Dedicated shore power for onboard air conditioner ????

[woodster]

ok it's getting hot down here and i have onboard ac .....now it is wired in the the maine panel...via a 30 amp single breaker on the acv panel......i am wondering how to add an extra shore power cord through a new 30 amp deck fixture ...that's the easy part...but when i feed the power to the panel should i treat it like a maine breaker on its own or can i wire the hot leg to the single pole breaker and connect the neutral and ground to the buss bars that are in place now granted i isolate the breaker from the grid in my panel or do i need to have an extra maine breaker in the panel on its own and then a single pole breaker from there to the ac ...its a power hog and makes it hard to run the micro wave and the other things at the same time...i do have an extra dock side outlet available ....i will have to check and see that the two outlets or not on the same hot leg at the dock

 

[Chief RA]

If only one main switch dockside then you are on one 30a or 50a leg regardless of the number of outlets. I'd solve that before I spent any money on anything. Chief

 

[Stu Jackson]

This may go somewhere close to answering your question:

http://www.cruisersforum.com/forums/f14/question-on-twin-30-amp-shore-power-service-166852.html

You have to decide how you want to handle the "incoming" but don't mix the neutrals.

 

[Bill Roosa]

If you plan to use an inverter while under way then you need to consider how to handle the extra AC circuit which should not be energized by the inverter due to the high load. My source selector switch does this automagicaly because I have a separate buss for water heater and AC. It can get really complicated to explain as the WH is also on the main buss but is switched out (it is a single circuit and not on a buss proper) of the main buss when operating on the inverter. You are getting in to fairly deep water here and might want to buy a book or seek professional help.
To answer your question; all incoming circuits should have a main breaker. At the shore power inlet to the boat is best as then the whole system is protected. You can leave this on all the time BTW.

 

[woodster]

You have to decide how you want to handle the "incoming" but don't mix the neutrals.

that is a good read stu thanks

 

[woodster]

If only one main switch dockside then you are on one 30a or 50a leg regardless of the number of outlets. I'd solve that before I spent any money on anything. Chief

i have given that some thought as well thanks chief

 

[rjarrell]

I ran a dedicated 30 amp wire to a separate 5 breaker panel. Two 30 amp power cords to 50 amps on the pedestal through a splutter. Simple installation that has worked flawlessly for many years.

 

[woodster]

You have to decide how you want to handle the "incoming" but don't mix the neutrals.

i think i am going to use a double pole breaker and put the hot leg on one pole and the neutral on the other pole and ground on the buss ...only reservation i have at this time is ....if i do it this way am i going to have trouble with reverse polarity at some time between the house system and the ac aux system incase the power at the dock is not correct on one or the other plugs......the more i think about this if one is reversed and i have the neutrals separated one should not affect the other......

 

[BigEasy]

Woody,
There are different ways to do this. I can only tell you how Beneteau configured their installations.
There are two separate 30amp power cord receptacles on the transom, fed into two separate double pole breakers for each circuit mounted inside a lazarette, approximately 1 to 2 feet from the 30 amp inlets. There are independent triplex 10 or 12 guage wire feeds into two separate AC breaker panels located above the chart table. One panel has breakers for the battery charger, AC receptacles, and water heater. The other panel has breakers for the Air Conditioner. My boat didn't have a factory installed air conditioner. The previous owner had a marine air contractor install the system. The contractor wired the unit into the existing breaker panel for the charger, AC receptacles, and water heater without installing a dedicated power source. Beneteau specifically warns against this practice and specifies that an entirely separate circuit should be installed for the air conditioner. I have purchased an additional "smart plug" power cord receptacle, double pole breaker, and the separate air conditioner breaker panel that Beneteau used on my model boat. This will be the next project on the list. As far as the dock is concerned, you will need two separate 30 amp recepatacles or one 50 amp with a splitter.

 

[Chief RA]

Woody, all AC at your slip outlets are from the same drop, meaning they are in phase with each other at the outlets. Is your slip 30a or 50a as that is the most important point at this stage? Total all of the boat AC current draws you might have and see if it could run on a 30amp ckt. I suggest you contact Maine Sail regarding separation requirements as I suspect a 2nd power cable is not needed as long as your one is rated for the max draw. Splitting power immediately at boat power input should be enough isolation for the Air. Cond.. Good luck, Chief

 

[woodster]

. I suggest you contact Maine Sail

i was hoping that he would shed some light on this

 

[Gunni]

Dedicated breaker and supply leg for your A/C. The amperage needed is too high to chance overloading your existing 120vac supply.

 

[woodster]

there are two 30 amp ac outlets at the power box on the dock ...i have to take a meter and probe the hot legs to see if they are on the some leg ...if i probe the hot legs and they are on different legs then i should read 220 v ac if they are on the same leg i should read nothing .....i need to probe the neutrals and see if they are one and the same or independent....
i am also trying to not have to install a three pole breaker like the main panel has because i have no room for that but i do have room for a two pole that will stand alone from the other power on the same panel face

 

[woodster]

i already have the extra shore power socket on the boat now meaning i have two ss receptacles of 30 amp capacity ...one is not wired in as of yet and that is the one i was going to use a dedicated to air conditioner power with its own dock power cord

 

[kloudie1]

MaineSail will know the ABYC code for that one, Woody. If I recall, a two pole is needed at the inlet if the new main panel breaker is over 10 feet (wire feet and not as the crow flies) from the inlet fitting.
I wired my Air Con into a spare breaker on the existing panel and I have only one inlet fitting. I do not have a double pole breaker at the inlet and the wire is about 10 feet.. I am very careful if I have to run the water heater while air cond is running;I run the water heater for 15 minutes or so, monitoring the temperature of the inlet fitting, then after the water is hot, the heater gets turned off. I don't have a microwave yet since I have not found a suitable place to put one. My 12000 BTU air cond unit draws only 7 amperes when running, water heater 12.5 amperes.. together probably at the limit for a 30 ampere input in kinda continuous service. (dock service cord is 25 feet only)

 

[Stu Jackson]

i am also trying to not have to install a three pole breaker

3 pole? Never want to interrupt the ground. 2 pole. Hot & neutral.

Have you looked into Calder's Boatowners Manual? I'm pretty sure he covers this stuff. If you have two outlets on the dock pedestal and two separate services inside the boat then I'm not sure I understand the issue.

 

[woodster]

3 pole? Never want to interrupt the ground. 2 pole. Hot & neutral.

Have you looked into Calder's Boatowners Manual? I'm pretty sure he covers this stuff. If you have two outlets on the dock pedestal and two separate services inside the boat then I'm not sure I understand the issue.

i didn't word that right ....the main breaker has 3 blocks on it ...2 are for power and neutral...the third one is a latching device to lock out the breaker in case of reverse polarity...if you have rp then it will excite and not let the other 2 stay on till you clear up the rp problem
Shore Main Circuit Breakers with Reverse Polarity Trip Coil

• Shore main AC circuit breaker for Paneltronics electrical distribution panels. 120VAC 60Hz (simultaneously breaks both hot and neutral legs). 220VAC 50Hz (simultaneously breaks both live and neutral legs)
• Reverse Polarity Protector 65VAC trip coil (Surge arrestor P/N 281-001 required) (ABYC E-11.6.3.3.1)
• Smart Breaker: Trips automatically upon sensing reverse polarity.

Please note, all information, specifications and prices are subject to change without notice.

 

[woodster]

3 pole? Never want to interrupt the ground. 2 pole. Hot & neutral.

you correct in what you are saying about the ground

 

[woodster]

MaineSail will know the ABYC code for that one, Woody. If I recall, a two pole is needed at the inlet if the new main panel breaker is over 10 feet (wire feet and not as the crow flies) from the inlet fitting.
I wired my Air Con into a spare breaker on the existing panel and I have only one inlet fitting. I do not have a double pole breaker at the inlet and the wire is about 10 feet.. I am very careful if I have to run the water heater while air cond is running;I run the water heater for 15 minutes or so, monitoring the temperature of the inlet fitting, then after the water is hot, the heater gets turned off. I don't have a microwave yet since I have not found a suitable place to put one. My 12000 BTU air cond unit draws only 7 amperes when running, water heater 12.5 amperes.. together probably at the limit for a 30 ampere input in kinda continuous service. (dock service cord is 25 feet only)

yes that is what i am trying to do and want to make sure i have the safety features in place when all is said and done...so as of now i am thinking i can use a double pole breaker wire to the second power source to run aircon only and put my ground on the existing buss ground and i will keep the neutrals separated this way but i am also worried the the dock power is only one hot leg with 2 outlets on the same run and i don't think that will be a good thing ...it will mix the neutrals in one bundle......

 

[woodster]

after thinking about this some more i am going to wire the power to a two pole breaker 30 amp.....and put the ground on the buss already in place and not worry about the shore power box on the dock...it has 2 .......30 amp outlets with there own breakers .....and plug in to get my power ...even though they may be on the same circuit....if they don't have enough power to run both ....they will just have to fix the problem on there end.......only thing i have reservations about is the neutral being one and the same on those outlets..........