I have a 220V AC to 24V AC transformer rated at 2Amps. What size of Primary and Secondary fuse should I use?
slow-blow 2A on the output, fuses take a very long time to blow at there rating, so this is mainly to protect against hard shorts,
If you're not pulling near the rating at any time, then conventional 2A
Mains input fuse depends on the quality of the transformer, plan for 0.5A, as cheaper transformers consume some current while doing nothing.