Ask PYS: Power

Richard, on Feb 20, 2012 asked:

I know nothing about electricity, other than it hurts when I lick my finger and stick it in a socket. I was down at my marine store this week and noticed that I can purchase a pig-tail for my 30 amp plug so that I could plug in both "sides" of my boat. One side feeds the inverter (and battery charger), and also services the light weight items like the TV, stereo, etc. The other side feeds my stove, hvac, microwave, etc. Now I realize I cannot have all this stuff running at once, but can I buy the pig tail and plug in both sides? How would I know if I have too much stuff running?

Hi Karel,

You’re right you can have a single 30 Amp shorepower feed two sides of your AC circuits. Both of your AC circuits should have AC analog gauges. You need to make sure that both port and starboard AC draw (as seen on the analog gauges) never total more than 30 amps. For instance you could have 15 and 15, but you could also have 5 and 25. As long as the combined total amp draw doesn't exceed 30 amps. If you do exceed 30 amps the shoreside dock breaker (not the ones on your boat) will blow.