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Safe Handling of AC/DC Power Adapter Part 6 "Do Not Underestimate Low Voltage"
If you underestimate it just because it is low voltage..., we introduce the safe handling of AC/DC Power Adapter. The 6th installment features "Do Not Underestimate Low Voltage." It is said that even the commonly used low voltage of 42V can lead to serious accidents if used improperly. Please read this article for more details.
Do Not Underestimate Low Voltage
At the end of last year, there was news overseas of a fatal electric shock accident caused by using a smartphone in the bathroom while it was charging. The output voltage of a typical AC/DC Power Adapter is about 5V or 12V, and at most around 48V, so many people may wonder, "Can you really get electrocuted by the output voltage of an AC/DC Power Adapter?" However, there is a commonly used phrase in the electrical equipment industry: "42V is the deadly voltage (42V)." As the words imply, it serves as a warning that if used improperly, even 42V (low voltage) can be fatal.
The fatal accident mentioned above was not caused by the output voltage of the AC/DC Power Adapter. Instead, an extension cable was used to run the input side of the AC/DC Power Adapter into the bathroom, and the smartphone being charged was accidentally dropped into the bathtub, causing the input voltage to be applied to the bathwater. This appears to have led to the tragedy. The accident occurred in a country where the outlet voltage is AC220V, meaning twice Japan's voltage was applied to a wet body with reduced resistance, resulting in a large current flowing through the body. (As you may recall, according to Ohm's Law, current (I) = voltage (V) ÷ resistance (R)... in other words, for the same resistance, if the voltage doubles, the current also doubles.) In a similar case, there have been fatal electric shock accidents involving the use of headphones connected to a smartphone while it was charging. (In such cases, insulation failure of the headphones is suspected, and just thinking about current flowing through the head is chilling.)
By the way, while we are on the topic of electric shock, do you know why birds do not get electrocuted when perched on power lines, but people do when they touch them? There was a unique illustration that explains this at a glance, so please take a look for reference. (I wish difficult topics could always be explained this simply... m(__)m)
"If no current flows through your body when you touch a power line, you're safe; if it does, you're out."
This time, the point is not limited to AC/DC Power Adapter. Please be careful not to use Products such as smartphones in wet places like bathrooms while charging. To repeat, "42V is the deadly voltage." For more information about electric shock, please refer to the links below and take precautions to prevent electric shock accidents.
Note 1: This discussion concerns low voltage only. With high voltage, simply approaching it may affect the human body.
Note 2: According to the Technical Standards for Electrical Installations, high voltage is defined as exceeding 750V for direct current and 600V for alternating current; therefore, low voltage refers to voltages at or below these values.
"About Electric Shock" (Hokkaido Electrical Safety Association)