If unsure or nervous around electricity, just ground the segment you are working on first. But the parts that should make you extra cautious have wires with a

If unsure or nervous around electricity, just ground the segment you are working on first. But the parts that should make you extra cautious have wires with a lot of insulation so they look thick. those are the 20Kv bits. you also will want to take the time to drain any big capacitors. you can just short the leads or if you are feeling conscientious(and don't like sparks) drain them with a resister(100kohms or so) between the leads.