Cable Cleats & Galvanic Corrosion - Ellis Patents Cable Cleats

By Chris Dodds on 2nd January, 2013

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Ellis Patents Cable Cleats

Galvanic Corrosion & Cable Cleats

 

When dissimilar metals are in contact in the presence of an electrolyte, galvanic corrosion occurs. This means that one of the metals will be protected and the other metal will suffer accelerated corrosion.

Although seawater is an obvious electrolyte, all atmospheric moisture acts as an electrolyte to some degree so galvanic corrosion will almost always occur when dissimilar metals are in contact.

However, this may not always be detrimental such as in the case of galvanized steel, where the zinc coating acts as a sacrificial anode and protects the steel it covers, even when the surface is scratched.

Although they are different materials, it is quite acceptable to fasten a stainless steel cleat to galvanized ladder using a stainless fixing because the corrosion resistant properties of stainless steel are brought about by the metal's ability to generate a passive impervious film on its surface, which self repairs in the presence of oxygen.

If the passive layer breaks down (say due to movement between the cleat or bolt and the galvanized ladder) galvanic corrosion will take place but the zinc layer on the ladder will then protect the cleat and its fixing by the same mechanism by which it protects the steel ladder itself.

In the process of galvanic corrosion the more “resistant” metal (in this case the stainless steel cleat) becomes less susceptible to corrosion and the less “resistant” metal (the galvanized steel ladder) becomes more susceptible to corrosion.

However, the ratio of areas of both metals is very significant and because the surface area of the ladder is much greater than the surface area of the cleats the rate of increased corrosion on the ladder becomes negligible.

A good example of the effect of surface area on galvanic corrosion is to look at the suitability of fasteners for fittings on boats.

It would be quite acceptable to use a stainless fastener on a galvanized fitting (the fitting acts as the sacrificial anode and protects the fastener) but unacceptable to use a galvanized fastener on a stainless fitting (the fastener acts as the sacrificial anode and corrodes away at an accelerated rate).

Ellis Patents Cable Cleats, Clamps & Straps
Short Circuit Protection

Ellis Patents are global leaders in the innovation and manufacture of nylon, aluminium and stainless steel cable cleats - EP satisfy the operational requirements of the construction, oil, gas, rail, utilities, wind energy and power generation industries. Holding Power is Ellis Patents guarantee that EP Cable Cleats will contain dangerous short circuit forces - protecting your people, power and plant.

Vital Short Circuit Protection with Ellis Patents Cable Cleats

Ellis Patents are a leading voice in the campaign to have cable cleats reclassified as short-circuit protection devices. A move that would mean cable cleats would be placed on a parallel with fuses and circuit breakers.

"This reclassification makes absolute sense. In the event of a cable fault, the forces between cables reach their peak in the first quarter cycle, which is the point that cable cleats earn their crust. In contrast, circuit breakers typically interrupt the fault after 3 or even 5 cycles by which time, if the cable cleats are underspecified, the cables will no longer be secure, but will be putting vital electrical installations and lives at unnecessary risk," says Paul Nolan UK Sales Manager, EP.

Ellis Patents are world-leaders in the design, test and manufacture of Cable Cleats for low, high and extra high voltage cable retention and support.

 

Video: Ellis Patents Cable Cleats Short Circuit Test

 

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Category:  Cable Cleats & Cable Ties

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