Simple, very basic AC electrical layout

Jackdaw · Feb 16, 2012

I would go from your shore power plug to this breaker panel.

http://bluesea.com/category/106/87/products/8077

And then to gfi outlets.

If you had loads that needed turning off (hot water, refridge), I woud think about a more complex panel but for your listed requirements not needed. You'll be AYBC compliant, and better sorted than most 26 footers with shore power.

Maine Sail · Feb 16, 2012

Squidd said:
OK, I like that.. Just a main 30 (instead of 15-20 which I couldn't find anyway) and then do I wire the outlets as seperate circuts with 3 gfis ? or is one circut in series with one gfi sufficient...?

No, that is a main breaker only and should not be used for branch circuits.. Even for a "simple" AC installation you need an AC main breaker, breaks white & black and then individual branch circuit breakers which break the black only.

You also should have a revers polarity indicator and be sure your AC/DC grounding is intact. Simple AC is not all that simple if you want to do it safely and conform to acceptable safety standards..

I would buy a pre-built Blue Sea panel with the main breaker already installed. You avoid having to tie in your main breaker to a sub panel for branch breakers and this usually saves money.

The smallest AC panel Blue Sea makes is the 8029 but only allows ONE branch circuit.

Image courtesy of Blue Sea Systems

If going to all the trouble I would advise the 8043 as the next step up as it gives you some room for future growth:

There is also the 8049:

The same way you don't wire an outlet in your house directly to the 200A main breaker you don't direct wire branch circuits on a boat to the main breaker.

dparilla · Feb 17, 2012

The only issue with that panel is that it only breaks the hot line coming in. For the best arrangement, you really want a dual pole breaker that can kill the hot and neutral. There are too many ways for stray voltage to occur, and thus being able to isolate both hot and neutral circuits without pulling the shore power cable is essential, trust me it is worth the cost. Lastly, having an exta breaker for future expansion cannot be overstated. You could wire your main outlets to one breaker, your charger to the second and have the third on an outlet dedicated to your heater. That way if you ever bring a blender or high amp device on board, you won't black out just because the heater kicks on at the same time.

Maine Sail · Feb 17, 2012

Squidd said:
OK, we're back to main "and" circut breakers..

Is this brand safe/acceptable..?

I only ask cause they are 1/2 price of what your showing...

Otherwise I think all I need is the single branch circut to power the outlets...

That panel is fine and it DOES break hot/neutral. Paneltronics just uses a single toggle double pole main breaker as opposed to the double toggle double pole main breaker... They do the same thing...

Paneltronics makes decent stuff. I generally prefer Blue Sea quality but the Paneltronics is also very good and if you can find it for that much less it makes it that much better of a deal.......

Bill Roosa · Feb 17, 2012

If all you want is 3 outlets on one circuit all protected by GFI then you can do
AC locking plug - main (hot and neutral) breaker - GFI outlet - outlet 2 - outlet 3.

You only need the secondary breakers to isolate different circuits like if you wanted to have a switch for the battery charger or be able to turn off one of the outlets. Not much call for turning off outlets as it is generally accepted that if it is unplugged it will be turned off and anything you plug in will have its own on-off switch.

SO .....
one circuit, one breaker and put the GFI first in the daisy chain of outlets.

Course if you think you will be upgrading your system later then you are always money ahead to begin with the end in mind. That might lead you to getting a secondary breaker panel with enough breakers to handle all the circuits you think you might need later. Then when you add those you don't need to re-wire the entire boat and can just add that circuit.

Also you mentioned using a heater. These are very high amp/wattage devices and you will want to consider the following:
Will the outlets let you position the heater where it will actually do some good?
Am I overloading the circuit (20 amp 110 is 2200 watts max heater rating) with the heater and other loads?
Running the heater off the last outlet in the daisy chain means the power has to go through the connections at the main and each outlet in between (8 connections total) you might want to consider the order of wiring the outlets so that the one that you will plug the heater into is the first one in the chain.

Maine Sail · Feb 17, 2012

Bill Roosa said:
If all you want is 3 outlets on one circuit all protected by GFI then you can do
AC locking plug - main (hot and neutral) breaker - GFI outlet - outlet 2 - outlet 3.

You only need the secondary breakers to isolate different circuits like if you wanted to have a switch for the battery charger or be able to turn off one of the outlets. Not much call for turning off outlets as it is generally accepted that if it is unplugged it will be turned off and anything you plug in will have its own on-off switch.

SO .....
one circuit, one breaker and put the GFI first in the daisy chain of outlets.

Not a good idea....

A GFCI is NOT a breaker and should not be used as such. They should not be protected by a 30A mains breaker.. This is an immediate flag in a survey.. Also if you burn down the marina and it is discovered that you were protecting 15A outlets and 14GA wire with a 30A breaker.....

If using 14GA triplex AC wire then each branch would get max 15A rated outlet/s and 15A rated single pole branch breaker. The first outlet in the string only need be GFCI.

If using 12GA triplex AC wire then each branch could get max 20A rated outlet/s and a 20A rated single pole branch breaker. The first outlet in the string only need be GFCI.

Bill Roosa · Feb 17, 2012

Hey Main
I'm not trying to size his components for him. Clearly a 30 amp service will support a 15 amp outlet. You would want to protect the circuit properly and I agree putting a 30 amp breaker on a single 15 amp circuit would be a dumb idea. Which is why I made the comment about the heater and his upgrade plans. If Squidd wants to only have one circuit then of course he would be protecting his 30 amp shore power with a 15 amp CB; and he would be money ahead if he want to upgrade later to go ahead and put in a 30 amp main and at least 2 15 amp secondary CBs
I don’t believe I recommended using the GFI as a CB only that it needs to be the first one in the chain of outlets you wish to protect.

Its Friday and we all need to go sailing

Jackdaw · Feb 17, 2012

Maine,

Can you clarify something for me?

I assumed that it was AYBC compliant to go from a AC Breaker panel (like the BSS 8077 I mentioned) directly to GFI outlets ONLY. Is this in fact not the case? I understand it you have hardwired circuits they need to be switched (Refridge, hot water, etc). I've seen this done a lot, and it what Squidd was asking about.

Maine Sail · Feb 17, 2012

To answer a myriad of questions:

From ABYC E-11:

"11.10.2 FOR AC SYSTEMS

11.10.2.1. Circuit breakers shall meet the requirements of UL 489, Molded Case Circuit Protectors For Circuit Breaker Enclosures, or UL 1077, Supplementary Protectors For Use In Electrical Equipment, and

11.10.2.1.1 shall be of the manually reset trip-free type, and

11.10.2.1.2 shall be capable of an interrupting capacity in accordance with table IV-B

11.10.2.2 Rating of Overcurrent Protection Devices - Overcurrent protection devices shall have a temperature rating and demand load characteristics consistent with the protected circuit and their location in the boat, i.e. machinery space or other space. (See E-11.5.1.)
11.10.2.3 The current rating of the overcurrent protection device shall not exceed the maximum current carrying capacity of the conductor being protected.

11.10.2.6 Branch Circuits - Each ungrounded conductor of a branch circuit shall be provided with overcurrent protection at the point of connection to the panelboard bus. Each circuit breaker or fuse used for this purpose shall be rated not to exceed the current rating of the smallest conductor between the fuse or circuit breaker and the load.

11.10.2.6.1 For boats wired with 120 volt, single-phase systems, branch circuit breakers shall simultaneously open both current-carrying conductors. Fuses shall not be used. (See E-11.17.1, DIAGRAM 1 and DIAGRAM 2.)

EXCEPTION: Branch circuit breakers may open only the ungrounded current carrying conductor if the AC system on the boat is equipped with a polarity indicator, or isolation transformer (See DIAGRAM 3 and DIAGRAM 6).

11.10.2.8. Location of Overcurrent Protection – AC Circuits

11.10.2.8.1 Each ungrounded current carrying conductor shall be protected by a circuit breaker or fuse.

11.10.2.8.1.1 A circuit breaker or fuse shall be placed at the source of power for each circuit or conductor except that

11.10.2.8.1.2 if it is physically impractical to place the circuit breaker or fuse at the source of power, it can be placed within seven inches (178 mm) of the source of power for each circuit or conductor, measured along the conductor.

11.10.2.8.2 Simultaneous trip circuit breakers shall be provided in power feeder conductors as follows:

11.10.2.8.2.1 120 volt AC, single phase - ungrounded and grounded conductors (white).

11.10.2.8.3 Additional Overcurrent Protection - If the location of the main shore power disconnectcircuit breaker is in excess of 10 feet (three meters) from the shore power inlet or the electrical attachment point of a permanently installed shore power cord, additional fuses or circuit breakers shall be provided within 10 feet (three meters) of the inlet or attachment point to the electrical system of the boat. Measurement is made along the conductors.

11.17 APPLICATION OF TYPES OF SHORE POWER CIRCUITS

11.17.1 Single Phase 120-Volt Systems with Shore-Grounded (White) Neutral Conductor and Grounding (Green) Conductor. (See DIAGRAM 1, 2DIAGRAM 2 and 2DIAGRAM 3.)

11.17.1.1 The shore grounded (white) and ungrounded shore current carrying conductors are connected from the shore power inlet to the boat's AC electrical system through an overcurrent protection device that simultaneously opens both current-carrying conductors. Fuses shall not be used instead of simultaneous trip devices. (See E-11.10.2.8.2.)

11.17.1.2 Neither the shore grounded (white) neutral conductor nor the ungrounded current carrying conductors shall be grounded on the boat. (See E-11.5.5.2.1.)

11.17.1.4 The shore-grounding (green) conductor is connected, without interposing switches or overcurrent protection devices (See E-11.5.5.5.), from the shore power inlet to

11.17.1.4.1 an optional galvanic isolator, and then to

11.17.1.4.2 all non-current carrying parts of the boat’s AC electrical system, including

11.17.1.4.3 the engine negative terminal or its bus."

The absolute bare bones AC system that meets current safety standards includes a double pole breaker with reverse polarity and individual branch breakers that are single pole. If you do not have a reverse polarity indicator then branch breakers must also be double pole and break both hot and neutral..

An optional galvanic isolator is ALWAYS a good idea..

Bill Roosa · Feb 17, 2012

I believe a bare bones system does not require branch breakers if there is only a single circuit.
My reasoning is from 11.10.2.6 where it indicates that
Each ungrounded conductor of a branch circuit shall be provided with overcurrent protection....
But in a single circuit there are no branches so you do not need to have a main breaker and an additional "branch" breaker.
Of course the same argument MS made in post #10 would still apply and the main CB would be sized to protect the single circuit. In this case a 15 amp CB even though the shore power is a 30 amp service. It is all about protecting the circuit and does not matter if you have a 15 amp or 10000 amp service.
Not that I think that is smart from the financial side of the argument as once you add AC to the boat your demand for AC will grow and you will, no doubt, want to avail yourself of the additional 15 amps (this case) of service. That would require that there indeed be branch circuits and the required CB to support them and an polarity indicator ....... Even if you don't decide to upgrade your AC to the full service level you might want to consider the next owner and resale value of having a system that can be upgraded without rewiring the whole mess.

Jackdaw · Feb 17, 2012

Bill Roosa said:
I believe a bare bones system does not require branch breakers if there is only a single circuit.
My reasoning is from 11.10.2.6 where it indicates that
Each ungrounded conductor of a branch circuit shall be provided with overcurrent protection....
But in a single circuit there are no branches so you do not need to have a main breaker and an additional "branch" breaker.
Of course the same argument MS made in post #10 would still apply and the main CB would be sized to protect the single circuit. In this case a 15 amp CB even though the shore power is a 30 amp service. It is all about protecting the circuit and does not matter if you have a 15 amp or 10000 amp service.
Not that I think that is smart from the financial side of the argument as once you add AC to the boat your demand for AC will grow and you will, no doubt, want to avail yourself of the additional 15 amps (this case) of service. That would require that there indeed be branch circuits and the required CB to support them and an polarity indicator ....... Even if you don't decide to upgrade your AC to the full service level you might want to consider the next owner and resale value of having a system that can be upgraded without rewiring the whole mess.

Bill,
Thanks that was the root of my question, and I don't have the entire E-11 spec. I think its relevant for small (23-26) foot boats that have very limited AC needs. I agree that if you expect your AC demands to grow, plan for it.

Bill Roosa · Feb 17, 2012

Always best to begin with the end in mind.
It also helps the community steer away from the "rats nest" of wires we find on some boats if we all consider how the system might be upgraded by the next guy.
I know on my boat I pulled out 3 different sets of navigation power and signal wires that where just laying there not connected to anything. Trying to make heads or tails of the mess was difficult till I got it down to the single SeaTalk system she has now.
Now if I could just figure out how to get my mast and rigging to resonate as a high frequency antenna from 3 to 20 MHz without having 8 different feed points....

tkanzler · Feb 17, 2012

As far as the NEC goes, a 15A duplex receptacle outlet (NEMA 5-15 type) is considered two receptacles, and can therefore be supplied by a 20A 120V branch circuit. They're rated for 20A supply, and for 20A pass-through.

Is this consistent with the ABYC standard for marine electrical systems, or do receptacles on 20A BC's have to be NEMA 5-20 style?

Bill Roosa · Feb 17, 2012

I'm pretty sure the code allows you to put several (don't know the max) 15 amp outlets on a single 15 amp circuit. I know my boat has 4 on one and 3 on another. The total amp draw IF you plugged in lots of stuff still has to fall below the 15 amp max.
I believe the reasoning is it is not likely for you to plug in enough appliances and run them all at the same time to get a greater than 15 amp draw. In any case if you do you just pop the 15 amp CB and then you realize the heater and coffee pot can't be on at the same time. With that reasoning you could put any number of outlets on a single circuit. I gota believe there is a rule for the max number though and it makes more sense to have the outlets spaced around the boat. There would be no advantage to putting 2 outlets side by side so you could run more stuff if you are limited to 15 amps total. Basically your placement of the outlets precludes putting too many on one branch circuit. So one in the Vee birth, one in the head, two in the cabin (port and starboard) one at the galley and two in the aft birth(s) total 8 outlets but half are on the port and half are on the starboard so break then into two circuits (port and starboard) to save the hassle of trying to daisy chain them all together and to give the full 30 amp service in the biggest rooms.

Maine Sail · Feb 17, 2012

Bill Roosa said:
I believe a bare bones system does not require branch breakers if there is only a single circuit.
My reasoning is from 11.10.2.6 where it indicates that
Each ungrounded conductor of a branch circuit shall be provided with overcurrent protection....
But in a single circuit there are no branches so you do not need to have a main breaker and an additional "branch" breaker.
Of course the same argument MS made in post #10 would still apply and the main CB would be sized to protect the single circuit. In this case a 15 amp CB even though the shore power is a 30 amp service. It is all about protecting the circuit and does not matter if you have a 15 amp or 10000 amp service.
Not that I think that is smart from the financial side of the argument as once you add AC to the boat your demand for AC will grow and you will, no doubt, want to avail yourself of the additional 15 amps (this case) of service. That would require that there indeed be branch circuits and the required CB to support them and an polarity indicator ....... Even if you don't decide to upgrade your AC to the full service level you might want to consider the next owner and resale value of having a system that can be upgraded without rewiring the whole mess.

I actually spoke with John A. today of the ABYC (VP, Technical Director and all round final word on standards interpretation), had to call for another reason, and he confirmed what I wrote above.

The only way to meet the applicable safety standards, if you need "branch circuits", like an outlet, is to use "Drawing #3" which I can't post now because I'd actually need to scan it in, but is as I described a double pole main then off to branch breakers...