Alright, welcome back to A Glimpse of Engineering. I’m Caleb Thompson, and as always, I’m joined by Emily Cartwright. Today, we’re going deep into the engineering design process—how a project goes from a vague idea to a finished, compliant switchboard. Emily, you ready to get into the weeds?Absolutely, Caleb. This is the part of the job where you find out just how many questions you didn’t know you needed to ask. Every project starts with gathering requirements, and honestly, it’s never as simple as just reading a spec sheet. You’ve got client specs, Australian standards, lessons learned from past jobs—sometimes even a bit of detective work if the site’s got a history.Yeah, and I remember from our last episode, we talked about how missing a single requirement can snowball into rework or, worse, non-compliance. So, what’s your first move when you get a new project brief?First thing, I’ll pull together all the client documentation—specs, scope of works, any technical queries that have already come up. Then I’ll check what standards apply. For low voltage switchgear, you’re always looking at AS/NZS 3000 and AS/NZS 61439, but depending on the site, you might need to consider a dozen more. And if there’s anything unclear—like, say, the site’s earthing system or short circuit levels—I’ll either send a technical query or, if it’s really murky, push for a site visit. There’s no substitute for seeing things in person.I love that. It’s like being a bit of a forensic investigator. And you mentioned lessons learned—how do you actually use those?Well, we’ve got a design register and a whole folder of previous projects. I’ll dig through those, see if we’ve done something similar, and talk to the engineers who worked on it. Sometimes you find a clever workaround, sometimes you find a cautionary tale. Either way, it’s about not repeating mistakes. And before I get too far, I’ll fill out a Design Self Check Plan—basically a checklist to make sure I’m not missing any gaps in the requirements.So, it’s not just about ticking boxes, it’s about building on what’s worked and avoiding what hasn’t. That’s a theme we’ve hit before—continuous improvement, right?Exactly. And documenting everything as you go, so the next person doesn’t have to start from scratch.Alright, so you’ve got your requirements sorted, you’ve filled in your self-check—what’s next? I know at OFI, there’s a big emphasis on peer review. How does that actually work?Yeah, this is where the Subject Matter Experts come in. Once you’ve got your initial design or even just a concept, you hand it over to someone with deep experience in that area—could be power systems, controls, hazardous areas, whatever’s relevant. They’ll check your drawings, your bill of materials, datasheets, layouts, and make sure you haven’t missed anything from a compliance or technical perspective.So, it’s not just a rubber stamp. They’re actually looking for holes, right?Oh, absolutely. And it’s not always comfortable. Sometimes you get your work handed back with a bunch of redlines or questions. But it’s better to have that happen in the office than on site. Plus, there’s a constructability check—usually with the workshop supervisor or project manager—to make sure what you’ve designed can actually be built with the materials and tools we’ve got. No point designing something that’s impossible to assemble or source.That’s a good point. I’ve seen plenty of beautiful designs on paper that just don’t translate to the real world. So, what kind of documents do you need ready for that SME review?You want your drawings as close to client-ready as possible—even if they’re just redline versions. Datasheets, equipment lists, cable schedules, and a design checklist for that part of the work. The idea is, the SME shouldn’t have to chase you for missing info. It’s all about making the review as efficient as possible.And I guess that’s where the culture of accountability comes in, which we talked about in episode five. Everyone’s responsible for the quality of their own work, but also for helping their teammates catch things before they become problems.Yeah, and it’s not about blame—it’s about making sure the end product is safe, compliant, and buildable. That’s the whole point of the process.So, let’s say your design’s passed the first round of reviews. Now you’re moving into concept development. What does that actually look like in practice?This is where you start turning requirements into something tangible. You’ll generate a load list—basically, what’s going to be powered, how much current, what the peak and diversity loads are. Then you’ll sketch out single line diagrams, block diagrams, maybe a basic power system model. You’ll also start building your equipment list, including major cable runs and any special cooling or heat-rise calculations.So, you’re not just designing for today, you’re thinking about how the system will behave under different conditions, right?Exactly. And you’re estimating the engineering effort, which is huge for project planning. If you underestimate, you end up scrambling later. If you overestimate, you might price yourself out of the job. So, you want to be as accurate as possible, and that means looping back with the SME for another peer check. It’s iterative—design, check, tweak, repeat—until you’ve got a concept that’s solid enough to send to the client for review.And I imagine there’s a lot of back and forth with the client at this stage. Technical queries, clarifications, maybe even a bit of negotiation if something’s not quite standard?Yeah, definitely. Sometimes you have to explain why you’re departing from a standard, or why a certain piece of equipment is the best fit. It’s all about transparency and making sure everyone’s on the same page before you get too far down the track.And you’re still documenting everything, right? Design register, risk register, all that good stuff?Always. If it’s not documented, it didn’t happen. That’s saved me more than once when a question comes up months later.Alright, so you’ve got a concept that everyone’s happy with. What’s the next step—preliminary design?Yeah, this is where you start getting into the details. You’ll take the concept and flesh it out—final load lists, single line diagrams, key equipment selections, cable calculations, and preliminary layouts. If it’s a switchboard job, you’ll also start filling in the User Agreement section of the AS61439 template. That’s basically a checklist to make sure the client’s on board with how the switchboard will be built.So, the User Agreement is like a contract between you and the client about what’s being delivered?Pretty much. It’s a way to lock in the design before you go too far. Any deviations get recorded there, so there’s no surprises later. And you’ll also be prepping for procurement—especially for long-lead items. If you wait until the detailed design is done, you might miss your window and delay the whole project.And I guess this is another point where you’re doing self-checks and SME reviews?Yep, every stage. Plus, you’re filling out the project engineering checklist—making sure you’ve covered all the bases. Once the preliminary design is done, it goes to the client for approval. And you always, always track what you’ve sent with a transmittal form. That way, there’s a record of what was submitted and when.Sounds like a lot of paperwork, but I can see how it keeps things from falling through the cracks. And once the client signs off, you can start locking in your suppliers and getting ready for the next phase.Exactly. It’s all about setting yourself up for a smooth detailed design and, eventually, construction.Alright, let’s bring it home—detailed design. This is where everything gets finalized, right?Yeah, this is the most rigorous part of the process. You’re finalizing all your documentation—power studies, earthing studies, arc flash assessments, detailed schematics, control system design, cable schedules, general arrangement drawings, the whole lot. And you’re making sure everything is compliant with AS61439, which is non-negotiable for switchboards above 125A or with high fault levels.And if you’ve deviated from the original manufacturer’s design, you’ve got to do a full compliance assessment, right?Exactly. OFI uses a pretty rigid approach—if you change something from the standard CUBIC or ELSTEEL design, you have to individually assess each component for compliance. It’s a lot of work, but it’s what keeps the product safe and legal. And you’re also preparing the Switchboard User Documentation, the MDR, and making sure all your cable and product data is up to date in the repositories. That way, everything’s traceable and ready for handover.And I guess at this point, you’re thinking about not just the design, but also how it’s going to be built, transported, and installed. Plinth design, lifting studies, transport requirements—all that practical stuff.Yeah, you can’t just hand over a stack of drawings and walk away. You’ve got to think about how the board will be lifted, how it’ll be strapped down for transport, whether the client’s got the right gear to unload it. Even the friction level of the load matters—like, is it steel on timber or steel on steel? It all gets factored in. And then, finally, you hand over the as-built documentation, redlines, and close out the project. But honestly, by the time you get there, you’ve already set yourself up for success if you’ve followed the process.It’s a lot of moving parts, but it all comes back to that structured process—requirements, reviews, documentation, and compliance. Emily, thanks for walking us through it. Any final thoughts before we wrap up?Just that every stage matters. If you cut corners early, you’ll pay for it later. But if you do the work up front—ask the right questions, get the right people involved, and document everything—you make life a lot easier for yourself and everyone else down the line.Couldn’t have said it better. That’s it for today’s episode of A Glimpse of Engineering. Thanks for tuning in, and we’ll be back soon with more behind-the-scenes stories from the world of engineering and the next phase of our series looking at the design process at OFI. Emily, always a pleasure.Thanks, Caleb. Catch you next time.See you, everyone.

Episodes

Engineering Design – From Concept to Completion