Challenging designs

Sir Sean Connery, most famous for his award-winning portrayal of James Bond, once said “there is nothing like a challenge to bring out the best in man.” These are wise words as we all continually face our own challenges, throughout every aspect of life. 

Here, Ian McWha, key account manager at industrial systems integrator Boulting Technology, explores the importance of recognising and overcoming challenges when designing a switchboard. 

When plant managers look to install a new switchboard in their facility, they are often presented with a range of challenges that they must address. Identifying these challenges as soon as possible is imperative to the success of the installation and the functionality of the switchboard. If not addressed, these issues can have drastic consequences, causing production downtime or even damage to other systems and employees.  

Design challenges
Each facility is unique and as such will have its own design requirements, dependant on the function of the plant. 

Many plants have limited space that they are keen to maximise, so the footprint of the switchboard needs to be as small as possible, while ensuring its integrity is not compromised.

Boulting Technology’s designers are experienced in creating bespoke systems that meet client specifications, particularly in space-short environments. Bespoke MCC designs include, integrated back to back systems with shared riser and main distribution bars, custom made U shape centres, L shape units that fit round corners and bridges that extend above equipment and wall partitions. 

The specific needs of each job may also present additional challenges that the design engineer must be aware of. When working with pumping stations for example, a switchboard may be required to be near water. In these cases, the ingress protection (IP) rating, which classifies the degrees of protection provided against solid objects, dust, and water must be adhered to. 

As challenges are often individual to a facility, a unique switchboard may be the answer. Bespoke solutions such as Boulting Technology’s can make the most of limited space or other restrictions, while meeting client specifications exactly. 

Maintenance 
Forward planning is essential when installing new equipment, especially when establishing a regular maintenance programme. Planned and predictive maintenance is crucial to keep machinery working efficiently for as long as possible, avoiding production downtime. To solve this, plant managers should work closely with the switchboard manufacturer to develop a robust maintenance programme. 

Boulting Technology offers an all-encompassing maintenance solution, which includes a comprehensive survey that assesses control systems across a facility. An initial online survey assesses areas, such as obsolete parts, equipment life cycle and efficiency. 

From the survey, a series of multi stage recommendations provide a hierarchy of risk, allowing plat managers to focus on high risk critical systems in the first instance and implement an appropriate plan of action. 

Safety
Not properly addressing design challenges can cause safety issues. For example, it is essential that the switchboard has the correct rated short time withstand rating. This is the rating of current that the assembly can withstand for a set period of time without the aid of a short circuit protective device (SCPD). The short time withstand rating, used by engineers to determine the ability of the assembly to protect itself and other devices, is made up of two parts: the fault current rating in kiloampere (kA) and the duration time.

Manufacturers also need to be aware of the prospective short circuit current (PSCC) or fault current. The PSCC is the highest electric current which can exist in a system under short-circuit conditions. 

While engineers should always be aware of the PSCC, specific applications such as when operating transformers in parallel, can present dangerous situations if not managed correctly. 

Legislation, such as BS EN 61439 is the first step to ensuring switchboard safety. BS EN 61439 is a mandatory standard for all low voltage switchboard assemblies (LVSAs) and helps the manufacturer and plant manager ensure the board achieves acceptable levels of performance, safety and reliability. 

It is important to choose a manufacturer and integrator which understands the relevant legislation, how to meet them and how to ensure the product is safe, while also meeting customer requests and requirements. 

While meeting legislation standards is important, it does not automatically mean the switchboard is fit for the desired purpose. Safety requirements can easily be met without the equipment meeting client specifications or even working correctly. Legislation should be one of many considerations when installing new equipment.  

Thinking outside of the box means design challenges can not only be overcome, but can become useful, resulting in bespoke ideas and revolutionary products. This is just as true for engineers designing industrial products such as low voltage switchboards, as it has been throughout the brilliant Sean Connery’s life. 

Changing industry standards: one year on

Pat McLaughlin

In 1998, Google was founded, the first Apple iMac was introduced and the legendary Windows ’98 was released by Microsoft. In a less glamorous but equally important corner of industry, a new commission was being formed to revise the complex IEC 60439 industry standard, which governed the safety and performance of electrical switchgear assemblies. Although Windows ‘98 has long been consigned to history, the new industry standard – BS EN 61439 – only became mandatory on November 1, 2014. 

One year on, Pat McLaughlin, Boulting Technology’s Operations Director, evaluates how original equipment manufacturers, panel builders, electrical engineers, consulting engineers and contractors have been affected by the new BS EN 61439 standard.

Why a new standard?
In a market where the demand to optimise and reduce costs blends heavily with higher needs for assembly flexibility, the introduction of a new set of standards was needed to  guarantee the performance of Low Voltage Switchgear Assemblies.

Switchgear and Control Gear assemblies are multifaceted and have an endless number of component combinations. Before the introduction of the new standard, testing every conceivable variant was not only time consuming and costly, but impractical.

The intricate character of assemblies also meant that many did not fit into the previous two testing categories: Type Tested Assembly (TTA) and Partially Tested Assembly (PTTA). For example, panels which were too small to be covered by TTA and PTTA fell outside the standard. Finally, in the case of a PTTA, ensuring the safety and suitability of a design was often dependent strictly on the expertise and integrity of the manufacturer.

Design verification

The Boulting Power Centre

The major change introduced by the new BS EN 61439 standard refers to testing. It states that the capabilities of each assembly will be verified in two stages: design verification and routine verification. This means the new standard completely discards the type-tested (TTA) and partially type-tested assemblies (PTTA) categories in favour of design verification.

Although BS EN 61439 still regards type testing as the preferred option for verifying designs, it also introduces a series of alternative routes to design verification.

The options include using an already verified design for reference, calculation and interpolation. The BS EN 61439 standard specifies that specific margins must be added to the design, when using anything other than type testing.

One of the main benefits of the new design verification procedure is its flexibility. Under the old BS EN 60439 specification customers would demand a Type Test certificate for each assembly particularly Incoming Air Circuit Breakers, which was very expensive and time consuming.

The new standard allows users and specifiers to pertinently define the requirements of each application. Annex D of the BS EN 61439 standard provides a list of 13 categories or verifications required, what testing method can be used and what comparisons can be made. In order to optimise testing time, the standard allows derivation of the rating of similar variants without testing, assuming the ratings of critical variants have been established by test.

Dividing responsibility
The second major change implemented by the new industry standard refers to the responsibilities of each party involved in the design, test and implementation of low voltage switchboard assemblies. Unlike BS EN 60439, which stated the OEM or the system manufacturer was solely responsible throughout the testing programme, the new standard divides the responsibilities between the OEM and the assembly manufacturer, or panel builder.

The new standard recognises that several parties may be involved between concept and delivery of a switchboard assembly. The OEM is responsible for the basic design verification. In addition, the assembly manufacturer is meant to oversee the completion of the assembly and routine testing.

For innovators like Boulting Technology, the new BS EN 61439 has brought more freedom and flexibility when designing switchboard assemblies. For example, Boulting Technology has designed and launched the Boulting Power Centre, a range of low voltage switchboards, which are available in 25kA, 50kA, 80kA and 100kA, fault ratings, and up to 6300Amp current ratings.

Although change is never much fun, it’s what technology and industry are all about. If this wasn’t the case, we would all still be using Windows 98 or the indestructible Nokia 5110.