1.this model is through the capacitor step-down voltage, let the high voltage reduce to low voltage provides 5VDC power supply to the thermometer,
distinguish to connect L N wire, as long as the connect correct of L and N wire, there is no problem.
2. If the L/N wire connect reversed, it will not appear electric leakage, because all the sensors been tested before release the factory,
and we do puncture test, 3750V 3seconds. the insulation between the sensor wire and sensor metal shell is good, does not appear electric leakage
3. Use the electric test pencil then red lights: the voltage of sensor metal shell is false voltage, that is not electric leakage voltage. Because the sensor wire
is near to the metal shell, this voltage is very low, less than 12V, so the test pencil light is very weak. It's safe, don't worry.