A Class II or double insulated electrical appliance uses reinforced protective insulation in addition to basic insulation. Hence, it has been designed in such a way that it does not require a safety connection to electrical earth (ground).
Firstly Double Insulated and Class 2 mean exactly the same thing, this being that these lights are designed to be used where the property they are being fitted into has no earth wire.
Double insulated lighting (Class II Lighting) is safe to use where an earth is not present. This is particularly useful when adding lights to an older house which might not have an earth cable where the light is intended to go.
On the other hand, Class II devices are double-insulated appliances. These are manufactured with non-conductive enclosures, such as plastic, and are usually marked with a double-boxed symbol. Class II devices do not require an earthing conductor and should not be earthed.
Class 2 relates to the power supply's safety, and it limits the maximum power that the power supply can deliver. Class 2 power supply is popular in the automation, control, and the power supply lighting industry because of lower safety protection requirements, decreasing complexity and cost during installation.
In Class 2 appliances, the user is protected by at least two layers of insulation. For this reason, Class 2 appliances are also known as Double Insulated. They do not require an earth connection. When PAT Testing Class 2 appliances, just the Insulation Resistance test is carried out.
Class II is where the lower first molar is posterior (or more towards the back of the mouth) than the upper first molar. In this abnormal relationship, the upper front teeth and jaw project further forward than the lower teeth and jaw.
Double Insulated/Double Insulation
In the United Kingdom, a double insulated appliance must be labelled Class II, double insulated, or bear the double insulation symbol (a square inside another square). An example of a double insulated electrical appliance could be an electric drill or a desk fan.
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).
So essentially Class I equipment has an earth which will be visibly terminated in the plug top & has an earth incorporated in the supply cable. Class II equipment does not rely on an earth connection for safety therefor inside the plug you will only see 2 wires (L+N) & is supplied by a 2 core cable.
Class 2 double insulated lights are designed to operate without the need for an earth wire. They usually have two layers of insulation which cover the live parts, for example the cables inside the fitting.
Such equipment is identified by being distinctively marked. This marking consists of the double insulation symbol (a square within a square) and the words "double insulation" of the equivalent words "double-insulated."
Double insulated lights (sometimes known as Class 2 lights) are lights that don't require an earth wire. They are most commonly found in older properties, those built before or during the 1960s, which are not earthed.
Class II. A Class II appliance usually has a plastic cover. The only way to accurately identify it is to look for the Class II appliance symbol. Examples of Class II appliances are hair dryers, DVD players, televisions, computers, and photocopiers. Class II appliances have two layers of insulation.
A Class 2 power-limited cable for use in thermostat controls applications, bell and alarm systems, not to exceed 150 volts when installed as specified by the National Electrical Code® (NEC) and other applicable standards.
These appliances are also referred to as having “double insulation” since in class II appliances a supplementary insulation is added to the basic insulation (see Figure F70).
Protection class II - protective insulation means protection through double or reinforced insulation, i.e., safe electrical separation. Special features of SK II. Luminaires with protection class II have no connection to the protective conductor.
Double Insulated Lighting Products
From the outside a double insulated light looks exactly the same as a normally earthed light. You cannot tell the difference in any way from just looking at a product. Once you delve inside the products however it becomes quite clear what the differences are.
Some examples of class 1 appliances are toasters, kettles, washing machines and irons.
Typical examples are blenders, coffee makers, blow dryers, drills, and other power tools. Appliances and tools of this type are called "double insulated". They have two levels of insulating materials between the electrical parts of the appliance and any parts on the outside that you touch.
Meter tails are regarded as being double insulated; and. Steel Wire Armoured (SWA) cables are regarded as having reinforced insulation.
To be considered Class 2 compliant, power supplies must have a maximum power capacity of 100VA and cannot exceed a 30V AC or 60V DC output. The specific maximum wattage and current rating for a power supply will depend on the output voltage.
Classification is the word we use to describe the process of observing a living thing and deciding which group it belongs to, based on its key characteristics. For example, a lion has fur, gives birth to live young, is warm-blooded, has a backbone and lives on land.
Code 2: vehicles (except motorcycles) with tare weight of 3,500 kilograms or less; minibuses, buses and goods vehicles with GVM of 3,500 kg or less; and articulated vehicles with GCM of 3,500 kg or less.