90 



METHODS OF OOMMUNIOATTON FOR FOREST PROTECTION 



to the protector blocks. Connect the ground wire with the terminal marked G as in 

 Fig. 45. In the case of a grounded line only one of the fuses is used but a short wire 



GffOUNDETD C/ffCU/T 



Through Through 



porce/a/n poroe/a/'n 

 '-tube -fo Tube to 



//ne ground rod 



r~Or? MET/? LUC C/r?CU/T 



Through Through 

 pOrce/ain porce/a'n 

 Tubes /o -fube -fo 

 //ne crround roc/ 



P.-cfector 



&.5 rubber covered 

 braided and weafher 

 proofed copper wire 



#/8 B &S. rubber covered 

 ond braided fw/sfed 

 pair copper wire 

 running from ferm/na/s 

 marked "//ne / * and 

 '//ne 2" /n -fe/ephone 

 se1~ -fo protector sef 

 as shown 



Te/epnone 



Fig. 45 Wiring diagram for telephone station 



should be run on the end of the protector that contains the protector blocks, from the 

 terminal marked G to the terminal at the side of the protector blocks that is not being 

 used. by the main line '(Fig. 45). 



Section 73 "GROUNDS" 



1 GENERAL PRINCIPLES 



Telephones are grounded for two distinct purposes. In both one-wire and two- 

 wire (grounded and metallic) lines the protective devices must always be grounded 

 in order to function properly. One-wire (grounded) lines, however, require to be 

 grounded in order that the return half of the circuit, the earth, may be made avail- 

 able. In grounded lines, therefore, the character of the ground connection not only 

 affects the protection but also affects very seriously the operation of the telephone both 

 for ringing and talking. Poor grounds constitute one of the most common and most 

 annoying sources of trouble in this type of construction. 



While permanently moist earth will generally afford a good ground, yet different 

 soil materials and different geological formations do not always possess the same 

 conducting power. This sometimes makes it necessary to test various places before 



