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All electrical appliances working with mains voltage have to present at minimum two degrees of safety to the consumer. This is to ensure that if 1 of the safety levels had been to fall short, there is the back-up of the 2nd layer still in put. This will make electrical products very safe to use. Appliances can be Class 1 or Course 2.When PAT tests, it is critical to initially discover the Course of the appliance as Course 1 appliances are tested in a different way from Course two appliances.Based on how precisely the defense is supplied, electrical appliance are place into 5 Courses of equipment building which are Course 1, two, 3, , 01. Of these the most essential are Course one & two. For completeness all the Lessons are described underneath.Course oneIn this article the defense is presented by a combination of insulation and use of the mains Earth. It is ideal revealed by referring to an electrical fire that has been taken apart.In the open plug the a few wires connecting to the Are living, NEUTRAL and EARTH pins. Inside of the fireplace, the brown Dwell wire and the blue NEUTRAL wire join to a plastic connector. The eco-friendly/yellow Earth wire connects to the steel circumstance of the fire.The user is safeguarded from electric powered shock by the plastic insulation of the connector. This retains the Dwell and NEUTRAL wires in area and prevents them from touching the metallic scenario of this electric fireplace. This plastic insulation of the connector is recognised as standard insulation.If this standard insulation ended up to fall short, say owing to too much motion of the cable wherever it touches the metallic situation then the consumer of the hearth can receive an electric powered shock if not for the truth that the EARTH wire is current.By connecting to the metal situation of the electric fire, the EARTH wire retains all this metallic at EARTH likely. What this indicates is that it is unattainable to get an electric powered shock even when the metal scenario of the fire is linked instantly to the Stay voltage. In exercise a fuse would blow both in the plug or the most important fuse box to safeguard the user.In summary, in Class 1 appliances the consumer is protected by a mixture of standard insulation and the provision of an EARTH relationship, hence giving two stages of safety.When PAT Tests Course one appliances, the Earth Continuity and Insulation Resistance exams are carried out.Class 2In a Course 2 appliance, the user is secured by at minimum two levels of insulation. For this reason, Course 2 appliances are also recognized as Double Insulated. They do not involve an Earth relationship.This is most effective demonstrated by seeking inside of a Course two electric drill which has been opened up. Within a person can see that as very well as the plastic connector supplying simple insulation, there is extra insulation delivered by the plastic enclosure of the drill.The consumer is thus guarded by two different levels of insulation. When PAT tests Class 2 appliances, just the Insulation Resistance exam is carried out.Class 2 appliances are usually indicated by the double box symbol on the ranking plate.Course 3Tools created to Course 3 normal are created to be provided from a unique protection isolating transformer whose output is known as Safety Further-Minimal Voltage or SELV. This need to not exceed 50 V AC and is generally is beneath 24V or 12V. All Class three appliances are marked by a exclusive symbol. There is no use of an Earth in Course III applianceThe electrical protection of Class three appliances are taken treatment of in the protection isolating transformer style and design the place the separation amongst the windings is equivalent to double insulation. The transformer is marked as currently being ideal for use with Course III appliances.Class & 01This variety of products is not for standard use in business or residential environments. It is just offered in this article for completeness.Class appliances count only on simple insulation for safety from electrical shock. For this purpose, they do not have 2 levels of safety created in and are not allowed for sale. The brass lamp proven listed here is an illustration of a two wire, steel cased equipment with only fundamental insulation. There is no provision for link of an earth to the bulb holder.In Class 01 appliances, there is provision for an Earth relationship, but it is wired with both twin main cable or only has a two-pin plug, so an Earth can't be connected. AS in Class machines, a single is dependent only on simple insulation for security from electric shock. As they only have 1 degree of safety, Course 01 appliances are not authorized for sale.If through PAT testing a single arrives throughout a Class or Class 01 equipment these can be failed.Figuring out Class I & Course II EquipmentAs the PAT screening carried on Course one and Course two appliances vary, it is critical to determine a single from the other. There is no other region of PAT testing that triggers a lot more confusion than this and there are quite a few myths encompassing this. It will be useful to listing some of these.If there is a fuse in the plug, then it will have to be Course one.It is made of metal so it have to be Course oneThe circumstance is plastic so it must be Course 2It has a three main cable so it must be Course 1The plug has a metal Earth pin so it should be Course 1None of the higher than statements is a idiot-evidence way to establish Course I and Course II appliances and some are very deceptive.The easiest rule to use is the just one below.If the rating plate has a double box then the equipment is Class 2. If it does not then it is Class 1.Case in point - KettleThe rating plate on this kettle evidently has no "double-box" image, so employing our rule, it should be Class 1. The Earth connection from the plug is terminated on the outside steel casing of the heating component. When PAT tests this kettle the Earth Continuity and Insulation Resistance take a look at has to be carried out.Example - Plug-prime electrical power sourceThe ranking plate on this Plug-top rated transformer evidently shows the "double box" symbol, so this is a Course two appliance. Be aware that it has a plastic Earth pin, as this is not needed for Course II. (Not all Class two appliances have a plastic earth pin). Just the Insulation Resistance examination has to be carried out for the duration of PAT screening.Case in point - Mains extensionThe rating plate on this extension is moulded in the plastic. It clearly does not have a "double-box" image, so it should be a Class one. When PAT testing this extension lead the Earth Continuity and Insulation Resistance check has to be carried out.Illustration - Desk lampThe ranking plate on this desk lamp obviously reveals the "double-box" so it is a Course 2 appliance. (Notice that this is a Course 2 appliance that is mostly in a metallic enclosure). The bulb holder is made of plastic and supplies the necessary double insulation. Just the Insulation Resistance test has to be carried out throughout PAT screening.