Advertising Feature Cover Story Electrical safety and efficiency
The aim of every electrical installation should be to reduce the number of workplace electrical incidents and down-time to zero. Connector specialists, MARECHAL, explain how electrical engineers can balance the trade-off between cost, safety and long term reliability in applications ranging from a motor disconnect socket to a full ATEX rated installation
or specifying electrical engineers, aiming for zero electrical incidents and unplanned down-time means delivering electrical safety despite tight budget and space constraints. It also means minimising connection and disconnection times when the machin- ery is in operation or undergoing main- tenance. Every decision is important and presents its own trade-off between cost, safety and performance.
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Often these decisions are not straight forward. Part of the installa- tion may, for example, need a non- standard voltage or operate in a harsh working environment. The key to find- ing a cost effective solution to these challenges often lies in the choice of the right electrical connectors.
Conforming to the law
Basic connector design parameters are covered by current standards but not all industrial applications conveniently line up against these standards. The operating environment may be hotter, wetter or colder - cables may be run- ning at or close to their maximum rating and increasing equipment tem- peratures. Control signals may also need to be combined with power con- nections. Other common non-standard parameters can include current ratings above 125A, as well as the need for multi-contact connectors and ATEX rated connections and hardware. Connectors which are certified to European standards provide electrical engineers with a known level of mechanical performance such as the ingress protection (IP) and shock (IK) rat- ings for operation in wet and harsh envi- ronments. By specifying a connector IEC/NF EN 60309-1 and EN 60309-4 with an integral switching device and an automatic and immediate IP rating on connection and disconnection, the engi- neer can be confident that the connec- tion will protect the operator and maintenance teams from electric shock, which includes extension leads.
The inside story However, the electrical performance of the connector and its design flexibility are also crucial in ensuring that the installation can meet the specific demands of each project during the
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installation and ongoing operation. It is especially important to consider the contact technology of the connector which can affect the overall perfor- mance, efficiency, long term reliability and safety. For example, brass pin and tube contacts are prone to oxidisation and are not suitable for load breaking, particularly in overload conditions. This can compromise both their long term reliability and safety. In comparison, the silver nickel tipped spring loaded butt contacts in MARECHAL’s Decontactor plug and socket outlets provide a much higher and constant electrical perfor- mance and long term reliability. Crucially, they also offer a load break capability, even in overload conditions, and withstand frequent overloads with- out welding. This makes them the per- fect substitute to hard wiring.
Safety fast
In emergency situations, the immediate and safe disconnection of electrical equipment can mean the difference between life and death. The butt con- tacts in Decontactors guarantee safe dis- connection with a single press of the quick release button. This means that they can be quickly and safely discon- nected by staff who have absolutely no electrical knowledge or skill.
Equipment fitted with Decontactors can also be connected or replaced quickly and safely by non-electrical personnel. The speed and simplicity of connecting and disconnecting Decontactors also helps to minimise maintenance down-time.
The inherent flexibility and com- pactness of the decontactor design means that the specifying engineer can match the mechanical and electrical parameters of each individual installa- tion in the smallest possible space.
Standard Decontactors would typi- cally be specified for installations with a current range of up to 250A, whilst high performance plugs and socket outlets, rated from 250A to 600A 1kV, would be specified for heavy duty applications such as genset connec- tions, quarrying and tunnelling equip- ment, ship to shore leads and single core high power cable extensions. The choice of GRP or metal housings, as well as flexible contact and terminal configurations enable Decontactors to be used in applications ranging from low risk environments, right up to ATEX rated installations. Electrical and mechanical interlocking is included as standard on all versions.
Decontactors which are rated above 16A are equipped with a safety shutter, in the same way as domestic socket out- lets are shuttered for child protection. Decontactors can also be configured to meet non-standard specifications without compromising on safety.
Left and below: with MARECHAL Decontactor plugs and socket outlets, the engineer can be confident that the connection will protect the operator and maintenance teams from electric shock
Together we can
The combination of the inherent safety and flexibility of Decontactor technology, with technical support and a ‘can do’ attitude from the manufacturer, MARECHAL can guide even the most challenging application to the right bal- ance between cost, reliability and safety. The aim of every installation, from the most basic connector to a complete ATEX rated tunnel installation is the same - to reduce the number of work- place electrical incidents and unplanned down-time to zero in the year 2013.
MARECHAL
www.marechal.com/en contact@marechal.com T: 01244 851926
Enter 200 DECEMBER/JANUARY 2013 Electrical Engineering
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