How many volts will kill a rat? - briefly
A voltage in the range of roughly 100 – 200 V AC can be fatal to a rat, though the decisive factor is the current (about 10 mA) and exposure duration. Lower voltages may also kill if sufficient current flows for a prolonged period.
How many volts will kill a rat? - in detail
Rats are small mammals with body resistance that typically ranges from 1 kΩ to 10 kΩ, depending on skin moisture, electrode placement, and body mass. The current required to cause cardiac fibrillation or respiratory arrest in mammals is about 100 mA (0.1 A). Applying Ohm’s law (V = I × R) yields a voltage interval of roughly 100 V to 1 000 V for a rat, assuming the lower resistance of a wet pathway and the higher resistance of dry skin.
Key variables influencing the lethal voltage:
- Current type: Alternating current (AC) is more hazardous than direct current (DC) at the same voltage because it interferes with the heart’s rhythm.
- Exposure duration: Short pulses (milliseconds) may be non‑lethal even at high voltage, whereas sustained contact for seconds increases fatal risk.
- Electrode placement: Paths crossing the heart or central nervous system require less voltage to be fatal than peripheral routes.
- Skin condition: Moist or damaged skin lowers resistance, reducing the voltage needed for a lethal current.
Experimental data on rodents indicate that a 60 Hz AC exposure of 120 V applied across the thorax for 5 seconds produces a 0.12 A current, which reliably results in death. Higher voltages (e.g., 240 V) cause immediate cessation of cardiac activity with exposure times under one second.
In practice, any voltage capable of delivering 0.1 A through a rat’s body—typically above 100 V under wet conditions—poses a fatal threat. Safety protocols for laboratory work therefore treat voltages exceeding 50 V as potentially lethal for small mammals, mandating insulation and protective barriers.