Q. Can you check Earth fault with Double Test Lamp?
Ans: Double test lamp having three leads. Centre lead could be connected to earth, left side lead should be connected on positive side (+ve), right side to be connected on negative side If both bulbs glow dimly it shows no earth in the coach. If left side bulb glows more brightly it shows negative earth in the coach. If right side bulb glows more brightly it shows positive earth (+ve) in the coach.