From a wire table in the National Electrical Code (1971), page 487, find the following: 



Size No. 1 AWG (American Wire Gauge) is 83,690 circular-mils (too small) 



Size No. of 1/0 is 211,600 circular-mils (too large) 



Since there is no size between these two, use the wire closest to the requirement, the 83,690 

 circular-mils wire, and tolerate the slight difference in drop. In using the No. 1 wire, note 

 that the voltage drop is about the 3 percent required and is close enough for practical 

 purposes: 



.r , , 21.6 X 300 X 50 „ „„ , 



Volts drop = ^„ ^^^ . ; — = 3.87 volts 



83,690 circular-mils 



3.87 volts 

 Percent drop = — — — ; — X 100 = 3.2 percent 

 ^ 120 volts ^ 



Outlets should be ampere-rated— 20 amperes for to 20 amperes; 30 amperes for to 30 

 amperes; and 50 amperes, for to 50 amperes. In addition, outlets must contain a separate 

 grounding pole for each white-green grounding conductor. 



Circuit breakers (used as circuit protective devices instead of fuses) provide quick 

 restoration of service after an outage. Maximum circuit loads should not exceed 75 to 80 

 percent of the breaker-trip rating to compensate for higher than normal ambient 

 temperature conditions. 



Experience has indicated that maximum demand on circuits is between 20 and 50 

 percent of the connected load outlets. However, each case should be individually estimated. 



Lighting circuits are rated 100 percent of installed lamp-load in watts plus 25 percent, 

 and demand is 100 percent. For best results, lighting facilities should not be supplied from 

 outlet receptacle circuits. 



AU equipment must be weatherproof or raintight and safely installed, and not be a 

 hazard either electrically or mechanically to persons, craft, or navigation. 



Dock lighting methods vary considerably throughout the United States. Many older 

 marinas were illuminated with a few floodlights around the basin perimeter. This method of 

 lighting proved inadequate, as light failed to reach some of the outermost slips and the 

 floodlights caused excessive glare, both directly and by water reflection (Fig. 106). Most 

 floodlights have been replaced with a system of smaller Ughts set between 8 to 12 feet over 

 the main walks of the marina at frequent intervals (Fig. 107). Complaints about glare have 

 led to the small, well-shielded lights set at about 30 inches above deck level that are now 

 prescribed by some harbor administration agencies (Fig. 108). However, one marina 



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