Mains tester screwdriver

mik3

Joined Feb 4, 2008
4,843
Its just a high resistance resistor in series with a neon lamp. When you touch the bit of the screwdriver on the hot (live) wire current passes through the resistor, the neon lamp and your body down to ground and the neon lamp illuminates. You dont get shocked by the current because its very small. Because the current increases with voltage if you exceed the voltage rating of the device, its written on it, you will get shocked.
 

Bernard

Joined Aug 7, 2008
5,788
We had a buried conduit with two exposed ends,no identification in breaker panel , hot or cold and not a meter around except for my trusty pocket screwdriver. It was still HOT. I still have most of a working driver.
 

beenthere

Joined Apr 20, 2004
15,819
You should see the notch in my wire stripper that came from cutting a pair of live wires. Sure do believe in insulated handles.
 
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