Re-wiring helm

[Ridewright79]

I have a few questions in regards to fuse sizes. I am re-wiring the helm on my 95 stingray 698zp due to the fuse panel tabs breaking and also cleaning up the rigged up wiring the previous owner did. I had all my lights go out in the middle of the night while underway. Most of the fuses I have done some research and found what I need for the bilge pump, blower and most of the accessories but can't find much regarding the main ignition fuse. I was thinking somewhere around 20 amps does that sound about right? I am installing a blue sea fuse panel and all new power and ground wire. Also soldering and heat shrinking all connections.

 

[Silvertip]

Re: Re-wiring helm

In general fuse size should be determined by the ampacity of the wiring.

Not necessarily. The MAXIMUM fuse size is based on the wire gauge and should not be exceeded. Since 16 gauge wire is used in most accessory circuits there is no need to install 10 amp fuses if a device like a fish finder draws only an amp or two. Look at the wiring going of the fuse panel of your car. Most of those wires are the same size yet the fuse sizes vary. Why try to make a device smoke instead of just popping a fuse when its current draw is obviously above normal indicating a problem. Yes -- the fuse protects the wire. But again, why fuse it at 10 amps when the device draws much less than that. If the fuse pops the device is probably junk anyway.

 

[Ridewright79]

Re: Re-wiring helm

In general fuse size should be determined by the ampacity of the wiring.

That is only true for maximum load on the wire and calculated by distance due to voltage drop.

 

[Ridewright79]

Re: Re-wiring helm

Like I said previously I am re-wiring from my bus blocks to a new fuse panel. Then all new power supply and ground wires using 14awg wire. I am not curtain what the fuse rating should be for the ignition circuit itself. All the acc components have max rating for amp draw so calculating the fuse size is easy. I just can't find info regarding the ignition fuse size.

 

[Don S]

Re: Re-wiring helm

Mercruiser uses a 20A fuse on the Red/purple wire just before the ignition switch.


View attachment inst wiring.pdf

 

[Ridewright79]

Re: Re-wiring helm

Mercruiser uses a 20A fuse on the Red/purple wire just before the ignition switch.




View attachment 184248

Thank you again Don S. that is the info I was looking for. I figured it was 20 but wanted to make sure.