A brand new 80 Amp or 100 Amp main fuse for your 1990-2005 Mazda Miata.

Why would you need one of these?
Got a sudden strange electrical issue?
Did you get a jump start and hook up the battery cables backwards?
Installed the battery cables on the wrong terminals by accident and now it won't start?
No start condition?

Well, these are all signs that your main fuse may be blown.
It's not the worst thing in the world.
I mean, it did save the life of your ECU by blowing the main fuse.
It's a good built-in safety failure point, to be honest.

Factory Main fuse size for 90-97 Miata is 80 Amp (note, a 100 Amp fuse will fit, if you choose to increase capacity)
Factory Main fuse size for 99-05 Miata is 100 Amp. (note, the 80 Amp fuse will fit if you want a smaller capacity fuse)

All that said, you should keep a spare main fuse and 10mm wrench or socket in your glovebox.
Click here to order one and check off that box on the "need to have" spare parts list.
It'll be a rough day when you need one of these.
Might as well plan for it on a day that's much better.
Order one today and put your mind at ease.

Side thought....
As I write this, I contemplate adding a "include 10mm wrench" option variant for purchase...

Back on topic.
New in box main fuses available here.
This is the easiest way to avoid that future pain.
Put that little worry to work and buy one of these new Main fuses for your Miata.
Your future self will thank you ... and MrMiataParts too ;)