Which of the following is a safety hazard related to stray voltage?

Stray voltage is primarily a safety concern because it refers to voltage that is unintentionally present on conductive surfaces, which can happen due to poor grounding, capacitance from nearby electrical installations, or other factors where the voltage does not have a deliberate path to ground. When voltage is present on surfaces that people may touch or where animals might come into contact, it poses a significant risk of electric shock. This hazard is particularly dangerous because the voltage may not be enough to trigger a circuit breaker or be detected by standard electrical testing, making it insidious and difficult to identify.

In the context of the other choices, while inconsistent lighting levels, overheating of electrical wires, and inadequate grounding of circuits can be problematic in an electrical system, they do not specifically address the issue of stray voltage or highlight the immediate risk it poses to safety. The presence of voltage on conductive surfaces is what fundamentally characterizes the hazard associated with stray voltage.