400 Electrical Systems Using testing and measurement, you can identify the faulty component in the circuit and replace it. Th is approach is far more effi cient and aff ordable than guessing and swap- ping out part after part until the problem is resolved. 21.1 ELECTRICAL SAFETY Safety is the most important part of testing and measure- ment. Be mindful of all safety procedures when making measurements. Anyone who makes their living working with electricity must develop a healthy respect for the potential dangers involved in dealing with live circuits. 21.1.1 Physical Condition Your physical condition can lead to potentially unsafe and dangerous actions. Always be well rested when at work. If you are tired due to lack of sleep, your mind can be “foggy” and your refl exes slowed. Th is can lead to a poor decision or delayed action, resulting in a dangerous situation and potential injury. Never work if your body is experiencing the eff ects of alcohol or drugs. Alcohol and drugs greatly reduce mental and physical abilities, which can lead to unsafe practices. In addition, arriving to work under the infl u- ence of alcohol or drugs is cause for immediate dismissal at many companies. Illness can also lead to unsafe practices. Sickness may reduce mental and physical abilities, not unlike drugs or alcohol. If you do not feel you can do your work safely, call in sick. Mental stress can also result in unsafe practices. Th e pressure of needing to get a vital piece of equipment back in operation or the time constraints of completing the job can cause stress. Even experienced technicians can make unchar- acteristic mistakes when trying to work too quickly. Th ese mistakes may result in fatal consequences. Never ignore safe practices in order to complete a job more quickly. 21.1.2 Electrical Testing Safety When preparing to perform electrical tests and measure- ments, begin by wearing the proper personal protective equipment (PPE). See Figure 21-2. Your company or school will have policies regarding what PPE you should use based on the tests being performed, the equipment being tested, and the environment where the test is being conducted. OSHA also has guidelines about what PPE is appropriate. Refer to Chapter 2, Industrial Safety and OSHA, for additional information about PPE. Reproduced with permission, Fluke Corporation Figure 21-1. Electrical measurements provide information about how a system or equipment is operating. These measurements can be analyzed as part of the troubleshooting process. Reproduced with permission, Fluke Corporation Figure 21-2. Always wear the appropriate personal protective equipment (PPE). This industrial maintenance technician is wearing hearing protection, safety glasses, and a hard hat while taking temperature measurements. Copyright Goodheart-Willcox Co., Inc.