Socket outlets

Plugs, socket-outlets and couplers for industrial purposes. Dimensional interchangeability requirements for pm and contact-tube accessories. Superseded BS EN 60309-2 1998, which remains cuiTcnt... 

Each item of apparatus tested, all flexible cords, switches, fuses, plugs and socket outlets are in good serviceable condition except as stated. There is no sign of overloading of conductors or accessories except as stated. Apparatus tested includesjdoes not include Portable Appliances. 

Switches, contactors, socket-outlets, connectors, air resonators, washing machine pulleys... 

Where the distribution circuit feeds a stationary item of equipment, not socket outlets and not portable equipment, the disconnection time may be taken as 5.0 seconds. This apphes to motors. 

The nominal time of 0.4 seconds is intended for circuits supplying socket outlets, regularly moved portable equipment and Class 1 hand-held equipment. For voltages (Vp ) different from 240 Vac, the disconnection time (fdis) of 0.4 seconds becomes approximately related as. 

Static loads encompass heaters, battery chargers, uninterruptible power supplies, lighting distribution boards, socket outlets, cathodic protection, navigational aids, computers, public address, radio communication and the like. Excluded are loads that are not predominantly composed of motors. The load may have fractional kW motors for cooling fans. 

It has become standard practice in recent years to use sensitive earth leakage current detectors in circuit breakers to further protect against electric shock. The current sensitivity can be chosen from a range of standard current values, e.g. 30, 100, 500 and 1000 mA. The 30 mA sensitivity is used at individual consumer sub-circuits, e.g. feeders to domestic and small power socket outlets, feeders to luminairs. The higher sensitivities are used in the upstream circuit breakers so that protection discrimination is achieved. 

Plugs and socket-outlets for domestic and similar general use. Recommendations for the classifications of insulating materials in relation to their thermal stability in service. 

Plugs, socket-outlets and couplers for industrial purposes. 

Part 3 Particular requirements for plugs, socket-outlets, connectors and appliance inlets for use in explosive gas atmospheres. 

The use of a 51 N should be considered when time coordination is required with distribution board consumers e.g. lighting, small power socket outlets and welding socket outlets. Static loads which do not feed downstream consumers should be fitted with a 50 N relay. 

Thermosets are hard. They are cross-linked with a narrow mesh in all directions. They are impervious to plastic deformation, infusible, and highly temperature resistant. Because thermosets are densely cross-linked, they are impossible to dissolve and quite difficult to swell. They are hard and brittle at room temperature. Electrical socket-outlets are manufactured from thermosets, for example, because resistance to high and low temperatures is very important here. Thermoplastics are incapable of meeting these requirements. 

Direct plug-in equipment. Products intended to be used without a power supply cord the mains plug is an integral part of the product s enclosure, and the weight of the product is supported by a socket-outlet. 

CAUTION. Plug on power cord is disconnect device. The wall s socket-outlet shall be installed near the product and easily accessible, (for pluggable equipment without disconnect device)... 

Portable tools must be fed from a 110 V socket outlet unit (see Fig. 1.29(a)) incorporating splash-proof sockets and plugs with a keyway which prevents a tool from one voltage from being connected to the socket outlet of a different voltage. 

Socket outlet and plugs are also colour coded for voltage identification ... 

Thermosetting polymers Once heated and formed, products made from thermosetting polymers are fixed rigidly, Plug tops, socket outlets and switch plates are made from this material. 

An isolator is a mechanical device which is operated manually and used to open or close a circuit off load. An isolator switch must be provided close to the supply point so that all equipment can be made safe for maintenance. Isolators for motor circuits must isolate the motor and the control equipment, and isolators for discharge lighting luminaires must be an integral part of the luminaire so that it is isolated when the cover is removed or be provided with effective local isolation (lET Regulation 537.2.1.6). Devices which are suitable for isolation are isolation switches, fuse links, circuit-breakers, plugs and socket outlets. They must isolate all live supply conductors and provision must be made to secure the isolation (lET Regulation 537.2.2.4). 

Plugs and socket outlets cannot be considered appropriate for emergency disconnection of supplies. 

A 20 A radial socket outlet circuit is wired in 2.5 mm PVC cable incorporating a 1.5mm CPC. The cable length is 30m installed in an ambient temperature of 20°C and the consumer s protection is by 20 A MCB Type B to BS EN 60898. The earth fault loop impedance of the supply is 0.5 fi. Calculate the total earth fault loop impedance Zs, and establish that the value is less than the maximum value permissible for this type of circuit. 

The maximum permitted value given in Table 41.3 of the lET Regulations for a 20 A MCB protecting a socket outlet is 2.19 as shown in Table 3.2. The circuit... 

A 230V ring main circuit of socket outlets is wired in 2.5 mm single PVC copper cables in a plastic conduit with a separate 1.5 mm CPC. An earth fault loop impedance test identifies Zg as 1.15Verify that the 1.5 mm CPC meets the requirements of lET Regulation 543.1.3 when the protective device is a 30A semi-enclosed fuse. 

Unrestricted local heating may be provided by portable electric radiators which plug into the socket outlets of the installation. Fixed heaters that are wall mounted or inset must be connected through a fused connection and incorporate a local switch, either on the heater itself or as a part of the fuse connecting unit. Heating appliances where the heating element can be touched must have a DP switch which disconnects all conductors. This requirement includes radiators which have an element inside a silica-glass sheath. 

Figure 3.68 Recommended method of connecting IT equipment to socket outlets.

PVC cables enclosed in heavy-duty PVC conduit are suitable for installations in most agricultural buildings. All exposed and extraneous metalwork must be provided with supplementary protective bonding in areas where livestock is kept (lET Regulation 705.415.2.1). In many situations, waterproof socket outlets to BS 196 must be installed. All socket outlet circuits must be protected by an RCD complying with the appropriate British Standard and the operating current must not exceed 30 mA. 

Touring caravans must be supplied from a 16A industrial-type socket outlet adjacent to the caravan park pitch, similar to that shown in Fig. 3.75. Each socket outlet must be provided with individual over-current protection and an individual residual current circuit-breaker with a rated tripping current of 30 mA (lET Regulations 708.553.1.12 and 708.553.1.13). The distance between the caravan connector and the site socket outlet must not be more than 20 m (lET Regulation 708.530.3). These requirements are shown in Fig. 3.77. 

The caravan should be connected to the pitch socket outlet by means of a flexible cable, no longer than 25 m and having a minimum cross-sectional area of 2.5 mm or as detailed in Section 721 of the lET Regulations. 

Outside zones - appliances are allowed plus accessories except socket outlets unless the location containing the bath or shower is very big and the socket outlet can be installed at least 3 m horizontally beyond the zone 1 boundary (lET Regulation 701.512.3) and has additional ROD protection (lET Regulation 701.411.3.3). 

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