I'm a professional electrician. Basically provide electrical services and solves electrical problems: common electrical problems that can cause power disruptions and fire are : earth fault, electrical installation without earthing system, burnt wires in an electrical system/consumer units/distribution boards, loose contacts that when left for a long time will eat up your prepaid unit and cause electrical fire from sparks, electrical leakage problems, faulty electrical equipment, outdated electrical gadgets and general electrical problems left unchecked. I recommend preventative maintenance for electrical gadgets; especially air conditioners, water heaters, kettles, microwaves, refrigerators, consumer units/Distribution Boards and most importantly houses without earthing systems or has an earth resistance value of 10 mega ohms or more to install Residual Current Device (RCD) for their own safety and protect their property.