Shore Power Question

[GBNI]

Discovered that aircon system will only work when shore power is connected to one of the two forward power inlets.
Is this normal, will I need two shore power leads to run aircon and the other systems at same time?

 

[rgano]

More than likely you cannot run everything on the boat from one input unless there is internal switching. In order to avoid overloading my single input, I added a second inlet for a second air conditioner. Only that ac ran on that circuit. You should plug in one inlet at a time and see what will operate and then label them.

 

[Hippocampus]

Common to split functions so many boats have two 30a plugs or four (a set of two fore/aft or port/starboard). One is dedicated for AC at each spot. The other for the rest of house draws.
50a boats may not have that set up as well as smaller 30a boats. So yes, if your boat is set up that way you will need two cords. Personally have avoided using a splitter. Be interested in other’s opinions about using splitters.

 

[jgwinks]

My current boat has dual 30 amp inlets but only one 30 amp cord and a splitter. Believe the prior owners had only one 30 amp shore outlet available so no point in having two cords. Mine will run both AC's on this single cord, but unknown what happens if the water heater comes on. Since it decides on it's own when the water is cool enough you never know when it will do that. I rarely use both AC's so I have never really tested it. I do know that if I'm running both AC's on generator and switch to shore power, it will trip the shore pedestal breaker. Can't hard start both AC's at the same time. If I turn them off before switching I can turn them on one at a time and that works.
But yes, if you have dual inputs often the AC's, water heater, and electric stove if present are on one input, everything else on the other.

 

[AlanT]

Personally have avoided using a splitter. Be interested in other’s opinions about using splitters.

I don't blame you! I see their main weakness being the connections which inevitably are exposed to the elements and lying on the dock where they can get kicked, flooded, fall in the water etc.

Learned this to my cost the other day. I have a retracting 50amp cord but have to connect it to a splitter at my marina as my only shore power access is two 30 amp outlets. The boot for the 50 amp cord was never installed correctly and the screw-on sealing ring would not connect to the splitter threaded sealing ring which I noted when purchasing the boat but it slipped progressively to the back of my mind until last week when returning to the boat I found this. Note this occurred on the concrete walkway not where photographed here.

~A

 

[jgwinks]

Since I only have one cord my splitter is up on deck and under my control. Still not ideal as you have up to 60 amp capacity connected to a 30 amp outlet. Your going to trip the breaker eventually.

 

[AlanT]

Since I only have one cord my splitter is up on deck and under my control. Still not ideal as you have up to 60 amp capacity connected to a 30 amp outlet. Your going to trip the breaker eventually.

Mine is the other way around. I have 2X 30 amps feeding my 50 amp boat.
~A

 

[Bacchus]

I also have 2- 30A inlets but do have a transfer Sw on the 120V panel to be able to run anything from inlet #1. I can run both ACs provided a shed all other significant loads. The splitter sort of accomplishes what the transfer Sw does in that you are limited to whatever the one cord can deliver. In your case the 50A cord is the limiting factor and best practice is to limit continuous loads to 80% of that so 40A continuous.
High resistance (bad contacts) cause heat and looks like what occurred in your case.

 

[catalinajack]

I don't blame you! I see their main weakness being the connections which inevitably are exposed to the elements and lying on the dock where they can get kicked, flooded, fall in the water etc.



Learned this to my cost the other day. I have a retracting 50amp cord but have to connect it to a splitter at my marina as my only shore power access is two 30 amp outlets. The boot for the 50 amp cord was never installed correctly and the screw-on sealing ring would not connect to the splitter threaded sealing ring which I noted when purchasing the boat but it slipped progressively to the back of my mind until last week when returning to the boat I found this. Note this occurred on the concrete walkway not where photographed here.

~A

Alan, surmising from the looks of your 50 amp cord, that is, the yellow insulation suggests that the cord is very old. If it was ever dipped in salt water, corrosion inside would have created more and more resistance as the corrosion infiltrated further inside to a critical point. Plus, the connecting lugs would be worn as well creating even more resistance. Exposed to the elements? My goodness, whether connected to a splitter or directly to a pedestal, the connections are always exposed to the elements. Methinks your meltdown was caused by your old, worn 50-amp cordset.

 

[AlanT]

Alan, surmising from the looks of your 50 amp cord, that is, the yellow insulation suggests that the cord is very old. If it was ever dipped in salt water, corrosion inside would have created more and more resistance as the corrosion infiltrated further inside to a critical point. Plus, the connecting lugs would be worn as well creating even more resistance. Exposed to the elements? My goodness, whether connected to a splitter or directly to a pedestal, the connections are always exposed to the elements. Methinks your meltdown was caused by your old, worn 50-amp cordset.

Thanks for your feedback. I do not disagree. It's an old cord. The boat end is totally protected from weather, and when the shore end is attached to a shore power stand it also is protected from weather (by virtue of the shore power stand designs in this area). It is only when using the splitter that any of the connections are directly exposed to weather. I suspect it is a combination of wear on the shore end plug as you indicate and exposure to the flooding rain we experienced the day prior to my discovery.

When I cut off the remains of the burned connections the wires proved to be in excellent shape with no sign of corrosion/water intrusion into the cable itself. This old cable has a kind of clothlike material wrapped around the wires which was totally dry, and the cables registered zero resistance on all scales of my ohmmeter. With new plugs and boots and sealing rings I feel I am in good shape now. I just wish I had followed my initial instinct and replaced the old misfitting 50amp plug when I first noticed its state.
~A