Guidelines on the types and correct uses of IEC connectors.
We have received a number of examples of the incorrect use of IEC BS EN 60320 connectors. There are a total of eleven IEC connectors in common use (see Figure 1), some two-pin and some three-pin, having a current rating ranging from 0.2A for the C1 and C2 connector up to the 16A C21 and C22 connector.
Figure 1 Types of IEC connectors in common use
The range of two-pin connectors are intended for use on Class II equipment, double insulated devices that do not need to be earthed. The range of three-pin connectors are intended for use on Class I equipment, devices that require an earth connection.
Examples have been found in which mains leads having three-pin IEC connectors and two-core cable have been supplied for use with Class II medical devices. Although this is not a hazard when the lead is used with the device for which it was supplied, it is possible for users to interchange mains leads between devices; as a consequence the two core lead can be used with a device that requires an earth connection. This could lead to a person who touches the device receiving a shock due to normal earth leakage current. Devices supplied with a two-pin IEC connector can safely be provided with a standard 13A plug, which may in some cases have an insulated earth pin that is needed only to open the shutters on the socket (see Figure 2). However, a lead having two cores may only be fitted with a two-pin IEC connector.
Figure 2 Two-pin IEC connector with insulated earth pin
Any mains leads fitted with a three-pin IEC connector must have a three-core cable together with a standard three-pin 13A plug.
Actions
- Remove any two core mains leads fitted with three-pin IEC connectors from service.
- Do not interchange mains leads between devices. Order replacement mains leads from the device manufacturer.
- Inspect all removable mains leads and check that any lead fitted with a three-pin IEC connector has a connection between the earth pin of the connector to the earth pin of the mains plug. If any mains leads are found to have a three-pin IEC connector, but do not have an earth connection to the earth pin of the 13A plug, report the issue to the equipment manufacturer, and request a replacement lead.
