VHF Power Supply

[KenMcCulloch]

A lot of marine vhf sets seem to be wired with an inline fuse at the load end of the +ve conductor, as well as a cb or fuse at the battery power distribution end. Just about to instal a new set and wondering whether the second fuse is actually needed?

 

[matthewriches]

All new installations from the panel that I do, I remove all inline fuses and just keep the circuit breaker dedicated to the VHF. Less to go wrong at sea. Although some equipment may have internal fuses to protect the device so you cannot plan for every eventuality!

 

[KenMcCulloch]

All new installations from the panel that I do, I remove all inline fuses and just keep the circuit breaker dedicated to the VHF. Less to go wrong at sea. Although some equipment may have internal fuses to protect the device so you cannot plan for every eventuality!

That’s pretty much what I thought. Thank Matthew.

 

[VicS]

A lot of marine vhf sets seem to be wired with an inline fuse at the load end of the +ve conductor, as well as a cb or fuse at the battery power distribution end. Just about to instal a new set and wondering whether the second fuse is actually needed?

The fuse close to the set protects the circuitry of the set itself. Its value is greater than the maximum current draw while transmitting but not by a huge margin.

The fuse, or circuit breaker, in the panel can be sized to protect the wiring. To avoid excessive volts drop the wiring may be fairly heavy so the fuse can be greater that the one close to the set but must of course be smaller than the max safe working current of the wiring.

If you do not have a fuse or cb at the panel you will have no protection against the effects of a fault in the wiring.

If you remove the fuse supplied by the manufacturer you will have removed the fuse that gives you protection from the effects of a fault within the set itself.. If you must remove it then be sure the panel fuse or cb rating is no higher

 

[PaulRainbow]

All new installations from the panel that I do, I remove all inline fuses and just keep the circuit breaker dedicated to the VHF. Less to go wrong at sea. Although some equipment may have internal fuses to protect the device so you cannot plan for every eventuality!

Same here, or you end up with a million different fuses behind a million different panels or bits of kit. All fuses in one or two places, all the same style is better.

 

[William_H]

The fuse close to the set protects the circuitry of the set itself. Its value is greater than the maximum current draw while transmitting but not by a huge margin.
If you remove the fuse supplied by the manufacturer you will have removed the fuse that gives you protection from the effects of a fault within the set itself.. If you must remove it then be sure the panel fuse or cb rating is no higher

Unfortunately the reality of modern electronics and servicing costs is that if the set produces an internal fault that blows the fuse it is most likely that the set would end up uneconomical to repair. So no point in protecting the internals of the set. I think the chances of an internal fire being disastrous are small. However I do agree use a CB or fuse at the distribution board appropriate to the max draw of the set on transmit around 3 amps, with connecting wire appropriate to that CB/fuse size. Unfortunately most in line fuses have a spring to press a contact onto the end of the fuse. This makes a fault quite likely in fuse contact so doing without an in line fuse can enhance reliability. good luck olewill