Raritan Reverse Polarity Alarm for Shore Power

The Raritan Reverse Polarity Alarm warns of incorrectly wired 120V dockside shore power with an audible signal.

Reverse polarity means the hot and neutral conductors have been swapped somewhere in the dock wiring. The boat's equipment still works, so there is no obvious sign anything is wrong. What has changed is that conductors expected to be at neutral potential are live, and anything touching them completes a circuit.

Many boats already have a reverse-polarity light on the AC panel, and the argument for an audible alarm is simply that it is harder to miss. A warning lamp among a row of other lamps gets overlooked at the end of a long passage, which is exactly when people stop paying attention.

It is most useful for boats moving between marinas, where wiring quality and outlet condition vary from pedestal to pedestal. A home berth gets checked once and stays known. An unfamiliar pedestal does not, and older docks are where the problem turns up. Explore more shore power accessories.

• Warns when hot and neutral have been swapped
• Equipment still works, so nothing looks wrong
• Audible is harder to miss than a panel lamp
• Most useful when moving between marinas