Electric shock protection class

For electrical appliance the following IEC protection classes are defined in IEC 61140 and used to differentiate between the protective-earth connection requirements of devices.

Class 0
These appliances have no protective-earth connection and feature only a single level of insulation between live parts and exposed metalwork. If permitted at all, Class 0 items are intended for use in dry areas only. A single fault could cause an electric shock or other dangerous occurrence, without triggering the automatic operation of any fuse or circuit breaker.

Class 1
These Class I appliances must have their chassis connected to electrical earth (US: ground) by a separate earth conductor (coloured green/yellow in most countries). The earth connection is achieved with a 3-conductor mains cable, typically ending with 3-prong AC connector which plugs into a corresponding AC outlet.

Class 2
A Class II or double insulated electrical appliance is one which has been designed in such a way that it does not require a safety connection to electrical earth (ground).
The basic requirement is that no single failure can result in dangerous voltage becoming exposed so that it might cause an electric shock and that this is achieved without relying on an earthed metal casing. This is usually achieved at least in part by having at least two layers of insulating material between live parts and the user, or by using reinforced insulation.
In Europe, a double insulated appliance must be labelled Class II or double insulated or bear the double insulation symbol: ⧈ (a square inside another square).

Class 3
A Class III appliance is designed to be supplied from a separated extra-low voltage (SELV) power source. The voltage from a SELV supply is low enough that under normal conditions a person can safely come into contact with it without risk of electrical shock. The extra safety features built into Class I and Class II appliances are therefore not required. For medical devices, compliance with Class III is not considered sufficient protection, and furthermore, stringent regulations apply to such equipment.

Electric shock protection classes for luminaires, light bulbs, and LED lamps follow similar principles to those mentioned earlier. These classes indicate the level of protection against electric shock and are designated by specific symbols and classifications. As of my last knowledge update in September 2021, here are the relevant protection classes:

For Luminaires (Light Fixtures):

• Class I: Luminaires with basic insulation and an earth connection (grounding).
• Class II: Luminaires with double insulation (reinforced insulation) that do not rely on grounding.
• Class III: Luminaires that operate at extra-low voltage (e.g., 12V or 24V) and require a separate power supply providing SELV (Safety Extra-Low Voltage) or PELV (Protective Extra-Low Voltage).

For Light Bulbs and LED Lamps:

• Class I: Light bulbs and LED lamps with basic insulation and an earth connection.
• Class II: Light bulbs and LED lamps with double insulation.
• Class III: Light bulbs and LED lamps that operate at SELV or PELV.

Please note that the specific designations and symbols might vary slightly depending on the standard used in your region or country. Always refer to the latest standards and regulations, such as those provided by the IEC (International Electrotechnical Commission) or other relevant authorities, for accurate and up-to-date information.

Additionally, some products might have combined protection features, similar to luminaires, such as Class I/II or Class II/III, indicating a combination of insulation and grounding or low-voltage features.

Since standards and regulations can evolve over time, I recommend checking with the latest sources or consulting relevant experts or authorities in your region to ensure compliance with the most current electric shock protection classes for these products.