35 Amp Fuse

[Mike Armstrong]

I bought 35 amp fuses from an auto parts store to replace the Lucas fuses should they fail. Looking at a Lucas fuse a bit closer it says 35amp/17amp continuous, however the fuses I bought only say 35amp.

Doing a forum Search I read that USA fuses fail much later than Lucas fuses making the USA fuses dangerous.

Do I have to use Lucas fuses in my SV or is there a USA equivalent?

 

[Tom H]

Mike, A Lucas 35 A fuse is designed to be used in a circuit that would normally carry 17.5 A or less, and it will blow if 35 A flows continuously.

A standard US fuse rated at 35 A will carry 35 A continuously without blowing. It probably takes 70 A to blow a US 35 A fuse,

So use a 15 A US fuse to replace a Lucas 35A, and you'll probably be OK. Most failures that blow a fuse are short circuits, with resulting 30 to 100 A or more, that will easily blow just about any fuse. It's quite rare for a fault to result in a semi-large, steady, current.

The Green circuit on an Alpine feeds the parking lights, brake lights, turn signals, horn, wiper and maybe the heater and they do not take more than 10 A or so. You can easily verify this if you have an ammeter. With the engine off, tun on the parking lights and wiper, step on the brake, and beep the horn while watching the ammeter. Assuming it shows well under 15 A, use a 15A fuse. If it shows more, use a 20A fuse. Don't turn the headlights on as the current to the headlights does not go thru the fused circuit.

Tom

 

[Mike Armstrong]

Thanks Tom.