Corrosion limits steel enclosures

Specifying a high-quality paint finish for sheet-steel enclosures which are to be used outdoors may not be enough to prevent costly damage from rust and other forms of corrosion.

According to Brian O'Donoghue, of Sarel, who is the current Chairman of GAMBICA's enclosure group, specifying a high-quality paint finish for sheet-steel enclosures which are to be used outdoors, or in other demanding environments, may not be enough to prevent costly damage from rust and other forms of corrosion.

"It's quite usual for users to buy excellent, well finished enclosures, and then cut holes in them to mount, for example, instruments and switches", said O'Donoghue.

"What they often forget is that the edges of these holes are no longer protected by the paint finish, and it is these exposed edges which give corrosion a toehold.

After a surprisingly short time, this corrosion can spread, seriously damaging the integrity of the enclosure".

One solution to this problem is to prime and paint all exposed metal surfaces after the holes have been cut, but this is costly and time-consuming, and it is often entirely impractical when work is being carried out on site.

O'Donoghue proposes that a much more cost-effective and certain solution is to specify GRP enclosures in the first place.

"No additional finishing is required for holes in GRP enclosures", he states, "and the GRP material from which they are made is inherently corrosion-proof.

There's also another important benefit - drilling and cutting GRP doesn't produce conductive or magnetic swarf.

With steel enclosures, this swarf can cause endless problems if it finds its way into electrical or electronic equipment".

UK enclosure users often ignore the benefits of GRP because they believe that GRP enclosures are not as strong as their steel counterparts.

In fact, good-quality GRP products have IK (impact protection) ratings at least as good as those for steel boxes.

In addition, the suitability of GRP products for use in tough environments is amply demonstrated by their widespread adoption throughout mainland Europe for demanding applications which include traffic light control, railway signalling, telecommunications and cable television.

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