POWER
Why take a chance with Safety Critical items? Making the Right Connection By Steve Downing,YEG
To some people one power cord might seem very much like another. However in reality power cords come in a wide variety of lengths, colours and cable types. They will also have one of many different national plug types and connectors depending on the end use of the cord. So they are more complex than they might first appear to be. It becomes increasingly important to ensure that the correct specification is used for each application. If it is to connect to a socket outlet
Steve Downing asks whether budget power cables are a worthwhile investment.
then it is essential to ensure that the correct plug/fuse type is specified for that country and application. Similarly, the connection of the cable to the connector at either end of the jumper cord is a critical issue. Accidentally unseating or unplugging
a power cord can seriously affect the operation of a system. However, the chances of the connector becoming casually dislodged are minimised if the connector is manufactured to an approved standard. The style of the connector and the terminals that
are fitted can vary dramatically from manufacturer to manufacturer. So it becomes essential to ensure that the connectors are manufactured to the relevant approved standard.
Non-Approved Cords During the last year there have been many examples of non-approved cords arriving into the UK. It would be unfair to say that all of these cords would have potential safety issues as this is just not the case. As an example, many of these cords may not have the necessary approvals for the UK but have been approved for use in other countries. This does not mean they are unfit for purpose, but they have not been tested by BSI or ASTA’s strict standards for the UK market. Some cords may also show the required approval marks on the connector but cannot be backed up with current approval documentation from the manufacturer, so be aware if you are basing your purchase on just a sample alone. There are many other potential
issues with non-approved cords that may not be easily detectable, which is why it is essential to request the appropriate approval documents for any cords that are bought and to ensure that plug, connector and cable are marked with the appropriate approval marks.
Essential Cord Requirements There are certain basic steps that should be followed in the construction of a safe and reliable power cord. Firstly, the plugs or connectors must be in good condition and correctly wired and correctly fused where appropriate. They must be adequately rated and constructed for their application. The cable should be appropriately rated and marked to carry the required current. To achieve this means that it should be unknotted, unmarked and adequately insulated, free from visible damage. The cable must be correctly connected and secured inside the plug or connector. When the cable is being connected
to the plug, it is essential that the core conductors are not marked or nicked when removing the cable’s outer insulation. It is also important that a minimal amount of core insulation is removed when making the connection to the terminals of the plug or connector. All manufacturers will take their
own view as to the level of product and electrical safety that they require their cords to meet. To some, the relevant standards will be seen as a minimum, whilst other factories will build a higher level of compliance into their products and manufacturing processes. When raw material costs are so high, is it worth the risk to source cables from a supplier that works to the minimum in terms of copper stranding in its cable? Do you find a supplier that takes a risk by using the minimum level of outer insulation for its cables? It may be more cost effective in the short term, but it may cost your business in the future. Is it worth taking a chance?
20 NETCOMMS europe Volume II Issue 4 2012
www.netcommseurope.com
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