20 Section 1 Fundamentals Copyright Goodheart-Willcox Co., Inc. shock does not have as much to do with the voltage as with the amount of current. A shock of 10,000 V is no more deadly than that of 120 V. A shock approaching 10 milliamperes (0.01 A) is painful and could cause severe injury. See Figure 2-1. The values and the bodily effects listed in the table are only an average. Con- ditions of body size, skin moisture, amount of food and liquids in the body, surrounding humidity, and clothing all can affect the sever- ity of the shock. You will learn more about volts and amperes later in the text. For now, know that the electricity in most homes is far more than required to electrocute a person. Electrocution is not just any electric shock it is death caused by electric shock. 2.1.2 Burns There are two types of electricity-related burns that can occur. Both are life threatening. The fi rst is called an fi electrical burn, which occurs when electricity passes through the body. Just as wires heat up when too much electricity passes through them, so will the human body. Often, the victim has extensive internal damage with very little external indication of any injury. The second type of electricity-related burn is the result of arc fl ash. fl Arc flash fl is an explosion that takes place when electricity short-circuits through the air or across inadequate insulation. CAUTION Calling C a a l l i g for f Emergency E m e r g g e n c Help H e l p Always A wa know k w w wh wh ere e y yo u u are e w w wo rking rk g and d be able ab to t o describ e sc ri be the he location oc o o n of of the t e work w r k site if you o u have a ve to t t o call ll 911 9 for f emergenc e e me rg n cy help. h el Some w wo rk rk k site s it es ma m ay no n ot ha h h av e e a a street t re t address a yet. If I f you y ou call l l 911 1 from om m a cellul c u la r phone, ph the dis- p pa pa t tc h c ce nte t er ma m ay ay be b e able b le to o t tr ace your call to d de termine te in y yo yo ur r general n al location. However, this th inform i nf r m ma tio ti on may m y not n be specific enough to o locate l at at e you yo quickly. qu kl Always learn the street a ad dre dr r es s s of th t he work w site, if available. If not, know kn kn w the e nearest ea existing address or cross streets t re s and n d be prepared to describe your exact ac t loc o ca tion. The temperatures during an arc fl ash are high fl enough to melt metal. An arc fl ash projects fl melted metal outward, injuring any unpro- tected workers in the area. The best way to pre- vent an arc fl ash is to de-energize equipment fl before working on it. If this is not possible, be sure to wear the appropriate clothing and eye protection. Immediate treatment for a burn involves removing the source of the heat and calling for medical help. Burns caused by electric shock or arc fl ash are usually too severe to be treated by fl anyone other than a doctor or paramedic. While waiting for help to arrive, cool the burn with sterile gauze soaked in cool (not cold) water. Do not apply ice to a burn, and never put but- ter, grease, or medical ointments on the burn. Be prepared to treat the person for shock. 2.1.3 Eye Injury An eye injury can be one of the most devastating wounds a person can receive, but is also one of the easiest to prevent. Always wear your safety glasses whenever there is the slightest chance of an object being projected. You should also wear safety glasses when working in a position that causes you to look overhead. Dust and debris often fall from upper areas during construction. If any of this material falls into your eye, you may suffer an injury ranging from eye irritation Goodheart-Willcox Publisher Figure 2-1. Even very small amounts of current passing through the body can be lethal. Average Effects of Electric Current on the Body Amount of Current Effects E ff on the Body ff ff 0.001 A (1 mA) Felt slightly as a tingle 0.001 A to o 0.01 0 0 A (1 mA m A t to 10 mA) Would probably cause muscles to contract and prevent victim from releasing the object 0.01 A to 0.1 A (10 mA to 100 mA) Fatal after several seconds duratio a ti on 0.1 A or more (100 mA or more) Almost o st always a fatal