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More Information on Rewireable Plugs,
Sockets, and Cable Connectors

International Sockets

Use international sockets and socket strips to test or burn-in electrical and electronic equipment that will be exported with international power cords and cord sets. This allows testing of the equipment, complete with the power cord, in exactly the same manner that your global customer will use it.

Sockets for both international and North American applications are covered in this section. We also have a full line of socket strips. Our International Socket Strip and the International Power Source can be used in test or burn-in setups. They can be found in the Testing and Safety product line.

International sockets can also be used as convenience power outlets or in conjunction with power distribution devices in large electronic systems. For example, computer systems occupying one or more racks may include an appropriate international convenience power outlet for use by a service technician. Large communications or military electronics systems can utilize power controllers or distribution devices equipped with international sockets that are appropriate for the country in which they will be used.

International Plugs

Rewireable international plugs are used primarily when it is advantageous to build a special-purpose power cord, cord set, or extension cord that is not available in the quantity required as a molded “standard” product. This could be, for example, a power cord or cord set with a higher rating than normally stocked in a molded version or a non-standard cable jacket color or conductor size. These requirements are often best satisfied with a special power cord or cord set that is assembled from standard cable and rewireable plugs and connectors. A cable assembled with rewireable components can be produced in quantities as small as one piece.

For a guide to where the plugs and sockets in this section are used, see our Guide to Worldwide Plug and Socket Patterns & Power Mains.

North American Plugs and Sockets

The North American plugs, connectors, and receptacles in this catalog are described in standards published by NEMA (National Electrical Manufacturer’s Association) in the United States and by CSA (Canadian Standards Association) in Canada. The standards identify unique pin and receptacle configurations based on amperage and voltage ratings. Both straight blade and locking configurations are included in the standards. The NEMA 5-15 straight blade configuration is used most often in the U.S. and Canada.

If you require a power connection above 16A/125VAC that can also be used internationally, consider designing your product with Interpower high power pin and sleeve devices.

If your product will be used in a dusty environment, consider specifying our dust-resistant inlets. An extra gasket seals the inlet's flange against the equipment panel.

If there is only a small space behind your panel to mount a plug or socket, take a close look at our line of flanged inlets and outlets. A flanged nylon housing allows mounting in a panel from the front of the panel, without access from the rear.

Our North American plugs, connectors, and receptacles have been designed and tested for grounding reliability, assembly integrity, strength, and durability. They meet or exceed the requirements of UL Standard 498 (Attachment plugs and Receptacles) for abrupt plug removal; ground pin retention; fault current; terminal strength; ground contact temperature and resistance; assembly security; cord grip strain relief and cord pull; and various durability and impact tests of the material.

Australian Medical Requirements

Medical equipment used in Australia must meet AS/NZS 3200. There are no special requirements for plugs, only preferences. All Australian plugs must be approved to AS/NZS 3112. In Australian medical applications, it is preferred by hospitals to have a clear, transparent plug and orange, flexible cable.These plugs and connectors must carry one of the many Australian approvals.

North American Hospital-Grade Requirements

Hospital-grade plugs are subject to special requirements contained in the following attachment plug standards: UL 498 and CAN/CSA C22.2 no 42. Our hospital-grade plugs, connectors, and receptacles carry the “green dot” signifying that they have been designed and tested for grounding reliability, assembly integrity, strength, and durability. Specifically, they meet or exceed the requirements of UL Standard 498 (Attachment plugs and Receptacles) and UL 60601 (Medical and Dental Equipment) for abrupt plug removal; ground pin retention; fault current; terminal strength; ground contact temperature and resistance; assembly security; cord grip strain relief and cord pull; and various durability and impact tests of the material. Locking terminals ensure reliable power connections, which is very important on patient-connected medical equipment.

For more information on North American hospital-grade requirements, see the hospital-grade cords information section.

Danish Hospital-Grade Requirements

The Danish hospital-grade plug and socket are recommended for use in medical applications and specifications are being added to the standard SB 107-2-D1, which was published at the end of 2003. The socket is designed to prevent “normal equipment” from being connected and disrupting the mains circuit in specific medical settings. We do not have molded connections at this time.

International Medical Markets

International markets, including European medical equipment used in these markets, typically must meet EN/IEC 60601-1. At this time, there are no special performance or construction requirements for plugs and sockets used in these applications.

Custom Cord Preparation Services

Interpower Corporation’s in-house UL/CSA assembly services can prepare special power cords, cord sets and extension cords using components described in this section. For more information on our “Made-to-Order” cord Assembly capabilities and additional specifying assistance, please contact our Customer Service Department toll-free at (800) 662-2290 or e-mail us at

British Plug and Ring Wiring System

The United Kingdom is the only country that requires a fused power plug. The British use a ring wiring system in their houses and buildings, which provides a secondary protection device at the plug, to minimize safety hazards. Circuits leave the local branch protection device, travel out to the loads (outlets or lamps, for example), and then return to the circuit protection device. In the Continental European and North American systems, all wiring is done on a linear basis—a circuit leaves the circuit protection device and goes straight to the outlets or lighting circuits, that represent the load, as illustrated below.

In the British ring wiring system, a fault condition at an outlet, for example, will be sourced with current from both directions. This minimizes the amount of heat generated in the conductor, as the fault condition occurs, but before the circuit protection device can clear the fault. By minimizing the heat generated, the degradation of insulation (which accompanies overheating due to repeated fault conditions) is also diminished, improving the long-term safety of the insulation system.

Until the circuit protection device clears the fault, however, the fault condition is sourced from two different directions in the supply system. There is therefore a much greater potential fault current condition. The British feel that a secondary protection device at the plug minimizes the safety hazard this condition creates; hence, the power plug fuse.

The fuse installed in all British plugs conforms to BS 1362 ("General purpose fuse links for domestic and similar purposes…"). The size of this fuse is 6.3 x 25.4mm. It has a breaking capacity rating of 6000A and is constructed with a sand-filled ceramic tube. The time-current characteristic on this family of fuses is not necessarily consistent with any other international standard, but it appears to have most of the characteristics of a fast acting fuse. The British Standards Institution standard for fuses in general is BS 4265.

North America 15 and 20A Plugs and Connectors

Superior design makes assembly connections easy and secure!

  • Wire entry holes are close together, requiring less conductor strip.
  • Stripped wires slip easily into funnel-shaped guides for quick assembly; deep funnel design eliminates the need for lead tinning.
  • Combination slotted/Phillips head terminal screws are handy both for assemblers
    and end-users in the field. Terminal screws are open for quick assembly and terminals are
    clearly marked when necessary.
  • Unique locking assembly (see illustration at left) ensures that the terminal screw will remain locked in place even with heat-cycling and vibration. Terminal screw compresses wires securely underneath a contact tang, ensuring solid connections.
  • Seal keeps dust out of wiring chamber
  • Internal cord clamp cannot be broken or accidentally loosened.
  • Cord clamp accommodates a large range of cable diameters.
  • Housings are made of nylon material and are very shock-absorbent.

Data Circuits - Danish and British

Computers and other electrical devices that contain sensitive digital circuits, usually need to be protected from spikes and surge currents conducted into the product via the line cord. In North America, this is normally accomplished with the use of plug-in surge protectors that are dedicated to one computer or work station.Although not yet as common in Europe as in the U.S., surge protection is frequently provided in Europe through the use of centrally protected circuits. In these installations, a power distribution system that can exclude non-protected appliances is desirable. The reason is that the presence of an inductive load, such as a vacuum cleaner for example, on a protected circuit would potentially reinsert brush noise and spikes as the vacuum was turned on and off. This could completely negate the central surge protection.The basis of the selective connection systems used in Denmark and the U.K., is the plug and socket. The Danish plug/socket is a Danish national standard. The British do not have an official standard on plugs and sockets for data circuits. But there is in fact, at least one unique data plug/socket system used by a large British computer manufacturer.

Danish data plug

The Danish plug/socket pair is designed with specially shaped line and neutral contacts. The protected socket (not shown) will accept only the Danish data circuit plug; however, this data circuit plug may also be inserted into a standard outlet, if a protected outlet is not available.

United Kingdom data plug and socket

The British plug/socket pair, designed for use with protected data circuits, incorporates a special "T" shaped ground contact, which allows the data circuit plug to connect only to a protected outlet. The outlet, similarly, excludes all other standard plugs.