Currents as low as 20 mA can be dangerous if sustained; what does this imply about safety?

• A. Short, high-current bursts are always safer.
• B. Only voltages matter for safety.
• C. Duration of exposure matters, even at low currents.
• D. The conductor's color determines danger.

Answer: (C)

The main point is that safety depends on both how much current can pass and how long it can pass through the body. Even a small current, like 20 mA, can cause harm if it is sustained, because the energy delivered to tissues accumulates over time. This can lead to painful shocks, muscle contractions that can impair breathing, and even heart rhythm problems. So the risk isn’t eliminated just because the current is relatively small—it rises with both the strength of the current and the duration of exposure. In practice, this means always de-energize and limit exposure time, rather than assuming a low current is safe. Short, high-current bursts aren’t inherently safe either, since the instantaneous energy can still cause serious effects; focusing on duration and proper protection is essential. The danger isn’t related to the color of the conductor, and voltage alone doesn’t tell the whole story.