Wiring Question

[jimmcgee]

I’m going to install a 12v TV/DVD and rewire my stereo this week on my 95 Catalina 30; wiring both to a circuit direct to the battery so I don’t have to rescan stations every time I get on the boat (boat is kept in a marina other than occasional overnights at anchor).

The stereo (Sony car stereo) is pre-wired with a fused line to run to the battery directly (P.O. didn't connect when he installed the stereo). I looked at the specs on the 110v adapter for the TV. Its output is 12vdc/5amps. So the plan is to add a 12vdc plug for the TV in an outlet box on the forward bulkhead, with a 5amp breaker in the box so the outlet will be switched. Then run a line from the outlet box to the battery with a Anchor 5amp slow blow inline fuse where it connects to the battery post.

Why create a switched 12v outlet rather hardwire it? I want the option of switching it off if I’m trying to conserve power or troubleshoot a problem; and the outlet gives me a place to plug in the extension cord for a spotlight at night.

My question is am I missing anything from a safety perspective? I want to breaker to trip before blowing the fuse. Is there any reason NOT to use a slow blow marine fuse in this application?

Thanks,
Jim

 

[jimmcgee]

Fuse question

The other wiring thread seems to be getting all the attention.

Any thoughts on my fuse question? Anyone?

 

[Old Skool Neil]

Jim, you're right. Those other threads are getting all the action.

As long as you're providing overcurrent protection to the direct wired circuit you're satisfying the intent. Cluttering up the battery posts with various wires is considered bad form however.

Regarding the use of a slo-blow fuse, it will give the radio a full dose of excessive current (beyond 5 amps) for a greater length of time than a fast acting fuse, possibly damaging the radio. Circuit breakers are inverse time delay too (at least the thermal breakers are, not sure about the magnetic ones).

You need to decide what's more important, avoiding the nuisance of changing fuses or providing the best protection to the radio that you can. Note that the radio was no doubt shipped with a fast acting fuse from the factory. Maybe they're on to something?

 

[jimmcgee]

Cluttering up the battery posts with various wires is considered bad form however.

Neil, so what is best practice? I'd rather do it once and do it right.

 

[Old Skool Neil]

You might want to connect the radio's sentinel circuit to the hot post on the battery switch or you may want to add a hot buss for unswitched (and fused or otherwise protected) circuits such as this sentinel, the bilge pump or a fume sniffer.

The hot buss would be my preference, keeps the battery switch terminals uncluttered and in my opinion is a more professional installation.

 

[jimmcgee]

Makes sense. Thanks Neil.