etc.
Open circuit breaker spaces where the breaker was removed, and the opening not capped.
Low Voltage Relay Type Push Button Light Switches
Water getting into panel causing rust and corrosion due to unsealed entry holes.
Older deteriorated overhead wires with three separate wires instead of the more updated tri-plex lines that combine the three wires into one.
Loose service cleats where the overhead lines connect to the house and service drop wire.
Two Pronged Ungrounded Outlets

It is dangerous to work on an open electrical service panel with both the door and the protective front cover removed. It is always recommended that a licensed electrical contractor perform any work requiring the front cover to be removed.