ClipArt ETC
"Illustrating fuse protection for voltmeter and ground detector and ground detector on a direct-current switchboard." —Croft 1920

Fuse Protection on Direct Current Swtichboard

"Illustrating fuse protection for voltmeter and ground detector and ground detector on a direct-current…

"Cut-out ground detector using lamps for a three wire circuit." —Croft 1920

Cutout Ground Detector for Three Wire Circuit

"Cut-out ground detector using lamps for a three wire circuit." —Croft 1920

"Lamp ground detector for a three-wire circuit." —Croft 1920

Ground Detector for Three-Wire Circuit

"Lamp ground detector for a three-wire circuit." —Croft 1920

"Lamp ground detector for a two-wire circuit." —Croft 1920

Ground Detector for Two-Wire Circuit

"Lamp ground detector for a two-wire circuit." —Croft 1920

"Illustration shows a voltmeter ground detector." —Croft 1920

Voltmeter Ground Detector

"Illustration shows a voltmeter ground detector." —Croft 1920