TRANSMISSION OF ELECTRICAL ENERGY 211 



energy used at any one time. Kilowatt-hours mean the 

 amount of energy used over any given period of time. 



To illustrate : Assume a motor of a different size makes an imme- 

 diate demand on the power plant of 1 kw. If the motor continues 

 running for two hours, the amount of electrical energy consumed is: 



1X2=2 kw.-hrs. 

 That is, the motor demands 1 kw. and the consumption is 2 kw.-hrs. 



259. Injuries in Electrical Work. Injury in electrical 

 work is usually caused by direct contact with a live conductor 

 and may consist of either a shock, burns, or both. 



When the electric current enters the body, it causes more 

 or less complete paralysis of the nervous system; this in turn 

 causes the heart and lungs to cease functioning. The degree 

 of the shock depends upon certain conditions. For example, 

 if an electric circuit is completed by making a contact with 

 the body at the shoulder and hand of the same arm, the 

 current will pass through the arm and not reach the heart 

 and lungs. On the other hand, if the circuit is completed 

 from hand to hand the current will pass through the body 

 near the heart and lungs and may be sufficient to cause death. 

 Sometimes the shock may not kill but stun the person to such 

 a point as to stop his breathing. This is due to the fact that 

 the skin of the body, unless wet, offers high resistance to 

 the current and the conductor makes only a short and in- 

 complete contact with the body. A person can be released 

 from a contact with a live conductor only by means of a 

 piece of dry, non-conducting material, such as a piece of 

 wood, a coat, rope, or hose. If possible, the switch should be 

 turned off or the wire should be cut by means of rubber 

 protected shears. 



