Reply To: JCCC3 – Questions for the Site Inspection Cruise?
There is a phenomenon called “ground lift,” in which the ground wires in the electrical system are carrying so much current that they are at a potential that’s significantly above ground. While it’s a sign of a dangerous problem with the electrical system, it won’t blow out a power strip. There’s also a chance that the neutral wire will be above ground potential due to high current in the circuit. But again, this isn’t going to toast your power strip.
What’s more likely is that the output of the ship’s generators is running high for an extended period of time — say, 140 volts or more instead of 120. This is most likely to happen when the ship is running against the wind and the engines are revving high — as they did on the rough, rainy day we had on JCCC2. Most devices — especially computers — won’t care about the difference, because they have electronic (“switching”) power supplies that just adapt to the higher voltage. But the MOVs used in power strips are designed to turn on at at that voltage, and they will blow out if the overvoltage is sustained. You can buy voltage regulators that actually compensate for the overvoltage — I have some for my music gear to handle the power surges that occur in theaters — but they tend to be bulky and heavy. You wouldn’t want to take them on the cruise.
My call would be to take a non-surge-protected power strip on the ship and make sure that all of your devices are either insensitive to higher voltages (a non-electronic device like a hair dryer, for example, will not care if the ship’s voltage is a little high) or powered by switching power supplies. If an electronic device’s power supply says it will handle a wide range of input voltages — say, 90-240V — it’s a switching power supply. It will adapt to extra voltage (and, in most cases, to brownouts) without blowing out. If an electronic device’s power supply says it’s 120V or 240V only, or has a switch that you have to move manually for different line voltages, it’s probably a linear power supply that will be affected by overvoltage. Leave it home.