Definition - What does Continuity Bond mean?
A continuity bond is the metallic connection that yields constant electrical contact between two metal structures. It is the bond that connects components of metal with wires leading to electrical continuity. This is seen in most metal components under the waterline like propeller shafts, hulls and rudders.
Measuring the continuity bond and its resulting electrical continuity is one of the best measures to prevent the occurrence of corrosion.
Corrosionpedia explains Continuity Bond
A continuity bond is crucial in cases where the bond loss would lead to problems such as corrosion. In order to understand this concept, it is best to start with current. Primarily, alternating current (AC) comes from sources like alternators, generators and power cords, whereas direct current (DC) comes from batteries. Electrical continuity, which covers continuity bonds, is just one of the tests to measure current and voltage.
Nearly all electrical test meters include a test for continuity. Such tests are used to identify if a metal or its component has an existing continuity to the other metal. Essentially, this test determines if components like a rudder, for instance, have continuity with sacrificial anodes. It is very unlikely that corrosion would occur with incorrect wiring. Yet, this is possible since AC wires typically produce electrical currents that can trigger corrosion.
This problem can be resolved by making use of isolation transformers or galvanic isolators. The second option is less expensive, but the first option is a very sophisticated solution in preventing corrosion. Measuring the continuity bond is important, especially in a variety of metals under or immersed in water. Such conditions require proper grounding to prevent wires and metal components from corroding.
There are many reasons why a continuity bond may not form or why a metal component may not connect to the bonding system. This can be failure during the construction process or forgetting to attach a component to the system. In the case of interrupted continuity, the best thing to do is to attach the component to the bonding system. In the case of painted components, these should be inspected regularly to detect bonding problems that may cause damage like corrosion.