Incorrect colour of wire
While working in Rathfarnham and Ballybrack recently, I can across instances where someone had used yellow and green wire as a live wire. This is extremely dangerous as most people will assume the yellow and green wire is earth (which it should be). This is a potential trap that could kill or hurt someone.
If you have an electrician working in your home ensure he/she is registered with SAFE ELECTRIC. They should be able to issue you with a certificate for the work they complete.