A slab-on-grade foundation is a type of foundation consisting of a structural concrete slab poured onto the ground, but usually, there is a layer of gravel and a vapor retarder between the ground and concrete. View illustration of a slab-on-grade installation. No accessible space exists in slab-on-grade construction. Slab-on-grade foundations are popular in areas where there is a high water table. For example, there are very few full basements in Southern Florida. In general terms, a slab-on-grade foundation is poured on the grade or ground. complements of InterNachi @ www.nachi.org

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.

Many people use the name Romex® when referring to type-NM cable. Romex® is a trademarked name that has come into common usage for referring to plastic-covered wires, but type-NM just means "non-metallic" and also applies to other cable styles.

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.

Many roof problems are caused by issues with the framing and sheathing. In this section, we will focus on the defects that may be viewed from the exterior of the property. This is one of those cases where standing back and taking a good, hard look is better than getting "up close and personal" with the roof.