. Electrical news and engineering. rd slate and wdien theswitch unit is inserted the blades of the switch make directcontact between the l)us bars and the fuse terminals. Theseswitclies are all and may be readily replacedby a switch of larger or smaller capacity, should the occa-sion arise. Nothing is mountc<l on the front of the switch-lioard except the switch handles and a card holder to indi-cate the circuits controlled l)y the switch. Since the switchhandle is not connected with any surrcnt carryiing part, thefront of the lioard is absolutely safe. At the hack of theboa
. Electrical news and engineering. rd slate and wdien theswitch unit is inserted the blades of the switch make directcontact between the l)us bars and the fuse terminals. Theseswitclies are all and may be readily replacedby a switch of larger or smaller capacity, should the occa-sion arise. Nothing is mountc<l on the front of the switch-lioard except the switch handles and a card holder to indi-cate the circuits controlled l)y the switch. Since the switchhandle is not connected with any surrcnt carryiing part, thefront of the lioard is absolutely safe. At the hack of theboard no live parts are exposed, as everything is totally en-closed. If all the switches arc closed so that the fuses arealive, all the fuse doors are automatically locked. Should itbe necessary to renew a fuse, the switdi atTected is thrownoff and then the switch door can be opened, as shown inFig. 1. .Ml the current carrying parts are now dead, however. OOOR POR FUS6AWO TERMINAL SWITCH MAK&5DIRfCT CONTACTWITH BUSBARSWHEN SWITCH. Fig. the fuses can be removed without danger. It also impossible for one man to close a switch when another isrenewin,g the fuses, for the door must be closed tightly lie-fore the switch can be thrown on and the fuses energized. The switch itself consists (when single-pole) of a mov-able arm. When closed, one end of the movable arm ispressed against the bus bar. and the other end against thefuse terminal, thus bridging the gap between them. Whenthe switch is open, both ends of the arm are clear of theirrespective contacts. The switch is. therefore, double-break,and wdien open, leaves the entire fuse box dead. The switcharm is laminated, and makes contact under considerablepressure. It opens with a quick snap, no matter how slowlythe operating handle on tlie front of the panel may be \11 parts wliicli are not necessary to reach in normal opera-tion are protected by covers held in place by screws. Theseare readily removed, however, in case of
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