One of the limitations of the tester is that
it will not detect reversal of the neutral and
grounding conductors, which is a possibility if
the receptacle installer was really careless.
However, the grounding terminal on recepta-
cles is always indicated by a green lug, so you
can visually see the error. The grounding ter-
minal is not obvious with the hot and neutral,
and the SureTest will pick it up in a flash as a
reversed polarity condition.“False” Grounds
Since false grounds can create dangerous situ-
ations on a boat and/or in the water around it,
they warrant further discussion. A false ground,
for our purposes, is a ground connection to
neutral at a location other than the source of
power. In other words, it is a point where an
AC neutral conductor is “falsely” connected to
the AC grounding, or earth, conductor.48 electrical systems troubleshooting
Proper neutral-to-ground bonding of an isolation transformer, according to Standard E-11. (Courtesy ABYC).The U.S. National Electric Code (NEC)
only allows a neutral-to-ground link at the
distribution panel for AC systems. The ABYC,
on the other hand, only allows neutral-to-
ground links at sources of AC power on board
the boat—primarily generators, inverters
when they are producing AC, and the second-
ary side of isolation transformer sets, as shown
in the illustrations. If the boat is not equipped
with any of these devices, the neutral and
ground must be separated all the way back to
the shore-power distribution panel. At that
point, the NEC code takes precedence.
Neutral-to-ground bonds are important at
AC power sources because if there is a short
circuit at an AC appliance, it means that the
“hot” has shorted to the equipment case, effec-
tively bypassing the neutral conductor. By
tying the neutral and ground conductor
together at the source of power, the fault cur-
rent is provided with an alternative path back