Still con-fused about fuses

[Member 10617]

Right. My Triumph handbook states that there should be 35 amp fuses on both sides.

However, when I got the car, there was a Buss 50 amp fuse in the left side and a Buss 20 amp fuse in the right side! I took them out and began this process of trying to discover which fuses are appropriate. I have installed Moss (Lucas type) 35 amp fuses on both sides, with the same for the spares. If, by chance, the RH fuse blows because of an overload (all the normal items plus my electric fan going at one time), I'll just put in a new 35 amp fuse. Some day I'll have the fan fused separately.... or perhaps, as suggested, run it through the LH side.

I have a feeling that there are many people who don't realize that the British system and the American system of fuses are different[... and it's an important difference. As one site I have found has pointed out: "As an example, the 35 Amp fuse called out for many 1950's/60's/70's vintage Britcars... is roughly equivalent to a US-spec BUSS AGC 17 Amp fuse. Install a US 35 Amp fuse in your LBC fuse box and the wiring harness will melt down before the fuse blows.... The US system rates the fuse based on the continuous load it can handle for a specified period of time w/o blowing, whilst the British system expresses the load at which the fuse will immediately blow."

Even though these cars are relatively simple -- compared with modern cars -- they are serious machines that demand careful attention and a lot of knowledge. Which makes this Forum invaluable.

 

[mrv8q]

So, just to muddle the waters a bit, as Geo and Randall know, a 35A and 50A British-standard fuse is called for. P36 of the Instruction book:

Yes, but that is a fairly early edition. Later editions show both fuses as 35 amps. I can't lay my hands on my 4th ed at the moment, but both 5th & 6th show 2x35.

Wow, thanks for pointing that out, Randall. I had no idea! So much for edition 4! Off to see if 2X35 Fuses will work OK in my previous 50+35 car...

 

[Member 10617]

I've settled down with 2x35 amp, even with my new electric fan working, and I've had no problems (so far). Lesson learned: don't let a person not familiar with Britsh cars and British electrical systems cars put American fuses in.