What 36 sedan says is true. I watched a fellow Marine get thrown on his butt by getting too close to the anode on a high power diode tube in a piece of radar gear. Burnt a hole in his finger as well.
I got too close to the contacts on the rotary switch that controls the cabin lights on an early DC-9 with about the same results. My finger hurt worse than when I got it caught in the bolt action of an M-1 Garand in boot camp.
During a high voltage shut down test on a 27in TV when I worked at Zenith the anode lead came off the tube and landed on the yoke and that caused a small fire. Approx. 27,000 volts at the anode.
Conclusion: If you're not sure of what you're doing electrically, let someone do it who is and save yourself a lot of grief and headache.