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Thread: Fan fuse

  1. #1
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    Fan fuse

    I’m fitting a SVC loom in my car and it is saying the feed to the fan is not fused. I’d have normally said that all components should be fused. Am I missing something here? Do radiator fans not need to be fused? I have two fans so was thinking a 15 amp fuse?

  2. #2
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    I have 30 amp fuse for single 16 inch two speed fan. Having it fused covers any wiring shorting and potential fire. Motors can seize and cause excessive current draw. A potential hazard eliminated.

  3. #3
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    Fuse it!, 30Amp here as well

    Jim
    GD Mk3 Jag based
    Supercharged LS1
    GD J1M

  4. #4
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    The current draw by a 16" fan on start-up is large. I had one fail, and even with the fuse there was a lot of molten plastic in the motor housing before the fuse blew. A 30A fuse is essential, and why SVC would suggest otherwise is a mystery - unless, perhaps, the fan wires they are referring to are intended to go to a fan relay with an integral 30A fuse?
    Alan

    CRC Thames Valley Regional Rep
    UK Rep for European Cobra Club (eurocobra.boards.net)
    Dax 427 DeDion - Huddart SBC 383

  5. #5
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    with regards to fusing FANs - this was the what happened to mine (25AMP) which ended up causing engine over heat, blown intake manifold gasket and the eventual rebuild of my engine




    Not saying it caused all the engine issues, but it did cause the intake gasket and therefore head skim needing etc.

    rgds
    Gary
    Conny - A Carnival Red Metallic (paint code Ref: Jag CGG/1811) Southern Roadcraft V8 ( SRV8 ) with 383ci stroker chevy.

  6. #6
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    I checked a number of 16" fans and found a running ampere draw from between 13 and 18 amps depending on the fan. In the following article, (although for AC motors, but the theory is applicable) they recommend a fuse of 175% of the running current draw under load. So for a current draw of 17 amps, a fuse of 30 amps would be appropriate. This matches up nicely with the responses you have received so far.

    https://groverelectric.com/assets/do...c%20Motors.pdf

    Now, as the start-up current can still exceed this, and the fuse will generally survive, sometimes, this stresses the fuse and it will blow after a number of start cycles. A slow-blow fuse can help with this.

    http://www.learningaboutelectronics....-blow-fuse.php
    John

    “A prudent person profits from personal experience, a wise one from the experience of others.”

  7. #7
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    Thanks guys, I have two fans so a couple of 30 amp fuses to be ordered.

    Also what size/gauge cable would you recommend?
    Last edited by Boxoftricks; 08-01-20 at 09:05 PM.

  8. #8
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    can't help on that - 18 gauge i think i used, but can't remember fully
    Conny - A Carnival Red Metallic (paint code Ref: Jag CGG/1811) Southern Roadcraft V8 ( SRV8 ) with 383ci stroker chevy.

  9. #9
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    65/030 (AKA 4.5mm²) is rated around 35A. Should do the trick.
    Cheers

    Myles D-W

  10. #10
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    There's a lot of charts on the internet if you use Google. Here's two of them, and they both yield using AWG 10 (which is for 30 Amp continuous, so it's an extremely safe choice). Your fan only draws about half of that and if it shorts out, it won't draw more than 30 amps for long before the fuse blows. No doubt one could go a lot smaller wire as the voltage drop for a fan wouldn't be significant. I'd say that Neal's suggestion of AWG 18 would be fine, but I wouldn't go smaller.




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    John

    “A prudent person profits from personal experience, a wise one from the experience of others.”

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