Forum Discussion

mikestock's avatar
mikestock
Explorer
Nov 30, 2016

Functional difference between JLLN and ANL type fuses

I may have accidentally, unknowingly, touched my positive lead to ground at my inverter and it blew the main 300 amp Type T, JLLN fuse. Until I'm sure this was a one time thing and no problem exists, I want to temporarily replace it with a cheaper ANL type fuse.

ANL type fuses are $2 or $3 and the JLLN sells for $30 and up. Before I put another expensive JLLN type T, I would like to temporarily use the cheaper fuse to trouble shoot.

I know they differ in appearance, but could someone explain the functional difference between the two type fuses?

9 Replies

  • mikestock's avatar
    mikestock
    Explorer
    Dec 01, 2016
    This is weird to the point of not wanting to believe it.


    It's either true or mister Simpson and mister Fluke are messing with me.

    Must have some kind of diode in each direction in line with separate fuses. Could be something about the fuse, to allow charging in one direction and output to inverter in the other.:h:?

    With the fuse replaced with a jumper everything is working.
  • PaulJ2's avatar
    PaulJ2
    Explorer
    Dec 01, 2016
    If it acts like a diode maybe it is in fact a diode. Could be there to protect the converter from reverse polarity. Is it a converter or in fact an inverter?
    Guess i'm confused.
  • road-runner's avatar
    road-runner
    Explorer III
    Nov 30, 2016
    mikestock wrote:
    One thing that is interesting: After removing the bad fuse I checked it again. It acts like a diode. I get continuity in one direction but not in the other. Never seen any fuse like this.
    This is weird to the point of not wanting to believe it.
  • mikestock's avatar
    mikestock
    Explorer
    Nov 30, 2016
    One thing that is interesting: After removing the bad fuse I checked it again. It acts like a diode. I get continuity in one direction but not in the other. Never seen any fuse like this. Can anyone explain? I replaced the fuse with a jumper just to get my psw inverter install completed and checked out. Should have proper replacement in a couple of days.

    This is definitely not a common item. Called five electrical supply houses locally and none of them had and access to acquire it.
  • mikestock's avatar
    mikestock
    Explorer
    Nov 30, 2016
    So, my plan to use the cheaper fuse temporarily while making sure there is not a hidden problem that will blow the, much more expensive, type T, 300 amp??
  • RLS7201's avatar
    RLS7201
    Explorer II
    Nov 30, 2016
    JLLN fuses are rated for 300 volts.
    ANL/CNL fuses are rated for 32 volts.
    Both are fast acting. I don't see an issue with either one on a 12 volt DC system.

    Richard

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