Cruisers Forum

Join CruisersForum Today

Thread Tools Rate Thread Display Modes
Old 12-09-2008, 06:35   #1
Registered User

Join Date: Sep 2008
Posts: 5
Electrical help needed please

I am new into sailing/boating in general and have a question about a distribution panel - or switch panel (whichever you want to call it.) I just picked up a 5amp switch panel that I am going to hook my battery up to it. I know it is on the small end of the spectrum in terms of amperage, but can I still use this switch board to run my running lights, cd radio, stereo, cabin lights, etc?

navillusdm is offline   Reply With Quote
Old 12-09-2008, 07:05   #2
Registered User
SelkirkWind's Avatar

Join Date: Jan 2008
Location: Sandpoint, ID, USA
Boat: Leopard 46, The Selkirk Grace
Posts: 73
5 amp switch panel

Here is what you must know, and there is no magic here:

P=VI or in words power = voltage X current
Power(P) in Watts, Voltage (V) in Volts, Current (I) in Amps

You have not said so, but assuming you are speaking of boat power then:
Nominal 12V battery case:
P=12V X 5A= 60Watts Maximum
Add up your loads. If they exceed 60W you will blow the breaker. You could just run one thing at a time (if under 60W) and then the breaker will only blow if you switch anything else on.

In the shore power case with V =120V,
Nominal 120V shore power case:
P=120V X 5A= 600 Watts Maximum
Add up your loads. If they exceed 600W you will blow the breaker. You could just run a few things at a time (if under 600W) and then the breaker will only blow if you switch anything else on.

So what you have learned here is that 5 Amps is a small load. It may have a use, but if you need to drive more electrical and electronic appliances (and what boat ( Bring On All Technology) doesn't), you will need additional breakers or a breaker of increased amperage.

The next issue is wire sizing. All conductors are sized to handle a specific amount of current. I am sure that someone will explain this, if this has not already answered your question.

SelkirkWind is offline   Reply With Quote
Old 13-09-2008, 09:23   #3
Moderator Emeritus
Ex-Calif's Avatar

Cruisers Forum Supporter

Join Date: May 2007
Location: Singapore
Boat: Maxi 77 - Relax Lah!
Posts: 11,514
Images: 4
By panel - I assume you have multiple switches with 5amp breakers. They are breakers not fuses, right?

Because it's not clear by your post but you want to run these things on separate circuits.

IIRC correctly - here's how our panel is split up

10 amp - running & Steaming lights
5 amp - anchor light
10 amp - vhf
10 amp - autopilot
10 amp - cabin lights & outlets (fans)
5 amp - instruments - depth & compass light.
Relax Lah! is For Sale <--- Click
Click--> Custom CF Google Search or CF Rules
You're gonna need a bigger boat... - Martin Brody
Ex-Calif is offline   Reply With Quote
Old 13-09-2008, 09:47   #4
Marine Service Provider
AnchorageGuy's Avatar

Join Date: Mar 2003
Location: Wherever the boat is!
Boat: Marine Trader 34DC
Posts: 4,617
I STRONGLY suggest you not do any electrical wiring to your boat at this time. A mis-step can cause a fire at worst or serious damage to other electrical circuits on your boat at best and if you are in a marina the results could be devastating. You really either need to acquire a great deal more knowledge or get the help of a knowledgeable individual before you start and as you progress. Get a copy of the 12 Volt Bible and study it thoroughly. Obviously from your question this is not something you should tackle at this point by yourself.
Chesapeake Bay, ICW Hampton Roads To Key West, The Gulf Coast, The Bahamas

The Trawler Beach House
Voyages Of Sea Trek
AnchorageGuy is offline   Reply With Quote
Old 06-11-2008, 23:21   #5
Registered User

Join Date: Nov 2007
Location: South East Asia
Boat: 122 year old Historical Sailing vessel
Posts: 121
I have to agree with Chuck mate. If you want get a good book like Marine Electronics Bible or any other that looks like starting out wit Electronics for Dummies and then getting serious. You can do major damage, start fires, distroy thousands of $$ in equipment, maybe even kill yourself by getting it wrong. We all started out knowing zip about this stuff and learned along the way so be smart... learn now and try to avoid all the mistakes I am sure I and the others in here could tell you about... if we were drunk enough to be honest that is.

Some very basic tips:
Always use very thick wire for DC runs. The smallest should be 2.5 mm and I really mean smallest, like for a GPS or small LED. 6mm is usually more like the real thing.

Use the best switches you can find. I always use Airpax simply because they are tested and then tested again for commercial aircraft and are really what they say they are, not like most "marine" switches. Trick: Check at the airport maintainance facilities. They often have "out of date" ones you can get for peanuts or a case of beers for a dozen. That has to do with the rules for aircraft not if the switches are good or not. Otherwise think 100+$ each.

Take your electrical system seriously, very seriously and it will give you years of trouble free service. Fail to take it seriously and well its your back side after all....

H/V Vega is offline   Reply With Quote

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Electrical Requirement Info? cabledave The Library 9 03-07-2009 20:07
Electrical Connections Charlie Electrical: Batteries, Generators & Solar 14 01-09-2008 22:05
Hagar Electrical zxcatamaran Electrical: Batteries, Generators & Solar 1 10-09-2007 11:12
Electrical System Charlie Electrical: Batteries, Generators & Solar 8 09-12-2006 07:32
AC Electrical Refit knottybuoyz Construction, Maintenance & Refit 15 10-11-2006 19:52

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities

Copyright 2002-2015 Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 11:45.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.