Wiring question on A/C installation

[belleview3]

I?m installing a stand-alone 120v. HVAC into my ?99 Wellcraft Martinique 2600. It?s a 16k btu unit that?s going to turn my boat into a deep freeze (yep, it?s way oversized, but the price was right). Piping it in and installing the unit behind the aft berth bulkhead should be no problem. My boat has a single 30amp shore power connection that I?d like to use for the source to the unit. The existing load is the baby fridge (5amp), microwave (5amp), battery charger (5amp) and an outlet. The existing source should handle the load, especially if I monitor what is being used. The existing distribution panel on the port side of the boat doesn?t have any additional space for another breaker. Getting the wiring from the starboard side to the port side is going to be a b!@ch. Can?t find any info on how it should be routed (it was an option that wasn?t documented well). May have to get creative.
My question: Should I intercept the line wires above the breaker panel and add a terminal block to add another circuit and breaker or just piggy back another set of lugs on the load side of the main breaker to add the circuit? All of the breakers have screw terminals with crimped ring connectors. I prefer adding the circuit to the load side of the main to keep it as the full-load breaker and switch.

 

[kmarine]

Re: Wiring question on A/C installation

You could add a breaker or piggyback like you said or add a seprare 30Amp coard,outlet, and breaker for the ac unit and run new cables there you need them.

 

[Lyle29464]

Re: Wiring question on A/C installation

Sounds like you have a handle on it. ( you really need to have one master shut down breaker)

 

[Fireman431]

Re: Wiring question on A/C installation

If you piggy back onto the existing wires, you should install some type of disconnect to the AC unit (not 2 breakers on the same line). The only spike you'll have is on initial start up. once the unit os running, it should only pull around 7 amps. For a 16k BTU unit, initial spike will be around 22 amps.

 

[belleview3]

Re: Wiring question on A/C installation

Thanks guys, I initially liked adding another 30 amp connection. The problem is the amount of tearout to get to the location to place another connection through the hull and run the wire (ripping out carpet, trim and cabinetry). Normally, we don't use the microwave, but the charger and fridge would probably be running. Because the unit is soooo big for the area, I doubt the fan will ever get off low. I know a 6-9k btu unit would be a proper size for my boat, but I stumbled on this unit for $80. The previous owner thought it was gong bad because it wouldn't reverse to heat. Turns out the reverse switch was simply hung up because of lack of use. A few taps on the switch while flipping from cool/heat and it started operating normally. This guy spent 2 grand for a new unit because of a sticky switch. I didn't have the guts to let him know.

 

[Fireman431]

Re: Wiring question on A/C installation

I replaced my 16K unit last year. That was a quick $1400 and I though I scored a deal on it. Kudos to you!

 

[CaptainKickback]

Re: Wiring question on A/C installation

I had a 1998 Cruisers 2870 with 2 30 amp shore power connectors. Since most docks don't makes 2 connections easily available, I made a Y cable and ran the boat off one 30 amp source. Never tripped a breaker in 9 years. I had the same equipment as you (fridge, etc).

Good luck...

 

[Fireman431]

Re: Wiring question on A/C installation

Since most docks don't makes 2 connections easily available...

Must be a South Florida thing. Every dock I've ever been at has either (2) 30A circuits, (1) 50A circuit, or both!

 

[belleview3]

Re: Wiring question on A/C installation

The dock I hook up to only has 20amp circuits readily available. I plan to tie into one circuit (10 awg wire) that has the capability of a 30 amp breaker. To add another 30amp circuit will require another 80' conduit run or upgrading / adding a subpanel. Probably more work than the dock owner is ready to donate. We primarily have day slips for weekenders. I've been at this resort / park fo 40 years, therefore I have a little leeway to modify one isolated run, but don't want to push it. I've been using the existing 20amp circuit but the new A/C will definately push the circuit.

 

[CaptainKickback]

Re: Wiring question on A/C installation

Must be a South Florida thing. Every dock I've ever been at has either (2) 30A circuits, (1) 50A circuit, or both!

Many of the distribution pedestals I've seen at docks do have 2 30 amp connectors. However, one of them is for your neighboring boat.

 

[Fireman431]

Re: Wiring question on A/C installation

Many of the distribution pedestals I've seen at docks do have 2 30 amp connectors. However, one of them is for your neighboring boat.

The docks that I'm speaking of have (2) 30A connectors on each side (2 for each boat) or (2) 50A connectors, one for each boat. But then again, I'm speaking of commercial marinas. not rented residential docks.

 

[belleview3]

Re: Wiring question on A/C installation

Ok, hang on just a second. If your dock has only 20 Amp service it's not legal or up to code (NEC 555.19 E). "Recepticals providing shore power for boats SHALL be rated at least 30 amperes and shall be single type". . . . I believe I would have a talk with the owner BEFORE spending time and money trying to make your boat fit an unsafe power supply.

First of all this is a private dock. Secondly, the majority of the circuits are 20amp with standard recepts. Thirdly, there is one 30amp circuit that I can intercept to reroute to the slip I traditionally use that has a standard recept. The subpanel that feeds it doesn't have any spare breaker slots. Therefore if I want to have 2 - 30 amp circuits, I would need to run another circuit to a 2nd subpanel some 80' away.
I have made my own shore power cord with an adapter to fit the standard receptacle so I can use my battery charger. I haven't used the microwave nor fridge while on 120v power. I'll use my regular 30 amp shore power cable when the new 30amp recept is installed. This whole thread has taken a wrong turn. Time to walk away.

 

[Tim Frank]

Re: Wiring question on A/C installation

First of all this is a private dock. Secondly, the majority of the circuits are 20amp with standard recepts. Thirdly, there is one 30amp circuit that I can intercept to reroute to the slip I traditionally use that has a standard recept. The subpanel that feeds it doesn't have any spare breaker slots. Therefore if I want to have 2 - 30 amp circuits, I would need to run another circuit to a 2nd subpanel some 80' away.
I have made my own shore power cord with an adapter to fit the standard receptacle so I can use my battery charger. I haven't used the microwave nor fridge while on 120v power. I'll use my regular 30 amp shore power cable when the new 30amp recept is installed. This whole thread has taken a wrong turn. Time to walk away.

Don't let that get to you.
Sometimes a little bit of knowledge is a dangerous thing....and I am forced to admit, that poster does have that. :facepalm:

He made three points, and got all 3 wrong.
Posting something in quotes that is supposedly an NEC code that refers to "recepticals" (sic) is laughable and ascribes a level of illiteracy to the NEC that is unwarranted. He needs better sources from which to cut and paste.

There are any number of 20 A, receptacles available, from a number of manufacturers. He just needs to get out more.

Until 2008, GFCI were not req'd for shore power supplies. And if he had read your OP, he'd have seen that the installation has been there for 40 years.
I'd spell that "GRANDFATHER", codes notwithstanding.

Nothing wrong with your "recepticals'

 

[seabob4]

Re: Wiring question on A/C installation

Must be spring. Lots of uneasy sorts these days...

 

[belleview3]

Re: Wiring question on A/C installation

Maybe I didn't post my question properly. I was looking for input on adding the A/C circuit ON MY BOAT, not the friggin dock. Fortunately, one of our members has an identical model to mine. He said he will send pictures of how his is wired. Hopefully, that will help. Thanks for the help guys. . . I really do appreciate the feedback.

 

[Fireman431]

Re: Wiring question on A/C installation

Are you wiring this to a genset also or simply wanting the AC while moored at the dock?

 

[belleview3]

Re: Wiring question on A/C installation

Are you wiring this to a genset also or simply wanting the AC while moored at the dock?

Adding a ginny would be difficult. Just about every square inch is taken below decks and I don't want to haul around a portable.