Wawa:
Between six wires and a common ground?
No, between any wire and any other wire.
Wawa:
Do you use internal pull up or external resistors. What value?
Since I have to determine which two wires are in contact, each Arduino analog input has a voltage divider of total 1 MOhm <== EDIT: this is mistake, sorry, the total divider resistance is about 15 k Ohm
Wawa:
What sort of wire. Shielded, twisted?
Two simple 3-conductor signal cables. No shielding, to twisting or braiding.
Grumpy_Mike:
You are not going to affect anything in regard to your sample rate, they are way too slow.
Unfortunately I need to catch some very brief contacts, of the order of 10 microseconds