I was running my A/C at the dock for about 8 hrs on sat and the 30amp 125v plug felt a little warm. I understand the mechnics of amps and supply vs. demand. The A/C unit is a Duotherm I do not know how many BTU's. My question is how many amps would this thing pull running, I was thinking maybe 10amps? I also had my little fridge cycling. I would assume it was 5-6 amps at any given time. kids were watching movies on 1.5amp TV. I would not think I was ove 25 or so amps at any given time. The shorepower cord is a good 50 footer or so from the dock hookup.

Anyone who is an expert on shorepower and what not please gimme some info.. I made the wife turn the A/C off when she popped some popcorn in the microwave just to be safe.

Thanks in advance,

also if anyone knows a good website to look up or knows the amp draws of like coffee pots, hot water tanks and other small appliances please post up.


BurnsOwner38915.4892592593

A little warm is not abnormal. The cord set is rated for 30 amps and if you have a 30 amp breaker at the dock your in spec.

These female ends on the cord set lose their grip over time and need replacement when they don't grab the male plug securely. Be sure to twist it to lock it in and tighten the clamp ring.

If your pulling a lot of amps it's a good idea to shut off the water heater.

The amp draw depends on the size of the units...I have a Coleman and a Duo-Therm and they each draw about 13-15 amps, depending on the outside temperature.

To determine the amp draw on your appliances, look on the manufacturer's tag and find how many watts are listed. Divide the watts by the voltage (measure the AC volts if you can, otherwise use 120) and the answer will be the rated amperage.

Measuring the voltage is important when on shore power, as long power cords and inadequate marina wiring nearly always result in voltage drops; sometimes down to around 100 volts...and as the voltage drops the amp draw goes up... and the power cord connectors get warmer.

Check the plug at the boat and make sure the socket isn't corroded and that the prongs are nice and clean. Also make sure it's not loose when you plug it in. If you have had this cord set for a long time (say 5 years or more) it may be time for a new one.

Sounds like you were ery close to 30 amps. Good idea to turn the AC off when using the microwave.

Within the last 11 years, I have had two power cords that needed to be replaced due to overheating at the male connector end. I use the standard 30-ampere 50-foot cords. I'm sure I have been drawing up to 30 amps load at times. I don't use A/C, but I do use two 1500 watt heaters in the winter. They're only both on for about 15 minutes to warm up the boat when I first get on. I did a voltage check just the other day and get 120 volts on the boat with the heaters off and 110 volts with both heaters on, so I am getting a 10-volt drop from the source on the dock to the electrical outlet on the boat at about 30-ampere load. This is probably to be expected considering it is a 50-foot cable. But that amounts to a 300-watt distributed power loss throughout the distribution system. If that was all at the connector it would surely burn up in no time. About six months ago I replaced the dockside receptical because it looked like it was starting to overheat. qetoo39017.3492592593

If the only AC power that you are using is the 2-1500W heaters at 110 volts, you're drawing 27+ amps. That's pretty close to 30...What about your refrigerator, battery charger, DC converter, etc?

(3000 watts/110 volts=27.27 amps)

Yes, that's true. I also have a full time refrigerator, an 11-gal water
heater and a full-time battery charger. However, these loads do not
normally operate full time. The boat itself has three 15-ampere branch
circuits, one for the port side outlets, one for the starboard side
outlets, and one for the water heater. I have the two 1500-watt heaters
plugged into seperate sides. The refrigerator and battery charger plug
into the starboard side branch circuit. Fortunately I have never
tripped the dockside 30-ampere circuit breaker, but as you say, it
comes pretty close. I think what I have in my favor is that the shore
circuit breaker doesn't trip immediately unless the current exceeds a
lot more than 30 amperes. The standard for circuit breaker trip times
on aircraft is 115% never trip, 138% trip within one-hour, 200% trip
within 60-seconds. Only higher currents would trip trip faster. So you can
see that they will sustain overloads for some period of time. I think
that's what is getting me by. I'm not likely to operate both electric
heaters for more than 15 minutes. After that I usually turn one off and
reduce the power on the remaining one to half. I also Have a microwave
oven installed, but I always turn off the electric heaters when I turn
on the microwave.

But you can see why a bad shore connector will readily overheat at those loads.





qetoo39017.7376273148