Electrical continuity

The key to safe operation is to provide an adequate means of charge dissipation from charged materi s to ground. This requires mobility of charges in or on the charged materialp/ii.s electrical continuity from the material to ground. 

Skeats, W.F. and Sverdlow, N., Minimising the magnetic filed surrounding isolated phase bus by electrically continuous enclosures , AIEE Trans. No. 62 (1962). 

The cathodic protection of reinforcing steel and stray current protection measures assume an extended electrical continuity through the reinforcing steel. This is mostly the case with rod-reinforced concrete structures however it should be verified by resistance measurements of the reinforcing network. To accomplish this, measuring cables should be connected to the reinforcing steel after removal of the concrete at different points widely separated from each other. To avoid contact resistances, the steel must be completely cleaned of rust at the contact points. 

Measured values of >1 Q show that the continuity is insufficient. The reinforcing steel should then be short circuited with the rest of the reinforcement, which has a sufficient electrical continuity. 

The 23 line drawings in [130] are very helpful for most routine bonding and grounding applications and for many years have been reproduced in NPCA 803 [6j. The following two sections cover general nonroutine applications. Chapters 5 and 6 of this book address specific grounding applications and special cases where electrical continuity may be unexpectedly lost. 

Cargo hoses with internal bonding between end flanges to be checked for electrical continuity before introduction into service and periodically thereafter. 

Although iron pipes suffer from the same corrosion risk as steel pipelines, associated with the generation of a galvanic cell with a small anode and a large cathode, the risk is mitigated for iron pipelines because the electrical continuity is broken at every pipe joint. For this reason long-line currents are uncommon in iron lines and cathodic protection is rarely necessary. It also accounts for the ability to protect iron lines by the application of nonadherent polyethylene sleeving . 

Scrap steel In some fortunate instances a disused pipeline or other metal structure in close proximity to the project requiring cathodic protection may be used. However, it is essential in cases of scrap steel or iron groundbeds to ensure that the steelwork is completely electrically continuous, and multiple cable connections to various parts of the groundbed must be used to ensure a sufficient life. Preferential corrosion can take place in the vicinity of cable connections resulting in early electrical disconnection, hence the necessity for multiple connections. 

In the UK the most common method of reducing interaction is to connect the protected and unprotected structures together by means of metallic bonds. This method is more successful if care has been taken to ensure that the unprotected structure is electrically continuous. If possible, bonds should be connected to points on the unprotected structure where maximum positive changes in potential are observed, but it may be more practicable to install a shorter bond between points where access can conveniently be obtained for periodic inspection and tests. 

If the electrical continuity of a buried pipe or cable is broken at a point where a.c. is liable to flow owing to the presence of a bond, the gap should be bridged by means of a continuity bond. This will prevent the appearance of a dangerous voltage between the two sections of pipe or cable. 

Continuity Bond electrical connection made to connect together adjacent sections of a buried structure in order to ensure its electrical continuity. 

Electrical continuity techniques have been used to determine the extent of deposition with standing time (Ref 9). New techniques have also been developed to stabilize PC used for coating propint grains in rocket motors. These... 

Bonding A method of providing electrical continuity between two or more conductive objects to prevent electrical sparking between them. 

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