A JOLT OF REALITY

Proper AC safety grounds are necessary to prevent electric shocks-or worse.

- STEVE D'ANTONIO

MONTHLY MAINTENANCE

In our June/July issue, we looked at optional bonding systems, which are typically associated with corrosion prevention (cruisingworld.com/the-valueof-bonding). Closely related to bonding systems are mandatory alternating current safety grounds. If your vessel has an AC power system-supplied by shore power, a genset or inverter-then the safety ground is critically important.

The terms "ground," "bond" and, to some extent, "DC negative" are often used interchangeably. While they are related, they each have a different mission.

In marine electrical systems, a grounded conductor is always common with ground. This would apply to the neutral or white wire in a 120-volt, alternating current (VAC) system. The conductor must always be common with the ground at its source, which includes a dockside utility transformer, onboard generator or inverter, or onboard transformer. The conductor can also include objects that are permanently connected to the grounding system, thereby making them grounded at all times.