Most people first encounter the question late, usually when a builder asks who is producing the lighting layout. The room has a ceiling plan with circles on it, an electrician who can install anything shown, and an interior designer with a clear view of how the space should feel. Somewhere between those three, a set of decisions has to be made about how much light goes where, and it is not obvious whose job that is.
The short answer is that an electrician makes the installation safe and compliant, an interior designer establishes how the space should feel, and a lighting design consultant determines the quantity, quality and control of the light itself, then documents it so the other two can build it. On a small residential job those roles collapse into one person without much harm. On a commercial fit-out they separate, and the gaps between them are where projects lose money.
The six things a lighting consultant produces
1. A brief that has numbers in it. The starting point is what the space has to do. A restaurant serving lunch and dinner needs two different states from one installation. For example, an office needs a maintained illuminance appropriate to screen-based work under standards such as AS/NZS 1680, while public-realm and exterior projects may be assessed under the relevant parts of AS/NZS 1158. Turning "warm and inviting" into target illuminances, colour temperatures and contrast ratios is the first deliverable, and every later decision refers back to it.
2. A lighting concept. This is where the scheme is designed rather than calculated — which surfaces are lit, which are left dark, where the eye is drawn on entry, how the space reads from the street at night. It is presented visually because it is a visual argument, and it is the stage where changing your mind is free.
3. Photometric calculations. The concept is then verified. Room geometry, surface reflectances, luminaire photometric data and the maintenance cycle go into AGI32 or DIALux EVO, and the output is a set of illuminance results that either meet the target or do not. This is the step that separates a scheme that works from a scheme that looked good in a render. It also catches the expensive problems early: a space that needs forty fittings rather than the twenty-five drawn, or a ceiling height that makes the intended fitting unworkable. The calculation sequence behind it — illuminance target, luminaire count, circuit load, cable and protection — is set out in the engineering behind a lighting design.
4. A specification and a control design. Every luminaire is scheduled with its type, output, colour temperature, beam angle, finish and mounting detail. Circuits are grouped so the space can be operated the way it is used — a lunch state, a dinner state, a cleaning state — and the control system is specified so staff press one button rather than learning a dimming console.
Load, cable sizing and protection are coordinated with the electrical designer under AS/NZS 3000 and AS/NZS 3008, while lighting power density is checked against the applicable NCC Section J requirements.
5. Support through procurement and construction. Substitutions arrive during pricing, and most of them are not equivalent to what was specified. Reviewing an alternative against the photometric requirement rather than the product photograph is routine consultant work, and it is where a schedule holds or quietly degrades.
6. Focus and commissioning. Adjustable fittings arrive aimed at nothing in particular. Somebody has to walk the finished space after dark and aim every one of them, set the scene levels, and confirm the installation matches the design.
What a focus session does
A focus session corrects the small details that can make an otherwise good lighting design feel wrong. For example, a spotlight may initially land on the edge of a dining table rather than its centre or illuminate a wall unevenly. During the session, each adjustable fitting is carefully aimed and dimmed so the finished space looks and feels as intended.
Where the boundaries sit
| Responsible for | Delivers | Answers to | |
|---|---|---|---|
| Lighting design consultant | How much light, where, what quality, how controlled | Concept, calculations, luminaire schedule, control design, focus | AS/NZS 1680, NCC Section J7, the project brief |
| Electrician / electrical contractor | Safe, compliant installation and connection | Installed and certified works | AS/NZS 3000, the certificate of compliance |
| Interior designer / architect | How the space looks and works as a whole | Materials, finishes, spatial arrangement, fitting aesthetics | The design intent and the client |
The overlaps are real and productive. Fitting selection is usually a conversation between the consultant and the interior designer, because a luminaire is both a photometric device and a visible object. Circuit arrangement is a conversation with the electrician. What does not overlap is accountability: when a certifier questions an illuminance level or an energy calculation, one party has the calculation.
Independent specification
A lighting consultant who does not sell luminaires specifies against the brief and the standard. The fitting selected is the one that meets the photometric requirement at the right price, from whichever manufacturer supplies it, and an alternative is assessed on its photometric data.
This is worth stating plainly because free design services are widely available from suppliers, and they are genuinely useful in the right context. The distinction is simply what the recommendation is optimised for. An independent consultancy is paid for the design, so the design is the product.
When a project does not need a consultant
Replacing fittings in a house, relighting a single small room, or a fit-out that reuses an existing compliant layout — an electrician and a good supplier will handle these well, and bringing in a consultant adds cost without adding much.
The threshold is roughly where one of these appears: a space where atmosphere is part of the commercial offer, multiple lighting states from one installation, a compliance obligation that has to be demonstrated rather than assumed, a heritage or public-domain constraint, or a ceiling that will be closed before anyone can test whether the lighting works. Past that point the calculation and documentation cost less than the rework they prevent.
FAQ
Can my electrician do the lighting design?
An electrician installs, connects and certifies the work under AS/NZS 3000, and many are very good at fitting selection for straightforward spaces. What is not necessarily included in the electrician's installation scope is detailed photometric calculation, specification against the relevant lighting standards, lighting control design and NCC energy-compliance assessment.
At what stage should a lighting consultant join the project?
During concept design, alongside the interior design. Lighting positions determine ceiling coordination, and cabling has to be resolved before linings are closed. Joining after the ceiling is set restricts the design to what the existing structure allows.
What does a lighting consultant actually hand over?
A lighting concept, photometric calculation results, a luminaire schedule, layout and mounting details, a control and circuiting scheme, and a focus report after commissioning. The exact set scales with the project.
Do lighting consultants supply the fittings?
Some lighting consultants also supply products. SL Design Consultant operates as an independent consultancy: we specify rather than supply, and procurement normally runs through the electrical contractor or the client's preferred supplier.
SL Design Consultant is an independent lighting and electrical design consultancy in Sydney, delivering lighting and electrical design across commercial, hospitality, retail, heritage and public projects. Our product-neutral recommendations are guided by design intent, technical performance and project requirements.