There are two common styles of wood framing: balloon and platform. The main difference between balloon and platform framing is apparent at the floor lines. The balloon wall studs extend from the sill of the foundation all the way to the top plate of the second floor. The platform framed wall, on the other hand, is independent for each floor.

Common Structural Terms

In this section of the course, let's learn about some common terms or phrases that are used in the construction and building industry, particularly related to a residential building. Understanding construction terminology and knowing the purposes of building components and framing members (for example, studs, plates, load-bearing walls) will help a home inspector to do a better home inspection. Even though most building components are not readily accessible and are not readily visible to a home inspector performing a home inspection on an existing (already built house), it's important to know how buildings and homes are built. Sometimes defects can be seen by a home inspector, because the hidden, covered, or inaccessible system or component has a problem.

What's an Arc Flash?

An arc flash occurs when a flashover of electric current leaves its intended path and travels through the air from one conductor to another, or to neutral or ground. It often happens unexpectedly and can be explosive but brief, or it can last seconds and be rather visually spectacular. It can cause a little damage or it can disable a system and require the replacement of equipment. An arc flash of any size is quite dangerous because its path is unpredictable; it will be attracted to the nearest item with the greatest conductivity, such as an unsuspecting rodent or house pet, or a person. An arc flash can cause a serious electrical burn or even fatal electrocution.

All electrical systems require a means of disconnection so that the service can be shut down quickly if any dangerous conditions exist. In this section, we will look at the types of disconnects, and the common problems that need to be reported.

This is often seen by the home inspector as the supply conduit to outside installations, such as air-conditioning compressors.

Wire types for North American wiring practices are defined by standards issued by Underwriters Laboratories, the Canadian Standards Association, the American Society for Testing and Materials, the National Electrical Manufacturers Association and the Insulated Cable Engineers Association.

Knob-and-Tube

Knob-and-tube wiring is so named because of the porcelain fittings used to support and insulate the conductors from the timber components in the home. The knob holds the wire away from rafters and joists, while the tubes are inserted into holes bored though joists and studs to protect the conductor and its rubber insulation.

Circuit Breaker Panels

These are probably the most common type that home inspectors will come across, as they have replaced fuse panels over the last 40 years or so. As we saw for fuse panels, breakers are far from foolproof and require some particular checking.

The purpose of bonding is to ensure the electrical continuity of the fault current path, provide the capacity and ability to conduct safely any fault current likely to be imposed, and to aid in the operation of the over-current protection device.

What Is Grounding?

Generally speaking, the difference between grounding and bonding is: Grounding is a direct connection to the earth to aid in removing damaging transient over-voltages due to lightning. The purpose of bonding is to ensure the electrical continuity of the fault current path, to provide the capacity and ability to conduct safely any fault current likely to be imposed, and to aid in the operation of the over-current protection device. Properly bonding all metal parts within an electrical system helps ensure a low-impedance fault current path.