Solving with electrical knowledge
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Dear electrical experts, I have encountered a problem and would appreciate your guidance. There is a socket on the wall at home, intended for charging a phone; it seemed to have no power. After opening it, I used a voltage tester to check the two wires – the light on the tester lit up for the red wire, but not for the blue wire. When I connected the phone charger, the phone did not show any indication that it was charging. Once again, using the voltage tester on those two wires, neither light turned on. What is the reason for this?
A lit red test pen light does not necessarily mean there is electricity present; it’s best to use a multimeter for measurement!
The light on the pen might only be at 5V, and 5V is not enough to power a phone charger
It’s likely a poor connection; check all the incoming and outgoing wires in the distribution box to see if any are loose. It’s best to tighten everything once more, and also remove the outlet panels that have no power supply and try tightening those as well (it’s likely that the panels were compressed while the charger was connected, causing the wires to become loose; the BV wires commonly used in home installations are prone to such problems, so BVR wires with multiple conductors should be used instead). If this doesn’t work either (the multimeter isn’t very useful in such cases, as it’s impossible to determine whether there are any connections within the wires; a slightly loose connection cannot be detected by a multimeter), then turn off all the circuit breakers in the electrical panel, disconnect the ground and neutral wires, unplug all electrical devices, and use an insulation tester to check the insulation.
The loose connector pierced another wire
A small light turning on doesn’t mean there’s a charge; why does it light up? Is it due to induced electricity?
It’s so troublesome. First, check if it’s due to the thread end. If not, then just don’t use it; you can rewind the thread again when you get the chance.
Ahah, this renowned sea friend! It’s very simple – a voltage tester can only determine whether there is electricity or not; it cannot indicate the quality of the wiring! Based on your description, there should be no problem with the live wire of the socket, as the indicator light came on after the test pen was connected to the ground through the human body ； The neutral wire cannot pass the test with a voltage tester. Even though you have plugged in the charger, if the neutral wire is broken, the connections are loose, or there is poor contact, a circuit cannot be formed. Without a circuit, there can be no current, and thus no light will turn on! It’s estimated that checking the neutral wire of the socket will solve the problem!
If the N-line test pen does not light up, it indicates that there is no problem; if the phase line lights up when tested with a test pen, it might be due to induced electricity, and in most such cases the phase line is not properly connected!