Shore Power Idea and Question

[20dauntless]

I ordered my boat without the shore power option but would still like the ability to charge my camera and laptop. I have a 300 watt inverter I can plug into the cigarette lighter when the engine is on to charge stuff but I'd like to be able to do it more easily when shore power is available.

Could I get an adapter so that I could plug a normal household extension cord into a shore power outlet on a dock? I don't need to charge the batteries on the boat or power built in onboard equipment, but would like to charge other devices. Any thoughts?

 

[rogerbum]

Yes you can get an adapter to go from the typical 30A 120V service to 15/20A 120V service. Others have done similar things. Here's a link to one previous discussion on the topic. You will want to make sure that you also install an inline GFI (ground fault interrupter) or buy a GFI cord set as described within the link. With shore power, the circuitry will be protected already with GFI's but a simple extension cord will not be similarly protected. GFI's add a lot of safety factor when you're playing with electricity around water.

 

[Doryman]

Thanks for the link, Roger -- However, this question went unanswered:

Looks like a good idea but I'm wondering if the GFI will protect you if the supply neut is common to other ckts at the dock?

Warren

 

[thataway]

If I understand the question, Warren, the GFI, which your extension cord will plug into, or one on the boat (portable) will protect you. If hot and neutral are miswired, the GFI will trip.

Double check to be sure that your chargers will not be damaged by a modified sine wave inverter. Most are OK, and I have used a small one for many years to charge AA batteries. But I have heard of some chargers being damaged by the MSW inverters.

 

[Sea Wolf]

Thanks for the link, Roger -- However, this question went unanswered:

Looks like a good idea but I'm wondering if the GFI will protect you if the supply neut is common to other ckts at the dock?

Warren

Warren-

The GFI circuit electronically compares the power flowing INTO the appliance down the hot wire to the power RETURNING through the neutral wire. If there is a difference, it interrupts the circuit, turning off the power in microseconds.

So if the power were to return though another neutral wire other than the one served by the GFI, it would be interrupted.

"How does a GFI work?

Inside of a GFI is a sensor that detects changes in current to the appliance by comparing the current flowing to the appliance and the current flowing from the appliance. A drop off in the current equivalent to about 5 milliamperes turns off all power by tripping a relay within the GFI within a few hundredths of a second. You might hardly even feel the shock, it happens so quickly!"

Source: Increase Electrical Safety With Ground Fault Circuit Interrupters

GLAD YOU ASKED; IT'S BETTER TO BE SAFE THAN SORRY!



Joe. :teeth :thup

 

[Doryman]

Double check to be sure that your chargers will not be damaged by a modified sine wave inverter. Most are OK, and I have used a small one for many years to charge AA batteries. But I have heard of some chargers being damaged by the MSW inverters.

Bob, does this comment relate to the GFI or is it about my Xantrex inverter or :?: :?: :?:

Thanks to you and Joe for the GFI explanation!

Warren

 

[20dauntless]

Bob, I have used the inverter for about 6 or 7 years in the car and it has worked fine with all the chargers.

If i buy this: LINK

Is there any adapter that I can plug into a 15 or 30 amp shorepower outlet that I can then attach to a regular houshold extension cord and then plug that extension cord into the above mentioned GFI protected outlets? I want to avoid cutting and splicing wires together.

Thanks for the help, it is much appreciated.

 

[Doryman]

Is there any adapter that I can plug into a 15 or 30 amp shorepower outlet that I can then attach to a regular houshold extension cord and then plug that extension cord into the above mentioned GFI protected outlets? I want to avoid cutting and splicing wires together.

L@@K HERE for an adapter that you can plug your GFI thingie into.

Warren

 

[SeaSpray]

Yes there are adapters that you can buy. Look at WM or Defender and you should be able to find them.

The safety issue is that you do not exceed the 20A rating of the extension cord. I have a similar set up with the exact same GFCI box as in your link. I bought a heavy duty extension cord to run from the dock outlet to the boat.

If you plug in too many things or a heater that draws more than 20A you could melt one of the connectors or the cord and cause a fire. The dock outlet will still provide 30A. Running a laptop and charging cameras should not be a problem.

Steve

 

[20dauntless]

Perfect Warren, thanks so much!

 

[Jazzmanic]

20dauntless,

Until this year, I simply plugged in a 30amp shorepower cord into the box at the dock, attached a 30amp to 15amp adaptor like Warren showed you, and ran the cord thru our window with a power strip attached to run small electrical items, i.e. computer, phone charger etc.

This year, I decided to make it a little nicer and adopted the method that Sneaks came up with for his boat, Jenny B. Here are the pics of the parts that he (and I) used to spruce it up a little.



It was very simple. You don't need to add the battery charger. All I did was cut the cable from the GFCI cord and wire it into the 15amp inlet. I installed the inlet on the starboard side bulkhead which leads into the galley cabinet. That way, you simply plug in the adaptor cord rather than running it through the window. You can then run a power strip from the GFCI box into the cabin for all of your small electrical needs. You can find these pics and explanation in the Jenny B photo album. Thanks Sneaks for the idea.

Peter
C-Dancer

 

[Doryman]

attached a 30amp to 15amp adaptor like Warren showed you

Note that the adapter I found is male, designed to plug directly into the shore power box. If you want to plug your GFI thingie into your shorepower cord you will need a female adapter.

Warren

 

[Capital Sea]

I installed the same system as c dancer along with a charger. The charger takes one of the gfi outlets and when parked at home the dehumidifier takes the other. This inside gfi outlet also is nice when working on the boat.

 

[thataway]

Warren,
The problem with small chargers and inverters does not apply to GFI protection devices. Some small chargers have become hot, and failed due to the modified sine wave configuration (vs a true sine wave power source). The better inverters have multiple stepped square wave, which is close enough to true sine wave, or true sine wave power, and are safe.

I cannot answer specifically about your Xantrex model. Most likely it will be OK--the ones usually at fault are the real cheapies....but some chargers work on them. Thus is depends on the specifics of the small charger. For example most AA battery chargers work fine. I tend to get cameras, radio, VHF hand held, GPS hand held etc which use AA batteries, thus I can recharge them from the inverter.