Hi,
i am not used to US or UK electrical systems, but if you have three wire per circuit, one that you call 'hot' (+), – and earth there is not much you could do wrong.
In any case, cut, screw out or disconnect the circuit before you do anything with it. When the fuse is on, test the circuit with one of those small electrical screwdrivers, which have a small lamp inside to indicate current.
If the fuse did not blow after you wired it, you must have done something right
Anyway, are you sure the circuit you got the electricity from, is working itself ?
Then (please do not beat me) just to make sure, you DID remove the insulation around the wire, before connecting it either via snap-in, or screwing it tight ?
You could also post a picture ..
Greetings,
Catfish