Radio Positive In-Line Fuse

[Cajundave10]

I just installed a new stereo head unit in my boat. The positive connection has an inline glass fuse. I blow it when the music is turned up loud. The radio itself has a fuse on it. Do I need the inline fuse? My 6" marine speakers are rated for 75 watts RMS...My radio is only rated for 50 watts or less RMS. I should be safe removing the fuse don't you all think?

 

[Grandad]

I'm not an electronics guru, but I think maybe that a 75 watt speaker will allow more power>current to flow than what your 50 watt stereo can output, overloading it. It's never wise to eliminate a fuse because it keeps blowing. - Grandad

 

[Cajundave10]

I know what you are saying but the stereo is only capable of outputting 50 watts per channel. I could have 500 watt speakers and just because I have those doesn't mean that my head unit is capable of pushing that much. I still believe the fuse in the stereo protects me from any surge of power and subsequent damage to my stereo.

 

[Alumarine]

The inline fuse, did it come with the head unit? What size is the fuse?

 

[Cajundave10]

No it didn't come with the head unit

I think the 10Amp 250v

 

[gm280]

No it didn't come with the head unit

I think the 10Amp 250v

There's your problem. You are using a 10 amp fuse in a circuit that is capable of needing more amps. So that IS the reason it blows when you turn up the radio. If you used the proper size wire for at least a 20 amp or more circuit, I would put a 15 amp fuse in and happy boating. But if you are on the edge of capable wire size, you are seriously looking for a possible fire if the wire heats up before the fuse blows. Your radio amp is capable of 55 watts per channel and that is probably an RMS rating and not peak to peak. And so you are drawing more current them 10 amps. 55 watts times two equals 110 watts and that is RMS and certainly not PP wattage. So figure double that wattage and you have 220 watts. Now divide that by 12 volts and see your problem. JMHO!

 

[wrench 3]

The fuse at the radio is protecting the unit but the fuse at the source is protecting the wiring. If the wire is 14 gauge it will handle 20amps. 18 gauge 15amps.