What are the safety precautions I should follow when using the HP DesignJet T520?

You should use only the power supply voltage specified on the label and never disassemble or repair the printer yourself. Always power off the printer and unplug the power cord if there is smoke, an unusual smell, unusual noise, if metal or liquid touches internal parts, during an electrical storm, or during a power failure. Only use the electrical cord supplied by HP, and never damage, cut, or repair the power cord as a damaged cord can cause fire or electric shock. (Page 10)