A Test Probe is a must have when wiring your doll house.
It is highly recommended that you use the test probe after every
connection you make to be sure it is a good connection rather than
try to turn on the lights after wiring and not know where your
problem is located.
Be sure to turn the power to your wiring off when making connections
and turn on to use the Test Probe. Turn off the power when the
probe lights and continue with your wiring until the next connection
and repeat.