P42 Electrical Question(s)

[Terry Cox]

Some questions about the P42 that I need help with some information.

1. Shore power connection: The boat came equipped with 60 amp service through two 30 amp shore power connections, buss A and buss B. Next to the shore power plugs are two circuit breakers; line 1 and line 2.

A. What exactly do these two circuit breakers do? On our boat whether the breakers are pushed in or popped out, it makes no difference in the power supply to the boat.

B. Connecting a shore power cord to just the inboard plug, power shows at the panel on buss B side, but no power distributes inside the boat including the charger. Why is that? Do I need a shore power cord on the outside plug (buss A) before buss B plug works?

2. Has anyone changed the original 30 amp plugs to smart plugs? Big deal or plug and play? Have you noticed any difference?

Our slip neighbor who has a similar sized boat was experiencing burned plugs on his boat and so he changed over. He uses a standard Marinco 30 amp shore power cord that connects to a splitter. Each of the two splitter female ends are Smart plugs with the single male feed end is a standard 30 amp socket.

I thought I would check here first before contacting Marlow Hunter. Thanks in advance for your help.

 

[rtmccue]

They should shut off the power to buss 1 and 2 or A B . I hope someone did not bypass them

 

[quadrille38]

It is likely that line 1 provides power to the AC services in the boat and Line 2 powers the air conditioning units.

You will either need to run two 30 amp chords from the dock pole to the input outlets on the boat. Some docks have 50 amp service available and people will use a splitter to take one 50 amp and split it to two cords for feeding the boat. Some people will run from the dock 30 amp to the boat and then use a splitter at the boat but then you have to be very careful because you are using one 30 amp service to feed two 30 amp circuits and it is easy to overload them.


Somewhere close to where the power cords enter the boat there will be two breakers - one for each line. They may be located in an aft cabin or in a locker but they are designed to provide a shut off at the point the power enters the boat.


Typically they will then go through isolation transformers before traveling to the main switch panel.

 

[woodster]

as far as the 30 amp power cord feeding two 30 amp plugs that seems to me very inadequate...if you are pulling 60 amps through a 30 amp cord i am surprised that breakers aren't tripping all the time or burning up the cord if you are feeding 60 amps through it way to much power draw for that cord

 

[quadrille38]

as far as the 30 amp power cord feeding two 30 amp plugs that seems to me very inadequate...if you are pulling 60 amps through a 30 amp cord i am surprised that breakers aren't tripping all the time or burning up the cord if you are feeding 60 amps through it way to much power draw for that cord

Exactly especially if you are running the air conditioner hard. Although I will say that on the main cabin circuit the load is actually quite small unless you try to run the microwave, coffee pot or toaster. Those loads added to the air conditioner on line two going through a single 30 amp chord would be a concern just as you've said.


The best solution is really two separate chords but then not all dock power poles have 2 30 amp outlets and you need dual cores

 

[woodster]

Exactly especially if you are running the air conditioner hard. Although I will say that on the main cabin circuit the load is actually quite small unless you try to run the microwave, coffee pot or toaster. Those loads added to the air conditioner on line two going through a single 30 amp chord would be a concern just as you've said.


The best solution is really two separate chords but then not all dock power poles have 2 30 amp outlets and you need dual chords.

i have seen a splitter for the dock end where it hooked in to a 50 amp outlet and split into 2 30 amp females ...just the reverse of the boat end

ps....... with all this splitters and dual cords this is getting very expensive

 

[eianm]

Terry- on mine- the circuit breakers act like switches- "on" I have power- "off"-I have no power to distribution board- looks like yours might have been tampered with?

 

[Terry Cox]

Just To Be Clear

I manage boat power consumption carefully at 30 amps or less. Easy to do with the assortment of gauges. I never try to consume more than 30 amps through one cord. The boat or the 30 amp dock pedestal will not let me do it. My questions pertain more to the information that I provided.

I'm wondering whether the two circuit breakers next to the shore power boat plugs are more for ground fault protection. Each breaker has two black leads connected to one of the two circuit breaker posts. Just do not know the purpose yet.

Normally, AC is black hot and white neutral, with DC red hot and black neutral. If the color code is correctly used the four black wires (two to each breaker) would be hot. I have not tested the wires with a volt meter, yet.

 

[Terry Cox]

Maybe.

Hi Eian, when we took possession of Belle-Vie in 2002 this site referenced me to a Hunter P42 electrical recall notice. Our boat HIN qualified. It basically involved a larger gauge wire between the shore power boat plugs and the main power panel. Hunter paid all labor and materials for the upgrade. I'm wondering, as you say, whether something was tampered with. You would think those circuit breakers would shut off the power, but they do not.

The recall had something to do with a P42 fire that the investigation determined the cause to be inconclusive. Bu† as is with Hunter, they took the high road to do the right thing.

 

[uncledom]

Here is how my 2006 41 is wired. Two separate 30 amp shore plugs that go directly to two isolation transformers, one one each line. The circuits then proceed to a 30 amp circuit breaker on each line, located in the aft cabin up high on the back bulkhead. They are single pole breakers and seem to be there just to protect the wire as it runs more than ten feet before it hits the AC panel. The AC panel is set up as two individual panels each with their own loads. Each panel has a main 30 amp two pole breaker which isolates or connects both the Hot and Neutral wires from the panel. This ensures Neutral isolation of the incoming shore power when using a generator which should be bonding the Neutral to ground. Unfortunately I know from experience that you can, over time, smoke your Neutral wire. Breakers don't trip instantly when you pull more than their rating, it's actually a matter of heat over time. The higher the draw, the higher the heat, the faster the trip. The breaker can be reset after the heat/trip but the heat damage to the wire is aggregated until there is a wire or connector failure. The possibility of this is exacerbated by the fact that the generator can put out more than 30 amps and the panels can be bridged by yet another breaker.
This spring I have an AC rewire project to ensure there is no place on my boat where the available power can exceed the rating of the attached busses or wires. I will try my best to document it thoroughly but I doubt it will be a Maine Sail quality production. I know this next statement will not be met with friendly replies but ALL AC circuits are rated to be in continuous use at only 80% of their rated capacity. This means that you should only be pulling 24 amperes continuously on a 30 amp circuit/plug/ wire.

Hope this helps
Dom

 

[KD3PC]

ON my 1991 P42, the breakers next to the shore power inlets controlled the power heading to the nav station breaker panel. There was either a galvanic isolator or isolation transformer just inside the area behind the shore power outlets.

My breakers did turn off the power to the panel, as I tested that early on. There is a little bit of room behind the outlets and I had a small amount of slack cable to mate to the shore power outlets so that replacing the old style with smart plugs should be fairly easy.

 

[uncledom]

i have seen a splitter for the dock end where it hooked in to a 50 amp outlet and split into 2 30 amp females ...just the reverse of the boat end ps....... with all this splitters and dual cords this is getting very expensive

These are against NEC rules and I have seen local inspectors have the marina staff unplug them for safety. The problem is that you could pull 50 amps on a 30 amp cord and connectors. I applaud them for the effort.

 

[ice breaker]

Some questions about the P42 that I need help with some information.

1. Shore power connection: The boat came equipped with 60 amp service through two 30 amp shore power connections, buss A and buss B. Next to the shore power plugs are two circuit breakers; line 1 and line 2.



Very near where the show power enters the boat will be 2 breakers, one for each shore power connection. Boating code requires that theses be very close to where the power first enters the boat. Like 3-5 feet.

LINE 1 IS HOUSE POWER 30AMP. LINE 2 IS FOR AC. When you only have 30 amp at the the dock, the lines can be combined at the panel with the parallel switch. As it sound like you know, 30 amps ends up being an Apollo 13 effort to manage the amp usage.

I attached two hunter diagrams, that should be similar to what to have.




A. What exactly do these two circuit breakers do? On our boat whether the breakers are pushed in or popped out, it makes no difference in the power supply to the boat.

See above. If the truly do nothing, as others have said, things may have been modified, and that could be a very big safety deal.



B. Connecting a shore power cord to just the inboard plug, power shows at the panel on buss B side, but no power distributes inside the boat including the charger. Why is that? Do I need a shore power cord on the outside plug (buss A) before buss B plug works?

SEE ABOVE, you need to have parallel in the ON position.

 

[Paul Cossman]

P42 AC power

Hi Terry,

Like Eian, my P42 circuit breakers--the ones located under the entry step by the plugs--do function, and they will interrupt the flow of electricity from the shore power plugs. One controls buss A and one controls buss B.

On my P42 I can use either plug receptacle and transfer the AC input via my electrical panel. I can't remember the exact name on the switch, but one of the switches permits me to select which plug I wish to use: buss A or B. I have used either interchangeably, and it transfers AC to the entire boat.

It sounds like your system is operating differently than both Eian's and mine. I'm guessing that whoever did your upgrade may have reconnected things improperly. Can't think of any other reason for the odd responses from the circuit breakers.

Good luck,

 

[woodster]

These are against NEC rules and I have seen local inspectors have the marina staff unplug them for safety. The problem is that you could pull 50 amps on a 30 amp cord and connectors. I applaud them for the effort.

you may be correct but it makes me wonder why marinco makes so many of that type...i always thought a manufacturer would not make something that did not muster up to code ...it does sort of look like putting 2 or 3 appliances on an extension cord

 

[Terry Cox]

Thanks all for your input.

I really appreciate your comments and they have been very helpful. It must have been the electrician who did the upgrade that changed things around. Some easy fixes, it seems. I'll keep you posted as to what I find.

 

[uncledom]

you may be correct but it makes me wonder why marinco makes so many of that type...i always thought a manufacturer would not make something that did not muster up to code ...it does sort of look like putting 2 or 3 appliances on an extension cord

There are many things that can be purchased that are illegal in a particular country or state. The manufacturer does not ask those questions, they just make supplies by demand.

 

[Terry Cox]

P42 Questions

Hi all, I've posted some questions to Marlow-Hunter in hopes they will clarify our boat situation. Shortly after we took possession in 2002 I activated the recall notice with Hunter Marine that applied to our boat. In turn they contracted an electrician to take care of all labor and materials that dealt with the electrical recall.

Since then I have been enjoying the boat, that is until a recent electrical issue cropped up and upon checking found some interesting things. What I hope Marlow-Hunter will clear up is the following:

1. Why did the electrician bypass the line 1 and line 2 circuit breakers at the shore power outlet? Whoever did the work merely connected the in-feed and out-feed wires to the same post on both breakers.

2. Why did the electrician disconnect buss B shore power circuit? I intend to check this weekend to see what is going on in the back of the main power panel. Power appears at the AC volt meter, but does not go beyond to the charger or any other circuit.

Another questions for you, since there is only one main 30 amp circuit breaker on the main panel, how does that work with two 30 amp shore power cords connected? Just sayin.

 

[Terry Cox]

Plan In The Making

Here is what I plan on doing. In all these years I have always used buss A (outboard) shore power plug and managed power consumption accordingly. I figure that that original 1991 plug is wearing out and intend to replace it with a new Marinco brand plug. The inboard plug buss B appears to have no or minimal use and will leave it as is, except to figure out how to activate it.

Secondly, I intend to reconnect the two circuit breakers as they were originally. I'm assuming that Hunter Marine placed them there for a reason, to help protect the boat.

Perhaps the new Smartplugs would be a better way to go, but I figure that the Marinco brand has a stellar reputation in the industry and rather than spend $500 for new plugs, splitter and cords, a new $25 Marinco plug should work just fine.

Would you please let me know if you see any flaws in my dissertation?

 

[Terry Cox]

Shore Power Incident Repair

Went to the boat to install LED bulbs only to find that the shore power Buss A breaker on the main panel was off and had been so for several days. Wondered why. After checking the connections I turned the power back on only to have it shut off again and this time the reverse polarity light came on; very unusual.

There was much resistance when I attempted to remove the shore power cord from the boat receptacle. After much effort it came out and noticed that my almost new cord was burned on the neutral pin and socket; bad enough to melt the cord material. Something had hit the power source, either a power spike or bad cord.

After cleaning the neutral pin, the spare cord worked fine for this past week. My plan was to replace the Buss A boat plug with new as it has been on the boat since built in 1991. In the process I found out why the two Line circuit breakers were bypassed. For some reason the PO had sheared off the head of machine screw that secured one of the wires to the breaker (it looked as though they had tried to force a different machine screw thread onto the terminal). Rather than repair it he/she terminated both wires on the same post on both breakers thus bypassing the breaker safety function.

After fours hours of work both Line 1 and Line 2 breakers work as originally designed, Buss A shore power cord has a new receptacle plug and I learned some new things about the boat's electrical system.

Buss A feeds 30 amps of power to the entire boat including the battery charger. Buss B feeds 30 amps of power only to the two reverse cycle air conditioning systems. The two running along with the sea water pump requires about 25 amps of power. With Buss B feeding power to the heat pumps that leaves Buss A with plenty of power to operate the rest of the boat systems. Now it all makes sense.

Normally, with just Shore Power A cord I select parallel Parallel Buss A/B on the far right side of the panel. That way I can operate at least one heat pump and any other appliance up to 30 amps. At some point if I ever want to connect Buss B cord to run the heat pumps in addition to Buss A cord to run everything else, the panel lets you select Air Cond/Power B, which supplies 60 amps by running both Busses as the same time. See link below.

http://1.bp.blogspot.com/-VsEt0qLk2A0/TfTMIbqElzI/AAAAAAAAAB4/8yP_ibCTj_c/s1600/Parker+Dee+049.JPG