Shock, arc, stored energy and protective limitations
Distinguish the main injury mechanisms
Electric current through a person can cause injury without immediately visible skin damage. French terminology distinguishes electrisation from electrocution, with the latter describing a fatal electrical accident. Consequences depend on factors such as pathway, current, duration, contact conditions and the person. A single threshold must not be treated as a universal safe current. Moisture can reduce contact resistance and alter risk; secondary injury can also occur through an involuntary movement or fall.
Understand an arc hazard
A short-circuit arc can produce intense thermal radiation, molten material and pressure effects. Nominal voltage alone does not describe the available energy, and prospective fault current is different from ordinary load current. Relevant protective arrangements depend on the actual installation and assessed task. An insulating glove, a face shield or an apparently low voltage does not automatically provide complete protection against every electrical hazard. Appropriate ratings, condition and compatibility all matter.
Identify what remains after stopping
A motor stopping or a display going dark does not establish absence of hazardous voltage. Capacitors, batteries, alternative supplies and induced effects can create relevant hazards under the actual system. An emergency stop function is not automatically an isolating device. A contactor’s open state is not proof of secure isolation. The proper safe system must identify the real sources and stored energy rather than rely on the appearance of one control.
Explain protection without overpromising
Insulation, barriers, protective earthing, bonding and automatic disconnection serve related but distinct purposes. A residual-current device detects the relevant imbalance, but does not cover every contact or provide overcurrent protection unless that function is included. An insulating mat can reduce a particular pathway without making phase-to-phase contact safe. Collective measures have priority within the actual preventive approach, complemented by suitable individual protection. Written recognition of a marking does not establish that equipment is undamaged, appropriate or correctly used. This supporting chapter contains physical principles, not universal French disconnection times, distances, conductor sizes or permission to approach bare live parts.