resetable fuses

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Matata

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We are tidying up the electric circuit panel for our sigma and next on our list of to do's are the resettable fuses. These are a simple push to make and you can push them in again and release to turn the circuit off. They now have a tendency to not stay in , not because of overload but because of age. The push button has a body behind it about the size of a small match box. 12v around 5amp. illuminated would be posh but not necessary.There is about 12 in all. We want good quality that will survive the environment....suggestions on a blank envelope and a virtual pint for the winner. Ta Nik
 
Buy the best you can afford, resetaable fuses don't seem to last forever but better ones last longer. If you can afford it get a few extra as spares, or failing that some rubberised inline blade fuse holders as an emergency backup. If you fit the correct terminals to them and suffer a resetable fuse failure you can effect a temp repair with that.
 
Could someone explain the advantage of a resettable fuse over a cb or a MOSFET based current controller please? Im not sure why anyone would fit a fuse to anything other than a very high load.
 
Matata said:
We are tidying up the electric circuit panel for our sigma and next on our list of to do's are the resettable fuses. These are a simple push to make and you can push them in again and release to turn the circuit off. They now have a tendency to not stay in , not because of overload but because of age. The push button has a body behind it about the size of a small match box. 12v around 5amp. illuminated would be posh but not necessary.There is about 12 in all. We want good quality that will survive the environment....suggestions on a blank envelope and a virtual pint for the winner. Ta Nik
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Love the term resettable fuse.... If only I could buy one!

Just a slight fred drift

The problem with most circuit breakers is people will continue adding additional loads to circuits without increasing the size of the breaker and probably the cable that is feeding it.

We typically will size a circuit breaker in our industrial control panels to the rated current of the circuit plus 25% then select the size of standard circuit breaker that is either the same as or the "next one up" (They are not available in unitary amp steps!) Also depending on the circuit one may use different "trip class characteristics of breaker. Breakers rated A B C D are chosen to reflect the actual maximum current and duration that the circuit may pull regularly. This is usually the start up current or in rush current which can be very significant and can be 10 times or more the rated operating current of the circuit you are protecting.

If you have reset the "Resettable Fuse" on your shore power breaker more than a couple of times. It is probably only capable of operating at less than 50% or less than its original design capacity. This explains why you usually end up having to turn off the electric oil fired heater if you want to boil the kettle at lots of visiting berths in marinas!

So remember each time you reset your fuses you are effectively replacing it with a smaller one!

 
My boat has ETA breakers in the switch panel, about 20 in total, various amperages from 5 to 20, but I'd have to check that, and also the type designation.
TBH, I've never been sure that they are really made for on/off switching duty, but that's how they are used. In the 14 years I've owned the boat, plus previous ownership, some must have been operated hundreds of times but only one has needed replacing because it would no longer latch in. Fortunate, as they're quite expensive.
 
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