ATO vs. ATC blade fuses: what's the diff?

[Alan Georges]

OK, the O & C stand for Open and Closed, and you can see openings in the O-type.  They're physically the same size, they fit in the same fuse blocks.  To that degree they're interchangeable.

But what's the difference in their function and purpose?  Is one better than the other in certain applications?

Odd question, I know.  I've been using whatever happens to be on a store shelf without worrying about it and nothing bad's happened, but it would be good to know if there are any pitfalls here.

[FreeLancer]

That’s a good question.

[armymars]

  In my power distribution box I use the ones with the pretty led's that light up when they blow.   

[Carl]

  The ATO and ATC are the same...except the ATO is open at the top of the blades so it can be tested while in circuit (little slots leave access to the top of each blade )
\
If there is an advantage ,it is in possible wet conditions causing corrosion or degrading of the fuse element.

EDIT...here is the official word:

The regular-sized ATC fuse is more common than the ATO. The ATC has a fuse element that is closed (hence the “C” in the code) inside the plastic housing, sealing it from the environment to prevent corrosion from developing. The ATO fuse is open on the bottom, exposing the fuse element between the blades.

[Alan Georges]

So that's it.  ATO pro: open for test probes.  ATC pro: sealed against corrosion.  And otherwise completely interchangeable.

Thanks Carl!

[Carl]

So that's it.  ATO pro: open for test probes.  ATC pro: sealed against corrosion.  And otherwise completely interchangeable.

Thanks Carl!

My dad pulled me aside and told me that ,and some gross stuff about girls when I was 12 years old 

[FreeLancer]

Makes sense.

[Alan Georges]

My dad pulled me aside and told me that ,and some gross stuff about girls when I was 12 years old 

Oh man, that's heavy...

[Carl]

Oh man, that's heavy...

 I was just a kid and cooties were the worst thing that could happen.

[Mr. Bill]

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