Reference number. IEC (E). INTERNATIONAL. STANDARD. IEC 22 02 11 Telefax: +41 22 03 00 E-mail: [email protected] Web: aracer.mobi IEC Edition INTERNATIONAL. STANDARD. NORME. INTERNATIONALE. Protection against electric shock – Common aspects for. The European Standard EN has the status of a The text of the International Standard IEC , prepared by IEC TC
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and equipment. Reference number. IEC (E). INTERNATIONAL. STANDARD. IEC The technical content of IEC publications is kept under constant review by the IEC, thus ensuring that version online. IEC Ed. - PDF. An international Standard such as the IEC series “Low voltage .. of IEC series, IEC , series and IEC are the fundamentals. ▫IEC Protection against electric shock - Common aspects for installation and equipment (under revision). IEC ; Formats available: PDF Connectors .
A single fault could cause an electric shock or other dangerous occurrence, without triggering the automatic operation of any fuse or circuit breaker. A typical example of a Class 0 appliance is the old style of Christmas fairy lights.
However, equipment of this class is common in some V countries, and in much of the V developing world, whether permitted officially or not. These appliances do not have their chassis connected to electrical earth.
In many countries the plug of a class 0 equipment is such that it cannot be inserted to grounded outlet like Schuko. The failure of such an equipment in a location where there are grounded equipment can cause fatal shock if one touches both. Any equipment with a schuko plug will act like a Class 0 equipment when connected to an ungrounded outlet.
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.
A fault in the appliance which causes a live conductor to contact the casing will cause a current to flow in the earth conductor. If large enough, this current will trip an over-current device fuse or circuit breaker CB and disconnect the supply.
The disconnection time has to be fast enough not to allow fibrillation to start if a person is in contact with the casing at the time. These appliances must have their chassis connected to electrical earth US: 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.
A fault in the appliance which causes a live conductor to contact the casing will cause a current to flow in the earth conductor.
If large enough, this current will trip an over-current device fuse or circuit breaker CB and disconnect the supply. The disconnection time has to be fast enough not to allow fibrillation to start if a person is in contact with the casing at the time.
This time and the current rating in turn sets a maximum earth resistance permissible. To provide supplementary protection against high-impedance faults it is common to recommend a residual-current device RCD also known as a residual current circuit breaker RCCB , ground fault circuit interrupter GFCI , or residual current operated circuit-breaker with integral over-current protection RCBO , which will cut off the supply of electricity to the appliance if the currents in the two poles of the supply are not equal and opposite.
Electrical installations where the chassis is connected to earth with a separate terminal, instead of via the mains cable.
In effect this provides the same automatic disconnection as Class I, for equipment that otherwise would be Class 0.
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.
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. For medical devices, compliance with Class III is not considered sufficient protection, and further more-stringent regulations apply to such equipment.
From Wikipedia, the free encyclopedia.