Wiring up AC power outlets

[crybllrd]

I have an 500w inverter at my nav station which is fine for the bare minimum, but after being in a friend's boat, I saw she had standard home AC outlets in her cabins.

I have a dual USB socket that wires directly to the battery in my cabin, but it would be very nice to have a standard plug socket in the fore and aft cabins.

Is there a special type of central inverter that would allow me to wire up some sockets? If so, what is it called? I liveaboard in Taiwan and we have 110V, 60Hz AC sockets here (same as north america if I remember correctly), so I'd like to have these sockets.

Also, side question: if I can't wire up standard sockets, is there any danger/issues in wiring multiple inverters to a battery bank?

[a64pilot]

First I assume your boat has no AC outlets now? If it does, then I believe the safest and best way to power the AC system is by using an inverter / charger. It is wired into the boat in the shorepower side of things and will power everything shorepower does, but also will prevent the inverter and shore or generator power paralleling.
It also gives you an additional battery charger.

However if all your after is two plugs in separate locations, it may be simplest to just add a second inverter. You can have as many as you like just don’t connect more than one to the same AC circuit. I’m not sure what would happen, but I’d assume the phase may not sync.

Obviously it’s not free power and will use significant battery power.

AC wiring is simple, just do NOT use house wire, use multi strand wiring meant for boats and be sure to use the correct three wire, wire. US wire color is green, white and black.

[DefinitelyMe]

Yes you can do that. Three wires - hot, neutral, ground. Don’t confuse them!

The larger inverters generally are designed to be wired into sockets of the type you describe. The smaller ones tend to have just a couple of sockets on the unit itself. In that case you just need to put a male plug on the end that feeds your socket network and plug that into one of the inverter outlets. Be sure total loads do not exceed the maximum output of a single socket (typically about 15A).

No there’s nothing wrong with wiring multiple inverters to a single battery bank, but be aware that the loads drawn by inverters can be very high, and as such they require large-diameter, short-run cables. Better to have the inverter(s) as close as possible to the battery bank and run the power through the boat at the higher (110-120V) voltage.

[GordMay]

Originally Posted by DefinitelyMe

... Be sure total loads do not exceed the maximum output of a single socket (typically about 15A)...

A 500 Watt 120V inverter will only put out < 4 Amps.

[Kelkara]

Originally Posted by GordMay

A 500 Watt 120V inverter will only put out < 4 Amps.

yes, but 40 amps on the 12V side ... so make sure the 12V wiring is sufficiently large (AWG 6 or 8?) and appropriately fused.

[Ken Pole]

Unforget ground-fault interrupters

[stormalong]

Originally Posted by Ken Pole

Unforget ground-fault interrupters

What does that mean? I have GFCIs in my boat, used with both inverter and shore power and they work fine.

[Ken Pole]

I think they have the same function. That said, GFIs are essentialyy protected electrical outlets while GFCIs seem to serve more as a circuit breaker at source. Redundancy never hurts when dealing with electrical protection in the marine environment. Happy to be corrected. Cheers from Canada.

[CharlzO]

On my 28, there was AC present via shore power, only usable when plugged in. I removed all the shoddy wiring to the shore plug, but left the outlets in place. I then installed a 750/1500 peak watt inverter to my house bank, and then wired in one of the AC outlets to a plug, into the inverter. I only needed one outlet anyway (for my TV and laptop charging) and this allows my inverter to stay in a central location, and I can unplug the ac outlet whenever I need to for anything else. It might be easier to route 110v wiring back from the outlet location to the inverter, rather than running 12v wiring and the inverter up to that spot. Just food for thought, there's a lot of options.

[stormalong]

Originally Posted by Ken Pole

I think they have the same function. That said, GFIs are essentialyy protected electrical outlets while GFCIs seem to serve more as a circuit breaker at source. Redundancy never hurts when dealing with electrical protection in the marine environment. Happy to be corrected. Cheers from Canada.

GFIs and GFCIs are the same thing. What I do not understand is your comment to unforget them. What does unforget them mean?

[Mike Banks]

There is nothing to prevent you using ordinary house wiring for AC. It is DC that causes the corrosion of house wire aboard.

BUT you must run all wiring in ducts. I had both DC and AC outlets on my vessel, and I used tubular glued PVC conduits for all AC outlets. Domestic outlets are fine for marine use with AC from either shore power OR inverters, but I used a switch box containing fuses where the AC comes aboard so that an overloaded circuit did not trip any marina supply overloads.

DC outlets are not interchangeable with AC, one has to use different plugs for each and one will not fit the other. NEVER USE DOMESTIC OUTLETS AND PLUGS FOR DC or vice versa. You can use AC switches for low-amp DC uses, they are designed to carry a low 10 amps--but I do not recommend it.

I use DC switches and 30 amp, 20 amp or 10 amp platinum point relays for DC wiring, but my wiring is done differently to most vessels. Only the light 2mm tinned elay activating wires go to any switchboards, and all items are fused locally on each relay switching power from master bus-bars. DC wiring is HEAVY--I used tinned 6mm wire and I used it in rectangular re-openable conduits. DC wiring HAS to be tinned or one leg will corrode.

I used heavy duty mercury relays for heavy loads such as electric winches, anchor windlass and if I had used one, a bow thruster. Relays solve SO MANY problems and they can be GAS safe--something not many switches are.

[GeneM]

I didn't trust myself to wire my 4KW inverter to the same plugs used by the generator and shore power and didn't want to pay a pro. So, I dedicated a few plugs to always be on the inverter.

The battery charger (Pronautic 50 - love it) keeps the batteries perfectly up and the inverter powers the cabin sockets and frig.

The inverter is close to the house bank, so 12v heavy cables (marine tinned) are short (200 amp fuse on the red). Using many inverters will be very expensive for running long expensive 12v wires.

Ground smartly on the 110v green. I ground to my plate zincs. Don't connect in upstream of your grounding plate.

[landlockedgm]

As A64Pilot stated DO NOT USE regular house wire. Corrosion is not the issue. Solid wire will break from the vibration on a boat.

[joelhemington]

Originally Posted by landlockedgm

As A64Pilot stated DO NOT USE regular house wire. Corrosion is not the issue. Solid wire will break from the vibration on a boat.

Yep, stranded #12 THWN is the way to go preferably in flex conduit.

[a64pilot]

If you desire a large enough inverter to run the whole AC side of the boat, and in my opinion it is the best way.
Use an inverter meant for marine use, for one thing it will have a switch internal to itself that will bind the neutral and ground together, but only when it’s on, because you only want the neutral and ground bonded at the source, and if the inverter is on, then it’s the source.
But if a generator is on, it’s the source, and if your on shore power, it’s the source.
Secondly a large marine inverter should be wired into the shorepower line prior to the circuit panel, it will only allow itself to be connected if there is no shorepower or generator power, you can’t mess it up, it’s automatic.

I can tell you from experience what happens if you connect shorepower when your inverter is connected, it kills the inverter.
Also if you chose to do the double ended male wire so that you backfeed power to the AC system through a wall outlet, be darn sure you always make that connection to the inverter, last. Otherwise you could be holding a hot male plug and give yourself a shock.

For safety and ease of use etc, a good inverter / charger wired in like it’s supposed to is the best way.

I see no reason for conduit myself, and have never seen it on a boat, but there are many boats I’ve not seen