50 amp fuse goes out ???

old bird

Petty Officer 3rd Class
Joined
Mar 22, 2009
Messages
82
88 Bayliner capri
2.3 OMC cobra o.d

50 amp inline fuse gets hot and falls apart, does not blow ????
what/where to look.
Thanks Larry
 

wire2

Lieutenant Commander
Joined
Jun 25, 2007
Messages
1,584
Re: 50 amp fuse goes out ???

Is the fuse tight in the holder? If not, the end connections will heat up, eventually causing the alloy link to melt. Check across the connections with a voltmeter. There should not be more than a few milivolts drop across it.
 

Howard Sterndrive

Rear Admiral
Joined
Nov 5, 2008
Messages
4,603
Re: 50 amp fuse goes out ???

when a fuse melts it can also mean a consistent heavy overload, as opposed to blowing from a sudden overload or short to ground where you see a black spot on the glass.
 

wire2

Lieutenant Commander
Joined
Jun 25, 2007
Messages
1,584
Re: 50 amp fuse goes out ???

You're quite right Howard. I did consider that he may have ~45 amps running to somewhere, but that's 600 watts of power, it would likely manifest itself somehow. Ideally, an ammeter would be used to measure actual current but few boat owners have one capable of 50 amps.
Plus I've seen a few 15 amp fuses melt with only 8-10 amps load, just because they were loose.
 
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