Quote
The colouring scheme matches the colours typical of Edison plug fuses;
Blue=15A
Red=20A
Green=30A
Grey=40A
Above that black handles are used.

If you have found a 40A Edison plug fuse, I want it for my collection. [Linked Image]

Blue, red, and green are correct, and several breaker manufacturers have used these colors for their handles. I'm remembering Bryant before their breaker business was bought by Cutler-Hammer.