Hi, Gang

I've owned a Triplett 3413-A emission type tube tester
for more than 30 years, and I always made a practice
of pulling just enough a.c. cord from the panel
of the unit to reach the outlet, leaving the remainder
of the a.c. cord hidden away within the cabinet.

I can't believe how lucky I was that nothing shorted out.
I had occasion to open up the unit to correct the a.c. "line"
meter reading, and I noticed that the "stopper"
attached to the cord which keeps the a.c. cord
from being pulled too far out of the cabinet
is actually made of metal. By leaving unneeded a.c. cord
within the tube tester cabinet, the metal "stopper"
could have shorted anything out, damaging either
a tube under test or the tube tester itself.

73,
Ed Knobloch