- Energy Source Classification
In relation to electrical safety, the term energy source classification is defined under the product safety standard AS/NZS 62368.1 (Audio/video, information and communication technology equipment - Safety requirements).
There are three defined electrical energy source classes: ES1, ES2, and ES3. Each classification determines the severity of the energy source, the potential risk of injury, and the level of safeguards required to protect ordinary users.
ES1 (Energy Source Class 1)
ES1 represents the lowest and safest tier of electrical energy exposure. Under both normal operating conditions and abnormal single-fault conditions, an ES1 circuit operates at low levels that are entirely safe to touch by an ordinary person and carries a negligible risk of causing an electrical fire or ignition.
ES2 (Energy Source Class 2)
ES2 represents an intermediate tier of electrical energy exposure. Under normal operating conditions, the voltage or current may be perceptible (a mild tingle) but is not painful or harmful. Under a single-fault condition, it may cause pain but is unlikely to cause injury. Because ES2 circuits carry a moderate risk of causing ignition, they require basic safeguards to protect ordinary users from both shock and electrical fire.
ES3 (Energy Source Class 3)
ES3 represents the highest and most hazardous tier of electrical energy exposure (such as standard household mains power). Both normal and fault conditions present a severe risk of painful electric shock, serious injury, or death. Because ES3 energy levels are high enough to easily ignite surrounding combustible materials, robust, double, or reinforced safeguards are strictly required to eliminate fire and injury hazards.