Watt - Volts x Amps = Watts. It is a “unit of power,” and can also be described as a measure of the amount of energy produced. A flow of 3 amps from a typical house 120-volt receptacle outlet equals 360 watts. Ohm - A “unit of electrical resistance” to current flow. The heating elements in a toaster, for example, have high electrical resistance that creates heat.
Short Circuit - An unintended connection between parts of a circuit. A short circuit typically, but not always, trips a circuit breaker, and a short at a receptacle outlet leaves black burn marks on the cover plate from the surge of electricity.
Electrical Components
Bus - A metal strip inside a panel that serves as a common connection for multiple circuit wires. A panel typically has both a neutral and ground bus, or a single bus for both.
Bus Bar - A metal strip inside a panel used to connect circuit breakers. Cable - A cluster of wires encased in a flexible sheathing. Initials identify the type of cable, such as NM (Non-Metallic) or UF (Underground Feeder).
Conductors - There are three types:
-
1)Ungrounded Conductors - The “hot”wires, usually black or red.
-
2)Grounded Conductors - The “neutral” wires, usually white.
-
3)Grounding Conductors - The “ground” wires, usually green or bare wires.
Dead Front - The plate the covers the front of an electric panel, with openings for the circuit breakers to protrude, enabling them them to be safety operated while protecting the live electrical connections behind it from contract. Called a “dead” front because it is isolated from any voltage in the panel.
Disconnect - A device that cuts off the current to an appliance or circuit. It can be a switch, circuit breaker, or cord that can be unplugged from a receptacle.
Electric Panel - The cabinet with components that distribute electricity around the home. The first panel after the electric meter is called the service panel and the ones after that are subpanels. “Main panel” is a slang term sometimes used to describe the service panel.
Grounding Electrode - A conductive object makes a connection to earth from the electrical system. It is typically a ground rod, but can also be underground metal piping or the reinforcing steel in a foundation footing.
Knockout - Perforated circular tabs in the walls of an electric panel that can be easily broken loose to create a hole for bringing wiring into panel.
Luminaire - A term that has replaced what was formerly called a “light fixture” in building codes.
Receptacle Outlet - A connection device that receives a plug and cord. A receptacle that have two plugs connected to it is a duplex receptacle.
Service Drop - The overhead wires that run from the utility transformer to the house.
Service Lateral - Underground wires running from theutility transformer to the house.
Service Mast - The pipe that extends above the roof to which the service drop wires are connected. It is topped with a weatherhead to keep water out.
Terminal - A lug or screws that secure wires to breakers, bus bars, and neutral/ground bus.
Twistout - Perforated metal plate in a panel dead front that is removed (twisted out) to allow a circuit breaker handle to protrude through the dead front.
Blog Posts About Typical Electrical Defects
-
•What are the most common homeowner wiring mistakes?
-
•Can old electrical wiring go bad inside a wall?
-
•What are the most common problems with electrical outlets?
-
•My circuit breaker won’t reset. What’s wrong?
-
•What is reversed polarity at an outlet/receptacle? Why is it dangerous?
-
•Why is a fuse box an insurance problem for homebuyers?
-
•Why is undersize wiring in a house dangerous?
-
•What is an open electrical splice?
While we hope you find this series of articles about home inspection helpful, they should not be considered an alternative to an actual home inspection by a local inspector. Also, construction standards vary in different parts of the country and it is possible that important issues related to your area may not be covered here.
© McGarry and Madsen Inspection
