Engine fan

[NigelBush]

I have a 30 amp fuse for my single engine fan , l wonder if this is too higher rating. Can anyone tell me what value they use. Many thanks.

[Patrick]

The amount of power it pulls will depend on the fan model - if it shows a model number you can probably check with the manufacturer. If you can borrow a clamp meter from someone you'd be able to measure it.

You could do it with a normal multimeter if it were rated high enough (many wont be more than 10a or 20a) or with a DC shunt that lets you measure a small current and calculate what the actual larger current is (its been way too long since I lasted used one to remember the specifics though).

Ideally the fuse should be rated lower than the cable thickness/length you are using, but higher than the device - ie fuse pop before cable melts in the case of a short.

[dave_kitson]

Very dependant on make/model/size. An ordinary fan may pull as little as 5amp, but a heavy duty Kenlowe can pull as much as 24amp. Also the starting current will be considerably more than the running current, and there is the possibility of other electrical items running off the same fuse. There is loads of info on fans in the Europa and Car Builder catalogues incl current requirements. If all else fails, you could try substituting lower value fuses, until one blows, then go for a higher value - a few fuses won't cost the earth! Dave

[greyV8pete]

Use a slow blow type fuse too as they cope better with the high start up current. They can be recognised on a blade fuse by looking through the clear plastic. The slow blow type has a longer U shaped fuse link between the two blade contacts.

[NigelBush]

Many thanks

[HairyDave]

Use a relay to take the main current. It saves the switch.