Security of Tenure

During my job interview as a driver, it was made clear to me that I will be asked to perform basic office maintenance duties like changing bulbs or broken door knobs from time to time which was OK with me. I was hired as a temporary employee (driver/messenger/maintenance) for a this local company in Feb 2014. On Sept of the same year I was already a probationary employee. It will be my 1st year with the company on the 6th of Feb and until yesterday I was only being reviewed on driving/delivery duties. No other duties was assigned to me. Yesterday, I was being asked to fix some office fixtures like lighting and phone lines. Lightings fixtures were not basic maintenance as they require checking and changing of electric lines, ballast and stuff. This is not basic and I think this should be done by someone who is certified to do this. This is unsafe for me and the company as a whole if I will do it with no knowledge. Will this have an effect on my employment? As an employee of one year, do I have the right to security of tenure?

Thanks.