Legal Definitions - novus actus interveniens

Novus actus interveniens is a Latin legal term that translates to "a new intervening act." It refers to an event or action that occurs *after* an initial wrongful act, but *before* the final harm or injury is suffered. This new, independent act is so significant and unforeseeable that it breaks the chain of causation between the original wrongful act and the ultimate outcome, potentially relieving the initial wrongdoer of liability for that ultimate outcome.

In simpler terms, if someone does something wrong, but then a completely separate and unexpected event happens that directly causes the final damage, the "novus actus interveniens" might mean the first person isn't responsible for all the damage because the second event was the true, independent cause of the ultimate harm.

• Example 1: Road Accident

  Imagine a driver, Mr. Smith, negligently runs a red light and lightly collides with Ms. Jones's car, causing minor damage and a slight whiplash injury to Ms. Jones. While Ms. Jones is waiting for the police to arrive and exchange insurance information, a completely unrelated and distracted truck driver, Mr. Davis, swerves off the road and crashes into Ms. Jones's car again, this time causing severe structural damage and critical injuries to Ms. Jones. Mr. Davis's reckless driving and subsequent crash would likely be considered a novus actus interveniens. While Mr. Smith is responsible for the initial minor damage and whiplash, the severe damage and critical injuries caused by Mr. Davis's independent and unforeseeable act would likely fall under Mr. Davis's responsibility, as his actions broke the chain of causation from Mr. Smith's initial negligence.

• Example 2: Construction Site Incident

  A construction company, "BuildCo," negligently leaves a deep trench uncovered and unmarked on a public sidewalk. A pedestrian, Ms. Chen, falls into the trench and suffers a broken ankle. While emergency services are in the process of carefully lifting Ms. Chen out of the trench, a rogue drone, operated by an unrelated hobbyist, malfunctions and crashes directly onto Ms. Chen, causing a severe head injury. The drone crash, being an independent and unforeseeable event that caused a distinct and more severe injury, could be considered a novus actus interveniens. BuildCo would be liable for Ms. Chen's broken ankle due to their negligence, but the severe head injury caused by the drone might be attributed to the drone operator, as the drone incident broke the direct causal link between the uncovered trench and the head injury.

• Example 3: Product Defect and Subsequent Misuse

  A manufacturer, "GadgetCorp," sells a new kitchen appliance with a minor electrical defect that causes it to occasionally spark. A customer, Mr. Lee, buys the appliance. One day, the appliance sparks, but instead of unplugging it and contacting the manufacturer, Mr. Lee attempts to fix the electrical issue himself using improper tools and without turning off the power. In doing so, he causes a major electrical fire that destroys his kitchen. While GadgetCorp's initial defect was a wrongful act, Mr. Lee's subsequent, independent, and grossly negligent attempt to repair the appliance himself could be considered a novus actus interveniens. This intervening act broke the chain of causation, meaning GadgetCorp might only be responsible for the minor sparking issue, while Mr. Lee's own actions would be the direct cause of the kitchen fire.