28 Section 1 Preparing to Build otherwise repaired. If the cord is damaged, it can be replaced. Safety Note There are a number of general safety rules that apply to power equipment. In addition, special safety rules must be observed in the operation of each individual tool or machine. Those that apply directly to the power tools commonly used for carpentry are listed in Chapter 5, Power Tools. Study the rules and follow them carefully. 2.9 Electrical Power Electrical power is almost always essential on a construction site. Its source may be an electrical generator or a power pole, Figure 2-12. Safe use of this power is important—even a small amount of electrical current is capable of causing serious injury or death. On the jobsite, electrical power travels through power cords. From its source, the cur- rent travels through one conductor, known as the hot conductor, to the tool. It then returns to the source through a second conductor, known as the neutral conductor. Insulation on hot con- ductors is always either red or black. Insulation on neutral conductors is always white. A third conductor in the power cord is known as the ground conductor, or ground, and usually has green insulation. Its purpose is to safely carry away the current from accidental grounding. Chapter 5, Power Tools, explains this in more detail. Moisture can turn many materials, including soil, into conductors of electrical current. A worker can become a part of the current-conducting loop Goodheart-Willcox Publisher Figure 2-12. Power sources. A—A typical building site power pole. B—When there is no electrical utility avail- able, portable diesel- or gasoline-powered generators are used. A B Copyright Goodheart-Willcox Co., Inc.