[BARacer]

I was so worried it was going to be a simple one line answer!

Thank you.

[CMOTD]

Excellent 'How to' Andy. Perhaps Jason would like to add it to the home page as a permanent resource.


A couple of questions:

1) How does the fuse protect the controller? As it is fitted between the power supply and socket any overload/short circuit is going to hit the controller first before it reaches the fuse.

2) Why 5 amp? Wouldn't a lower rating be safer. Home set slot cars would hardly pull 2 amps even at start up.

[woodcote]

Thanks Brian.

It is always safe practice to place the fuse after the power enters an electrical circuit. This video explains it well...



Of course, there’s nothing wrong with also adding a fuse in the controller handle. Most US controllers have fuses fitted as their crocodile plug hook-ups are notoriously unsafe and often not protected with a fuse.

I do routinely use a 5 amp quick blow fuse at the input to each controller box on my layouts. These are to protect against a fault anywhere in the circuit and avoid any collateral damage. My controllers are all rated above 5 amps - or have their own fuse - and all the other components in the circuit are also rated at 5 amps or more. That’s why a 5 amp fuse works for me. I could use a 2 amp fuse, but it wouldn’t offer any more protection to my components. And I do use some hot motors which might blow a 2 amp fuse (the power supplies I use are 5 amps and 8 amps). 

Exactly what amp rating someone uses is up to them - the 20mm fuse holder is very versatile. The two important factors are that 1) the fuse is rated less than the lowest rated component in the circuit and 2) it is a quick blow fuse.

[BARacer]

Have ordered the parts to make two boxes for my rally tracks.

I have some spare inline fuse holders, so will be going down that route for my first attempts.