Conductors bonding

Current overload tests, including bonding conductors and connections tests... 

The method of calculating the cross-sectional area of busbars, interconnectors and bonding conductors is given in 9.4.3.5. 

The local processing equipment will be similar to that described in sub-section 13.2.1, and therefore the earthing practices will be similar, for example the use of copper interconnected busbars and bonding conductors. However, if the plant is mounted on concrete foundations then extra earthing rods will usually be needed at each foundation site. All reinforcing steelwork in concrete should be earthed to busbars or through their own rods. 

A permanent label must also be fixed in a visible position at or near the point of connection of the bonding conductor with the words Safety Electrical Connection - Do Not Remove (lET Regulation 514.13.1). Supplementary bonding is described later in this book. 

Bonding conductor - a protective conductor providing bonding. 

In rooms containing a fixed bath or shower, supplementary protective bonding conductors must be installed to reduce to a minimum the risk of an electric shock unless the following two conditions are met ... 

Supplementary protective bonding conductors in domestic premises will normally be of 4mm copper with PVC insulation to comply with lET Regulation 543.1.1 and must be connected between all exposed metalwork (e.g. between metal baths, bath and sink taps, shower fittings, metal waste pipes and radiators), as shown in Fig. 3.79. 

Crimp terminals are made of tinned sheet copper. The chosen crimp terminal is slipped over the end of the conductor and crimped with the special crimping tool. This type of connection is very effective for connecting equipotential bonding conductors to approved earth clamps. 

A satisfactory test result for the bonding conductors will be in the order of 0.05 or less (lET Guidance Note 3). 

The object of the test is to ensure that the CPC is correctly connected, is electrically sound and has a total resistance which is low enough to permit the overcurrent protective device to operate within the disconnection time requirements of Regulation 411.4.6, should an earth fault occur. Every protective conductor must be separately tested from the consumer s main protective earthing terminal to verify that it is electrically soimd and correctly connected, including the protective equipotential bonding conductors and supplementary bonding conductors. 

Reconnect the protective bonding conductors when the test is completed. 

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