How to Fuse When Changing Over to LED Nav Lights

rmrstlmo

I need to replace one of my nav lights so I'm planning on switching LED lights. I have 2000 340 with the in dash small round breakers. The lights require a 1 amp fuse and the smallest breaker that I have found is 3 amp. I know I could use an inline fuse. Any other ideas? Ray

mvn

Ray, 

I'd use the 3 amp breaker and call it a day.   As long as the wiring size can handle the current,  you should be fine.   If you develop a short,  the breaker will protect the system. Like you say,  you can always add a 1 amp in line for added protection. 

Mark

Black_Diamond

If only changing one light, watch reducing the fuse. You might end up popping it from the draw from the non- LED light.  I agree with MVN on this!

mvn

Please see this post.   It's technical but very informative.   The breaker size is a function of the wire ampacity to the load. 

 

Oops....

 

http://rinkerboats.vanillaforums.com/discussion/431/american-boat-yacht-council-ac-and-dc-electrical-systems-on-boats#latest

Mark

rmrstlmo

Mark,

  Did you mean to put a link in your response?

john744

He's right about the purpose of the breaker.  In the wiring circuit, the breaker is there to prevent a fire FIRST, damage to the load second.  Since excessive current draw will create heat in the wire, too much current may cause the insulating material to melt or to ignite (depending on what it's made of).  The breakers PRIMARY purpose is to prevent this by limiting the amount of current allowed to flow in a circuit, based on the current capacity of the wire. If your concern is for the load, add a properly sized fuse close to the load itself.  This will prevent any other device in the circuit from drawing current in excess of the fuse capacity.

Short answer - Leave it alone.

mvn

rmrstlmo said:

Mark,

  Did you mean to put a link in your response?

Link added to post.