HOW TO STOP MY OPTIMA ALARM?

WE HAVE RECENTLY MOVED INTO A HOUSE WHICH HAD ALREADY INSTALLED AN OPTIMA BURGLAR ALARM,WHICH SEEMS TO WORK FINE,BUT THE PROBLEM IS THAT WHEN WE TRY TO DO OTHER ELECTIRC WORK AROUND THE HOUSE WHERE WE NEED TO TURN OFF THE ELECTRIC SUPPLY AS SOON AS WE DO THE BURGLAR ALARM ACTIVATES,TRIED REMOVING PANEL BUT THAT ACTIVATES THE TAMPER ALARM
CAN ANYONE HELP ..PLEASE..NOTE SURE OF MODEL BUT IT COULD BE THE G3