Checked out a newly wired pre fabbed house.

When light switches are turned off found about 30 volts still on the line has anyone seen this? This switch is supposed to be completey open, can't be a bad ground or neutral,switch is supposed to be open.

Hello Tony
Try checking the circuit when there is a "load" applied,(ie a light bulb)my guess is you will find that your 30 volts has dropped off to "0".
It is possible that high humidity is causing a small leakage across the switch.
Did you find the leakage on more than one circuit? If so suspect the humidity,if it is only one circuit suspect the switch.
Good luck

Tony,
Are you using a digital meter? Is the hot and the switch leg in the same run of NM cable? If so the reading is normal. Is there a load connected to the switch?
Don