The valve which is spluttering water is the anti-vacuum valve..... designed to let air into the boiler when it cools down (to prevent a vacuum) and to let air out as it heats up so the boiler is full of steam - not air. Air provides false pressure and you wont be able to texture milk correctly if air is present.
It will spit and sputter a little (it is cool.... steam condenses on it producing water which is blown out). I wouldnt expect the water to go onto the electrical connections - that is bad, bad, bad!!! *:o :-[
The pump produces 9 bars (if correctly adjusted).... tamp too hard or use a fine grind and 9 bars cant penetrate it.... so no extraction - perfectly normal and wont harm the machine (it has an over pressure valve to protect it)
The anti-vacuum valve mentioned above regularly fails on most machines and sticks closed...... (well at least you wouldnt get spluttering water if that happened)... However you can then get a vacuum (which can draw milk etc from the wand back into the boiler) and false pressure at start up. *That is why if you attend a commercial machine workshop (and you should!) you will be told to always open the steam wand at shut down and leave it open until a good head of steam is coming out when it is warming up.
And also never - never ever, leave the wand soaking in a cleaning solution, milky water or anything else. This can get sucked into the boiler and contaminate the water...... :P :P
All this - and more - will be explained if you attend a workshop...... *;)