Signese

1) A desk light, although it doesn't really look like one.

2) Twist it or wiggle it.

3) It might 'leak' electricity! Sounds so harmless, but actually so lethal.

I hope that metal frame is earthed - I mean, apart from through your body, especially if you've rewired the fusebox with solid copper to stop the power cutting out as soon as you switch on more than three electrical items.

1) What is the sign on?

looks to be on a piece of galvanized conduit

2) What should you not do?

wriggle/wiggle the table lamp

3) What is there a danger of if you do?

leakage of electricity