How many recesses of a '5-pin' socket should light a voltage tester?
Assuming you mean an IEC 60309 Plug that delivers 3-phase 230/400V power (usually a red connector), there should be power on three pins.
The largest hole is for the earth pin, and the next hole counter-clockwise is the neutral. The remaining holes should have line voltage - 230v measured to neutral or 400v measured to another line hole.
Here is a good reference for you: https://www.plugsocketmuseum.nl/IEC60309_1.html
Also, as mentioned in the comments, get yourself a proper tester for this or call an electrician to test it.