Voltage question for some electronics repairs techs...
After feeling electricity when connecting two cable wires via a coupler, I traced the source back to my Scientific Atlanta 8300HD cable box. This cable box has no ground prong. When all wires expect the power are disconnected, my meters reads 48 V AC from the case to ground. For ground, used both my hot water base board and the neutral and ground from the receptical. The outlet polarity is not reversed.
When touch ground and the box with my hands, I can intermittently feel slight tingling, about the strength of a dying 9 V on the tongue.
I've also verified the cable wire is grounded. When it is connected to the box, the voltage on the case of course disappears. Obviously it cannot source much current, since this is effectively shorting a voltage source to ground.
The cable company has had two other boxes out, and both have the same symptoms.
Am I missing something here? This cannot be normal. For a two pronged appliance, I assume the case should be electrically isolated from both the hot and the neutral. Does this sound right?
Any ideas or info would be appreciated. Thanks.
DMT