Reasoning

In North American electrical systems, the wide (long) prong on a plug is neutral, while the narrow (short) prong is hot (live). This design is part of a safety standard called polarization.

Here’s why this matters:

• The hot wire carries current from the power source to the device.

• The neutral wire carries current back to the source and is typically at or near ground potential.

By making the neutral prong longer (or wider) and thus controlling which way a plug can be inserted (polarized plug), we ensure:

1. The hot connection always goes to the correct part of the device’s internal wiring, such as the switch, and not to the casing or chassis, reducing the risk of electric shock.

2. Certain devices (like lamps or older appliances) can be more safely unplugged or serviced if the switch always cuts off the hot wire.

3. The longer neutral prong engages first and disconnects last when plugging in or removing the plug, helping prevent shock from exposed prongs.

If the hot and neutral could be flipped (with two same-sized prongs), the device might still work but could become dangerous, especially in older or ungrounded outlets.

In summary, the long prong is neutral to maintain proper electrical polarity and ensure consistent, safer operation of appliances and devices.