Tuesday, June 30, 2009

Is This Too Hot?

I spent the day obsessing about the temperature of the shore power cables. The shore power cables on our boat have a rather clever configuration. The boat has two 50 amp connectors and our slip has two 30 amp plugs so we have run two cables to the dock with two shore cables that have been configured with 50 amp plugs on the boat end and 30 amp plugs on the dock side so we don't have to have conversion cables and the additional connections. With two shore power cable connected we can select on the service panel to have the Air Conditioners (A/C) to be dedicated to cable #2 so that the A/C and only the A/C runs off of that connection. All other 120 VAC loads are on cable #1. On the dock the 30 amp plugs are in the deck box, one facing out and a second that was added later is inside the box. Both have 30 amp breakers.

We have three Air Systems units on the boat: 1) Model VRP16K (16K btu) in the main salon, 2) Model CMP12K in the Pilothouse, and 3) Model CMP 12K down below with ducts to the Main and Center staterooms. With the two 12K A/C running the #2 cable plug at the dock is at 104° to 107°F. This is with an ambient air temp of 92° F. Cable #1 has a temp of 101° F.

I've switched the function of the cables so the A/C cable is connected outside the box with similar reading so being inside the box does not cause the temperature of the plug to increase. Running all three A/C will raise the temp of the plug to 112° F. My concern is this too hot?

I inspected the plugs and there is no sign of overheating, no discoloration or burn marks. We have not thrown a breaker on the dock in the three weeks we've been here even when we have all three A/C on and running the washing machine, a Splendine 2001.

We'll be watching this closely to make sure that we don't burn the plug or cable during the summer. If we lose a shore power cable we'll be in trouble trying to run the A/C's and during the summer the A/C is not a luxury, it's a necessity.

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