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Safe Handling of AC/DC Power Adapters — Desktop & Wall-Mount, Part 6: "Do Not Underestimate Low Voltage"
If you underestimate it just because it's low voltage... this article introduces safe handling methods for AC/DC power adapters — desktop & wall-mount. The sixth installment features "Never Underestimate Low Voltage." It is generally said that even low voltage of 42V can lead to serious accidents if used improperly. Please see this article for details.
Do Not Underestimate Low Voltage
At the end of last year, there was news about a fatal electric shock accident overseas where someone used a smartphone in the bathroom while it was charging. The typical output voltage of AC/DC Power Adapters — Desktop & Wall-Mount is 5V, 12V, or at most around 48V, so most people might wonder, “Can you get electrocuted by the output of an AC/DC Power Adapter — Desktop & Wall-Mount?” However, there is a phrase often heard in the electrical equipment industry: “42V is a deadly voltage.” Literally, it is a warning that “if mishandled, even 42V (low voltage) can be fatal.”
The electrocution accident mentioned earlier was not caused by the output voltage of the AC/DC Power Adapter — Desktop & Wall-Mount. Instead, the input side of the adapter was extended into the bathroom using an extension cord, and the charging smartphone was accidentally dropped into the bathtub, causing the input voltage to be applied to the water. This tragedy likely occurred because the voltage in the outlet in that country was AC220V, which is double that of Japan. With the body being wet and its resistance reduced, a high current flowed through the body. (As you know, the electric current I = voltage V ÷ resistance R, according to Ohm’s law. This means that for the same resistance, if the voltage doubles, the current doubles as well.) A similar case reportedly involved a fatal shock while using headphones connected to a charging smartphone. (In that case, a short circuit in the headphones is suspected, but just imagining current passing through the head is chilling.)
By the way, since we’re talking about electric shock, do you know why birds don’t get electrocuted while perched on power lines, but humans do when touching them? There’s a unique illustration that clearly explains this at a glance, so please refer to it. (We’d like to explain complex things this simply... m(__)m)
“Touching a power line is safe if no current flows through your body. If it does, you're out.”
This time, we’re not targeting only AC/DC Power Adapters — Desktop & Wall-Mount, but also raising awareness to avoid using devices like smartphones in the bathroom or other damp places while charging. To repeat, “42V is a deadly voltage.” For more information on electric shock, please refer to the following links and be cautious to prevent accidents.
Note 1: This discussion is strictly about low voltage. In the case of high voltage, even approaching it can affect the human body.
Note 2: According to electrical equipment technical standards, high voltage is defined as exceeding 750V for DC and 600V for AC; therefore, low voltage refers to voltages equal to or below those levels.
“About Electric Shock” (Hokkaido Electrical Safety Association)