š Key Concepts
ā¢ Compare the insulation resistance values shown (kĪ© vs MĪ©) and what they mean about a ground fault.
ā¢ Notice how conductors v and w are connected or disconnected between figures 3, 5 and 6.
ā¢ Think about how opening the switch and disconnecting one conductor should isolate which side of the circuit is grounded.
š Think About
ā¢ In figures 3 and 4, when v and w are tied together at the fixture, which test point shows the low resistance to ground, and what does that imply about where the fault might be?
ā¢ After the wire between v and the fixture is disconnected in figure 5, which conductor (v or w) still shows the low resistance reading, and which now shows a high resistance?
ā¢ If a conductor is truly clear of grounds, what insulation resistance range (kĪ© vs MĪ©) would you expect to see on the tester for that path?
ā
Before You Answer
ā¢ Identify which readings are very low (indicating a likely ground fault path) and which are very high (indicating good insulation).
ā¢ Track, stepābyāstep, whether the low-resistance reading stays with v, moves to w, or disappears as connections are changed.
ā¢ Before choosing, be sure you can say clearly: 'Conductor v is ___ of grounds' and 'Conductor w is ___ of grounds,' based only on the final test setup in figures 5 and 6.