Earth bonding

Earthing connections, including any supplementary earthing bonding connections are satisfactory (for example connections are tight and conductors are of sufficient cross-section)... 

EARTH BONDING CHECKED ZENER BARRIERS CORRECT ... 

Earth bond size and location of earth bar to which the item is coimected... 

Visual inspection of signal shielding and earthing arrangements to eliminate noisy signals. Continuity checks on earth bonding. 

Plotted in Fig. 3.6 are the association constants of some 1 1 complexes of divalent metal ions versus their electronegativities. The figure shows that association constants for the bicarbonate and most of the sulfate complexes are practically independent of EN or AEN. For the alkaline earths, bonding with all four ligands is also largely ionic (i.e., independent of EN). These all must be, there-... 

Combined inspection and testing is also necessary on some equipment because some faults cannot be seen by just looking - for example, the continuity and effectiveness of earth paths on class I equipment. For some portable appliances the earth is essential to the safe use of the equipment and, therefore, all earthed equipment and most extension leads should be periodically tested and inspected for these faults. All portable appliance test instruments (PAT Testers) will carry out two important tests earth bonding and insulation resistance. 

Earth bonding tests apply a substantial test current, typically about 25 A, down the earth pin of the plug top to an earth probe, which should be connected to any exposed metalwork on the portable appliance being tested. The PAT Tester will then calculate the resistance of the earth bond and either give an actual reading or indicate pass or fail. A satisfactory result for this test would typically be a reading of less than 0.1 n. The earth bond test is, of course, not required for double-insulated portable appliances because there will be no earthed metalwork. 

Figure 3.82 Legrand adjustable earth bonding strap.

Flexible metallic conduit should have a non-metallic inner sheath or be suitably designed so that movement cannot cause abrasion of the cables. Flexible metallic conduit is not a suitable protective conductor. A flexible cable conductor should be used for this purpose to ensure earth continuity between the fixed conduit and apparatus, and the flexible conduit joints should be earth bonded at both ends. 

Fig. 10.33 Stray current corrosion, (a) A pipeline or cable may provide a lower resistance path than the soil, (b) Welding operations on a ship may give rise to stray currents if the earth bonding is insufficient, (c) Leakage currents may be induced by an overhead train cable.

Earth bonding checked Zener barriers correct ... 

Table 5 Relationship between rare earth bond energy and catalytic...

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