We've been directed to a Safety Guide created by Tatiana Crisan for those building their own personal CNC machine. While a CNC machine is by no means a 3D printer, many of the safety guidelines portrayed are totally applicable for those building personal 3D printers.
Yes, reading these points may seem obvious and even monotonous, but most are applicable or have analogous points in 3D printing. You probably know most or all of them already. But the point of a safety guide is to DO THEM. It's just too easy to forget; a safety guide provides the opportunity to remind yourself of the necessary steps and builds good habits.
Read the steps and consider them when working on your machine.
Be safe and don't break anything - especially yourself.
Via RS Online