Quite frequently encountered is corrosion of a connector shell that serves as both a physical coupling and a current carrying element (usually a ground return). This leads to a breakdown when erosion of the contact area produces higher resistance and accelerates the corrosion process. Eventually so much material is lost from the mating contacts that the connector runs hot, in some cases so hot that it destroys itself.

 

Assuming that the connector cannot be replaced with a type more suitable for the climate, and that the connector is still functioning, the usual solution is to clean all traces of salt corrosion from the connector and re-assemble it. The final step may be enclosing it in such a way as to prevent the entry of the contaminants. This may consist of coating the connector body with a high viscosity silicone grease and placing it in some sort of protective sleeve which will prevent the grease from being eroded away. However, because of the potential for silicone-induced problems the preferable method would be to use a layer of self-fusing tape followed by layers of vinyl tape and vinyl coating as mentioned later.

 

Silicone greases can introduce another mode of connector failure, especially when exposed to salt – a silicone compound can combine with the salt to form a hard film of sodium silicate that is non-conductive and difficult to remove without damaging the connector. Even where silicone-based water-excluding gaskets are employed in the connector design, migration of the ethyl and methyl-silane based oils that are often added to the silicone rubber as softeners can cause problems. These are usually encountered where a connector is crimped to a cable.

 

 Many physical failures take place because salt water has penetrated that part of the connector where the wires are crimped or soldered onto the pins. Quite apart from the electrical effects of the corrosion products, these products frequently occupy much more volume than the metal upon which they feed.

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Occasionally enough pressure can be generated to rupture a connector shell. Before this stage, a connector may be jammed or “locked up”, unable to be normally disconnected.

 

Sometimes it is necessary to use a supplementary means of cable/wire strain relief to minimize the effects of wind-induced vibrations in the cable, which can cause a "grinding" action between the two halves of the connector.

 

Another type of failure results from exposure of the connector to unusual corrosive liquids or gases not normally encountered in the environment but which might be generated, from time to time, by other failures in the operating area.

 

This includes corrosion-inducing chemicals liberated from connector components subject to overheating, which can lead to thermal runaway involving current carrying contact-to-wire junctions. It must be remembered that the conductors and insulators used in connectors have their own vulnerabilities to failure, but once compromised, one can weaken the other.

 

In many connectors carrying radio frequency signals, it is necessary to have conductors and insulators dimensioned so that the electrical impedance of the connector is the same as that of the wire. A mismatch can cause RF reflections in a transmission system, which can reduce the effective radiating power of a transmitter or diminish received signal strength. Insulation leakage can cause unacceptable loss or modification of the signal caused by line reflections (e.g., ghosts or detail blurring in cable TV).

 

This simple concern can degrade the performance of a radio communication system, a GPS or Loran, or even a radar system to an unusable condition!

 

Where the RF impedance is not a consideration we still have to deal with losses in or on the electrical insulation. Excessive leakage across the insulation will result in heating in high-power applications, insulation breakdown in high-voltage applications. or signal leakage in multiple-pin control circuits. None of these are acceptable, and the consequences range from destruction of the connector to fire hazards and even consequential damages (legally speaking) due to failure of a process-control, alarm, or communications system.

 

The introduction of corrosion products into the gap between the connecting pair can also result in unwanted rectification effects (many corrosion products can act like crude semiconductors) which can produce strange modulation distortion of the signals or even introduce spurious signals derived from the rectification of RF (including fast rise time digital signals) present in the environment. Generally, this is characterized as excessive sensitivity to "electronic smog".