Lighting Design Process 1.
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Electrical design
It is crucial for retailers to have complete electrical drawing packs and full specification data, in digital form, for all our fixtures so that we can make swift and accurate design, development and procurement choices. Supporting documentation is also essential to meet increasingly demanding Health & Safety requirements and to protect customers, our business, and our suppliers.
Design Format
The following is a list of the minimum information required to complete electrical technical drawing sheets. All drawing dimensions, notation & information must be legible when printed on A3 paper size.
All sheets must have a drawing boarder that includes:
- Display code
- Project name
- Drawing description
- Drawing number
- Drawing creation date
- Drawing revision (in ascending alphabetic order, initial drawing issue must be revision ‘A’)
- Scale
- Sheet number & total number of sheets in the drawing pack
- Supplier name
- Suppliers address and telephone number and website
- Drawn by
Third party and ‘off the shelf’ items must be clearly identified and marked with the appropriate supplier details, including:
- Supplier name
- Item description
- Reference number
General Electrical Assembly drawings
The drawing provides details on how all components are connected and installed either within the display or standard alone. A template is available within the dc guide and includes:
- Item number
- Description
- Manufacturers name
- Manufacturers code
- Quantity
- Installation instructions
- Safety instructions & Warnings
- Total load in Watts
- Display size in m2
- Polarity
- Specification of cables
- Standard of electrical components
Component Electrical Assembly drawings
The drawing provides details on how components are built and must include all sub-component used in the assembly. A template is available within the dc guide and includes:
- Item number
- Description
- Manufacturers name
- Manufacturers code
- Quantity
- Installation instructions
- Safety instructions & Warnings
- Total load in Watts
- Display size in m2
- Polarity
- Specification of cables
- Standard of electrical components
Circuits
Reductions in cable size or current require fuse protection. Every display should be divided into circuits to:
- Avoid danger and minimise inconvenience in the event of a fault
- Allow safe inspection, testing, and maintenance by a responsible person such as a store manager or nominated duty holder
- Prevent unintended risk of injury due to indirect energising of a circuit that is intended to be isolated.
Electrical Zones
To allow for standardisation of sub-components, circuit types have been divided into 4 electrical zones. This allows the following benefits:
- Reduction in sub-component variation and stock
- Reduced impact of design variations
- Faster installation process
- Easier maintenance
Key considerations
Thermal Management
All electrical equipment generates heat so consideration should be given to the effect of exposure to extreme temperatures. Heat has a degrading effect on electrical components, and poor design can lead to:
- A shortened product life span
- Potential safety hazards
- All heat-generating equipment such as LED drivers and LED modules should be mounted on properly-designed heatsinks to protect against catastrophic failure caused by over-heating.
Access
Electrical equipment needs to be easily accessible for inspection, testing, maintenance and repair. Ensure that access is not significantly impaired by the shop-fitting, displays or signage.
Access to sockets should be restricted or limited to ensure store staff do not misuse them or allow them to become overloaded.
Cables
- Ensure that cables are not constricted or bunched. Cables must be over-length by approximately 10% to ensure they are not taut and electrical connections not strained as this can cause reliability issues and potentially failure.
- Consideration must be given to the specific bend radius of cables to ensure that the cable is reliable and robust over the life of the furniture. This must be factored into the electrical design during the furniture design stage.
- The design should provide adequate cable management and protection from damage. Cables need to be held in place with appropriate mechanical fixings so they cannot snag or be caught on sharp edges or moving parts.
- Provide appropriate cable restraints within the shopfitting displays. Pay special attention to the mains-in lead and connector leads.
- Use cable restraints that comply with the cable manufacturer’s recommendations
- All connections must meet pull force requirements, as specified in the current version of the British Standards.
- Do not install or include redundant conductors in connectors or equipment.
- The selection of the appropriate cable is critical to the integrity of the electrical circuit and the following should be taken into consideration:
- The current carrying capacity of the cable
- The number of cores
- The type of sheathing – PVC, LS0H
Life Expectancy
The electrical designer needs to consider the life expectancy of components and subcomponents. This will vary depending on whether the display is permanent, semi-permanent, or temporary, as well as the type and quality of components used.
The life expectancy of the electrical components, particularly LEDs, has an impact on the type of subcomponents that can be used.
The electrical designer should establish the difference between expected life, warrantied life, and likely hours of usage, and consider how the choice of components will affect the cost.
Connectivity
The electrical systems must be modular and inter-connectable rather than hardwired as this will ensure that the system is easier to install, maintain, and repair.
Connectors should be:
- Rated to the maximum designed fault condition of the circuit
- Pre-wired or assembled by a competent manufacturer using crimped ferrule terminals
- Designed for multiple application, including wire-to-panel and wire-to-wire
- A lockable type wherever possible
Components
Where possible make use of dc approved, standardised components as this:
- Reduces design time
- Reduces purchasing costs
- Accelerates the approval and certification process
When using these components, designers must work to the manufacturers’ guidance including operating temperatures, fixing methods or locations
The use of commonly used electrical components has many benefits:
- It ensures that electrical standards are followed
- It reduces design variations, and so allows purchasing teams to gain better value through volume buying
- It means maintenance teams can carry less spares and complete work more promptly.
- It helps provide a consistency of lighting across a production run and families of furniture
Purchase Costs & ROI
To keep purchase costs down, the designer should perform research and due diligence on products and suppliers. It is important to specify exactly the performance requirements that the products need to meet. Quotations should be obtained from multiple sources.
The cost of similar products can vary a lot, but the key factors to consider are:
- Costs within the supply chain (from manufacturer via exporters, distributors, etc.)
- Perceived value of the product. Is it a luxury item or a functional item?
Typically, the largest ongoing costs relating to store interiors and display equipment are:
- Energy consumption
- Maintenance of electrical devices.
It is important to review all associated costs before selecting equipment.
The following chart shows a breakdown of the main cost considerations, including the lifespan of the product, its expected usage and frequency of replacement.
An example of the calculations for determining for return on investment (ROI) has been included.
Cost considerations
Isolation
All display, signage and shop fit equipment needs to be isolated in the event of failure.
It is the responsibility of the electrical designer to determine where the isolation points are within the store and that store staff and user know the points of isolation.
The electrical contractor has a responsibility to provide clear identification of isolation points that must indicate:
- The means of control/isolation of the equipment
- The specific location of the control/isolation
- Whether there are any backup power supplies connected to the circuit that may still be live even after safe isolation. (Examples of backup power supplies include batteries and UPS.)
- The notice of location and use must be legible, easy to read. and be presented on a durable, tamper-proof material so that the notice remains legible for the life of the equipment.
The manufacturer of the equipment has a responsibility to ensure that it is immediately obvious to the responsible person where the point of isolation is for each electrified display. The location of each control/isolator should be indicated in such a way that no confusion should occur.
Where the point of isolation is not immediately obvious, the manufacturer must provide suitable documentation/drawings/diagrams to clearly indicate the location of the point of isolation. This documentation should be readily available to all in-service shop staff and kept up-to-date by a responsible person (for example, a store manager or nominated duty holder).
When electrified display units are replaced, the responsible person should check the accuracy of the documents. They need to make sure that the documentation is kept up-to-date and accurately describes the location of the isolation points.
Maintenance and Installation
For maintenance and installation, consider the following in the design:
- Fixings
- Installation Instructions
- Maintenance
- Onsite Work
- Fixings
Installation Instructions
For each display, it is necessary to provide installation instructions that are easy to understand. The instructions should include mechanical fixing and electrical connection points as well as the electrical load capacity.
Maintenance
The aim must be to keep maintenance to a minimum. Having spare fuses to hand can help to prevent the need for re-visits, especially when the fuses are specific to the equipment.
Onsite Work
The need for onsite work should be kept to a minimum. Display units should be designed and manufactured so that they can be installed and maintained with minimal need for onsite work. Connections to the mains power supply should be through a flexible cables and connectors to avoid hardwiring.
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