I just wanted to check if my thinking was correct on this.
I have a victron inverter in which I have recently manage to blow something. it does AC to DC and DC to AC. I bought a new DC fuse but this made no difference.
With the AC fuse I just decided to test it - and put it in a 12 volt DC circuit with an LED, the LED turn on. Am I right in thinking that this fuse is not blown or is there something else I should be taking into consideration - as I have not put it in a AC circuit.?

 

All you need is a simply continuity check to determine if a fuse is blown or not..
ac or dc won't matter..
If it turned on its fine.

 

LED is On, the fuse is not blown.

 

Not always true. I have seen fuses which passed continuity test and opened up after turn on and then passed continuity test again. Only way to check is run some current through it. Maybe 80% of rated amperage

 

Thank you for this info. I had used DC as it was safe and I had only done DC electrical type things before. but I found a way doctoring an AC plug and put it in there it happily turned on a light but I did not try it on anything stronger. The fuse is twenty AMPS should I try it on an electrical heater 3kw?

 

The fuse is fine..