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RMAYNEHESS
Mar 3, 2008, 03:04 PM
I have a house built in 1935, a new 200 amp service was installed before I purchased the home. I suspect I may have a couple circuits with reverse polarity, not sure, the circuit plug in tester would not work because it is a two wire circuit all it said was open ground.
How can I check this out. Is the hot wire the one with black stripes.

hvac1000
Mar 3, 2008, 03:32 PM
Sometimes the only way to tell the hot leg is to use a meter or a 120 volt lamp and ground one wire of the lamp to a known neutral or ground source (water line usually works) and use the other wire to check the outlet to find the hot side. Many times over the years when one company upgraded a service they would confuse the neutral and hot leg because most of the time the old wires insulation was bad and they just taped the old wires with black tape instead of using white on the neutral and black on the hot leg. Becareful while doing this test since the metal box or metal back plates on the devices have no real ground. The idea is that you do not become the ground if you know what I mean.

On a side note. New 3 wire devices should not be used on two wire circuits. This can lead to a false sense of safety thinking the outlet is grounded. Two wire outlets are still available or you can block the ground prong hole on a 3 wire device. Another thing you can also do is wire a ground to all the old outlets and put a GFCI in the main circuit. This way the outlets will be safe.Check the National Electric code for more details.

Make Your Old Two-Prong Outlets Safer -- the Easy Way | Your Home | Reader's Digest (http://www.rd.com/10808/article.html)

You can extend this style of protection to other outlets by using the other contacts.