INSTALLATION OF ARC LAMPS 



[CH. XIII 



The wire is fixed firmly under the set screw, and if the current is 

 to be large, 30 amperes and more, the wire should be soldered to its 

 connection after the screw is firmly set down. 



699. Connecting the conductors to the switch. This is done 

 exactly as for the attachment cap. 



In case direct current is used it is important to know which is the 

 positive and which the negative wire. This should be determined 

 before clamping the wire to the switch. The best method is by the 



FIG. 269. SEPARABLE ATTACHMENTS, POLARIZED (A) AND NON-POLARIZED 



(BC). 



(Cuts loaned by H. Hubbell. Inc.). 



The attachments A and B are for the ordinary bulb socket. 



A is polarized so that the same polarity of the wires is insured, for the connec- 

 tion cannot be reversed. 



B is non-polarized and the polarity may be reversed every time the connec- 

 tion is made. 



C is for receiving an incandescent lamp ; connection is made with the supply 

 by inserting the prongs into an attachment plug which has been screwed into a 

 lamp socket. 



use of the arc lamp ( 702), after the arc lamp and rheostat have 

 been properly connected. 



700. Wiring the arc lamp, including the rheostat or other 

 balancing device. From one pole of the switch (fig. 270), a wire 

 of the proper size and insulation is carried directly to the 

 negative binding post of the lamp, i. e., to the post for the lower 

 carbon. From the other pole of the switch a suitable wire is 

 carried to one binding post of the rheostat. From the other bind- 



