Yellow Jacket
11-15-2007, 07:56 AM
I've noticed in a couple of threads, particularly about adding lights, that there have been recommendations made about replacing a 10 amp fuse with a 15 amp fuse.
Personally, I believe that this is a very bad idea!
Let me explain why I feel this way.
The only job a fuse has is to protect the wiring.
Any current flowing through a conductor (wire) generates heat.
The higher the current the higher the heat.
The insulation on the wire has two primary jobs.
The first is to insulate the wire from touching another conductor and creating a short circuit.
The second is to dissipate the heat generated by the current, without melting which could allow the wire to touch another conductor and cause a short circuit.
With this said, when the engineers design a circuit they anticipate the highest current that should be required and then pick the appropriate size of wire and fuse.
If they have installed a 10 amp fuse on the circuit then the wire chosen will handle 10 amps of current without over heating.
If someone replaces that 10 amp fuse with a 15 amp fuse then that wire can be subjected to 150% of the current for which it is rated. More current means more heat. More heat than the insulation is designed to dissipate will result in either melting insulation and/or an electrical fire.
I have seen electrical fires in aircraft, cars, homes and commercial buildings. It is definitely not pretty.
If you are adding lights, horns or whatever and the circuit won't handle it with the original fuse. . .install a new fused circuit! ! !
It's more work of course but it's not all that difficult. I would hate to see anyone's pride and joy suffering from an electrical fire.
Remember, the fuse's only job is to protect the wire. If it's blowing, it's doing it's job. Don't defeat it from doing it's job by just putting in a bigger fuse.
Personally, I believe that this is a very bad idea!
Let me explain why I feel this way.
The only job a fuse has is to protect the wiring.
Any current flowing through a conductor (wire) generates heat.
The higher the current the higher the heat.
The insulation on the wire has two primary jobs.
The first is to insulate the wire from touching another conductor and creating a short circuit.
The second is to dissipate the heat generated by the current, without melting which could allow the wire to touch another conductor and cause a short circuit.
With this said, when the engineers design a circuit they anticipate the highest current that should be required and then pick the appropriate size of wire and fuse.
If they have installed a 10 amp fuse on the circuit then the wire chosen will handle 10 amps of current without over heating.
If someone replaces that 10 amp fuse with a 15 amp fuse then that wire can be subjected to 150% of the current for which it is rated. More current means more heat. More heat than the insulation is designed to dissipate will result in either melting insulation and/or an electrical fire.
I have seen electrical fires in aircraft, cars, homes and commercial buildings. It is definitely not pretty.
If you are adding lights, horns or whatever and the circuit won't handle it with the original fuse. . .install a new fused circuit! ! !
It's more work of course but it's not all that difficult. I would hate to see anyone's pride and joy suffering from an electrical fire.
Remember, the fuse's only job is to protect the wire. If it's blowing, it's doing it's job. Don't defeat it from doing it's job by just putting in a bigger fuse.