Are there any chances it may damage my computer?
closed as off-topic by PlasmaHH, Dmitry Grigoryev, PeterJ, Peter Smith, Ricardo May 12 '16 at 12:20
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "Questions on the use of electronic devices are off-topic as this site is intended specifically for questions on electronics design." – PlasmaHH, PeterJ, Peter Smith, Ricardo
it came with 3 prong power cord but i needed to extend the cable and i had this 2 prong extension cord so i plugged in my 3 prong cable into 2 prong... is that safe?
It is generally unsafe not to earth equipment which was designed to be earthed e.g. a typical mains-powered desktop computer, as in your question.
This is because, in the event of a fault which causes any exposed metal to become "live", the fuse will not blow, since there will be no large current flowing via that (now missing) protective earth wire. :-( Therefore you could be electrocuted by touching the (now "live") metal case and having any other current path (e.g. through your feet, or other hand etc.) to earth.
Based on your description, please do not extend the 3-core mains cable to your desktop computer, with a non-earthed 2-core cable.
Your chassis will float to half the mains voltage, 115 Vac in 230 Vac countries and 55 Vac in 110 Vac countries, due to the Y-caps between N-GND-L in the power supply of your computer. This may seem harmful but the current though them are limited by goverment standards to 750 uA. This can hurt you, but not enough to kill you. Your EMI will be very compromised too and you may experience excessive 50/60 Hz hum in audio. Whenever I don't have access to earth, I do it like you and run without but please pay attention/measure when you need to connect things like computer -> stereo/TV/antenna, where you may short this 115 V to anouther local or real ground.