Simple AC shorepower system

JonnyBoats · Post by **JonnyBoats** » Sun Jun 03, 2007 5:16 pm

As part of repowering my Northeast 38 I am totally re-doing the electrical wiring. The original electrical panel has AC and DC combined in the same panel, which I understand is no longer considered "best practice".

Since I have a mooring, I have no desire to have many AC appliances like microwaves and A/C aboard. I _think_ I would like to have a simple AC power panel however as I already have the 30 Amp connector mounted as well as a shore power cord.

What i the simpliest sort of setup that would give me a couple of outlets and a connection for a battery charger that would also be consistent with current best practice?

Ceasar Choppy · Post by **Ceasar Choppy** » Sun Jun 03, 2007 10:56 pm

I think you just answered your own question. The complexity comes in when you start adding lots of stuff-- especially an inverter to run that microwave underway or at anchor.

A simple panel to accomodate your needs is all you really need. Make sure the main breaker is double throw (hot and neutral). Wire up what you want to the panel with 10/3 wire (12/3 minimum). Make sure your panel is covered on the back, and use GFIs for outlets. When you connect wire to Home Despot bought outlets, use forked terminals with the bent ends instead of trying to get tighten down the screws on ring terminals.

If you want to get fancy, install a galvanic isolator on your green ground between your inlet and panel... that way you can connect your green from the panel to your boat's main ground strap.

That's about it.

JonnyBoats · Post by **JonnyBoats** » Mon Jun 04, 2007 4:14 pm

A simple panel to accomodate your needs is all you really need.

Any recommendations?

Post by **Tim** » Mon Jun 04, 2007 4:22 pm

This one from Blue Seas is about as simple as they come: 30 amp main, reverse polarity indicator, and a single circuit for your receptacles. Put in wiring, breaker, and receptacles suitable for 20 amp current and you can run most any appliance off the circuit if the spirit--and docking circumstances--should dictate.

Link: Blue Seas 8029 from Jack Rabbit Marine

Hirilondë · Post by **Hirilondë** » Mon Jun 04, 2007 7:29 pm

My shore power system is one breaker more complicated than Tim shows and uses a Blue Seas panel. One circuit is for a GFI outlet for my battery charger and the other is for another GFI outlet for cabin use. Two circuits really aren't necessary unless you expect to charge batteries and power other stuff at the same time or work on the boat using shore power instead of extension chords. I will likely only do that during the winter when working on the boat, and even then I could get around it. My main breaker is 30 amps, and each circuit is 20 amps. I like the convenience of leaving my shore power chord set up all winter and be able to just plug it in to get heat, power for tools and added 120V lighting for working when ever I want. During sailing season I will likely just use it a couple times to charge my batteries.

Ceasar Choppy · Post by **Ceasar Choppy** » Tue Jun 05, 2007 10:13 am

The nice thing about the GFIs is that if you daisy chain more outlets on the same circuit, you only need one GFI at the start of the chain.

The other thing I have considered lately, as Dave suggested above, is that if you wire in "permanent" appliances such as a battery charger or hot water heater etc., it makes sense NOT to hardwire the appliance to the panel, but to wire up a plug or outlet and plug the appliance in. That way, if there is a problem, you have the option of simply unplugging the offending appliance.

s/v Groovy · Post by **s/v Groovy** » Wed Jun 06, 2007 3:21 pm

Here's a couple good articles about AC electric systems on boats.

http://www.practical-sailor.com/newspic ... okedup.pdf

http://www.practical-sailor.com/newspic ... /912ac.pdf

http://www.practical-sailor.com/newspic ... enwire.pdf

Remember the proper sequence for hooking up to shore power, plugging into the dock should be the last thing when hooking up, and the first thing unplugged when unhooking. Walking around the deck with an energized power cord, especially when forestays and shrouds are natural (and grounded) handholds can be deadly.

I frequently see people walking around holding a plugged in cord, or a cord coiled up on the dock but still plugged in to power. Makes me cringe.

I am also installing a new AC system, and will post pics when done.

AC is fairly simple, but deserves respect.

s/v Groovy · Post by **s/v Groovy** » Wed Jun 06, 2007 5:05 pm

Remember the proper sequence.....

Sorry if this came across as 'preachy' I almost lost someone very close to me last year, due to a ground fault from a shore power cord.

JSmith · Post by **JSmith** » Fri Jun 08, 2007 6:23 am

I think the galvanic isolator is important if you leave your boat at a marina or dock with alot of other boats plugged in - From what I understand it prevents your hull from being the sacrificial zinc for all the other boats around you. Not sure how.

Ric in Richmond · Post by **Ric in Richmond** » Fri Jun 08, 2007 7:41 am

Galvanic isolator "disconnects" your boat from the ground system for the purposes of low voltages, but it allows higher voltages to go to ground.

Think of it as a two way "pressure" activated switch. it takes a high enough pressure (voltage) to open the door, but low pressure will not open the switch.

The trick is the high pressure has to be low enough not to kill you and the low pressure block is high enough to keep you disconnected for corrosion purposes.

See Nigel Calder's book for details.

s/v Groovy · Post by **s/v Groovy** » Tue Aug 28, 2007 2:46 pm

I finally got the varnish on, here is my simple AC panel, breaker, GFCI outlet, and Galvanic Isolator remote indicator....

install this weekend...

s/v Groovy · Post by **s/v Groovy** » Fri Aug 31, 2007 11:22 am

the panel is in, filling the odd shaped opening that was left when a PO extended the starboard galley over the original quaterbirth. But I have a question....

My 30A Guest #2430 Galvanic Isolator requires a 12V DC connection, meaning there is a constant draw form the batteries. My two thoughts are to either connect it to the house battery with a switch so the Isolator is not connected to 12V when shore power is off, but this requires remembering to flip the switch, and would draw down the battery (Guest stated the draw is <1amp). My other solution would be to plug in a 12V power supply connected directly to the Isolator, there by powering the isolator anytime shore power is connected, and not putting a draw on the battery. A 1amp 12v power supply is fairly cheap, but is this a bad idea?

I don't like anything connected to my batteries other than the Bilge pump while I'm gone, or am I over thinking this?

potential power supply

pic of panel in place....

Ceasar Choppy · Post by **Ceasar Choppy** » Fri Aug 31, 2007 3:31 pm

I'm guessing that the Guest Galvanic Isolator requires 12v just to power the warning lights. I have a galvanic isolator a friend made for me with no warning lights (of course I have no idea if its really working, but that's another issue.

Inserting a DC switch might be a good idea. You could also wire in the lights for the AC panel on this switch too so that your AC panel won't glow when you are at anchor and aren't connected to AC.