I think
@Bluejets was asking for more specific information like:
1. What do you mean by permanent?
2. Built into the consumer unit?
3. A device for plugging into domestic outlets?
4. Testing for short circuit of what?
5. Live and neutral reversed?
6. Live and earth fault?
etc etc etc
Be more specific
EDIT: A side note, short circuits usually announce themselves by going BANG or tripping breakers.....
Martin