Always use the size of fuse recommended by the manufacturer of your gadget. Fuses do not blow without a reason. When replacing a blown fuse, get the fault fixed before replacing fuse.

You should not touch these fuses unless you are a qualified electrician. These are often old units and your electrician may suggest upgrading to safer RCB replacements. Tampering with these could have implications and you can expect insurance problems if you get it wrong!

Many manufacturers use colour codes to indicate the trip rating. However, they usually "invent" their own colour codes - thus RCB colours will not reliably indicate their rating. For this reason, it is not possible to offer a reliable RCB colour guide.

Most RCB "fuses" have a switch which shuts off power when an electrical safety issue is detected. Once you have repaired the fault (e.g. unplugged a faulty appliance,) you should be able to manually put the swictch back into the ON position. A switch that refuses to reset is a clear warning that the power circuit is still unsafe.

Always check the rating written on a fuse because you occassionally encounter "wrong colour" fuses. There is more than one type of blade fuse.