Planning a commercial refurbishment? Ring the electrician before the builder

Measure twice, cut once, and draw it first

Builders have an old line about measuring twice and cutting once. A commercial refurbishment needs rather more than careful measurement, and the part that gets skipped is almost always the electrical planning.

Whether you are turning an industrial shed into a restaurant, reworking a retail space to change how people move through it, or remodelling an office so the staff can actually get work done, the electrical requirements are decided by what you intend to do in the room. A builder cannot infer them and should not have to. The output of that conversation is a document: a detailed electrical plan.

What an electrical plan is

The electrical plan, sometimes called a wiring diagram or an electrical drawing, is the electrician's equivalent of the builder's plan. It is a map showing where every piece of electrical equipment goes.

Its value is not the drawing. It is that producing one forces every decision to be made while changing your mind is still free. It tells the fit-out builder what is needed before work starts and settles the questions that otherwise get asked at the worst moment, with a wall open and three trades waiting.

It takes time and it feels like a delay when you are trying to open a business. Winging it feels faster right up to the week it is not.

Plan for the business you are becoming

The single most useful instruction you can give an electrician is to size the plan for where the business is going, not for where it is today. If you are moving premises because you outgrew the last one, assume you will outgrow this one too.

Cabling and capacity put in while the walls are open cost a fraction of what they cost once the walls are closed. Over-catering is cheap. Under-catering is a second refurbishment.

What the plan should set out

• Power points. How many, where, and at what height. This is the most obvious item and the one most often under-counted.
• Lighting design. Specific to the trade and the purpose, not generic. Lighting drives how a diner feels, how a shopper behaves and how staff perform, and asking the electrician for recommendations gets you further than handing over a count.
• Dedicated circuits for IT. Putting computers, servers and point of sale on their own circuits keeps them clear of the motors, fridges and power tools that share a general circuit, which is what causes most of the dips and noise that upset electronics. It is not surge protection. Surge protection is a device, and it is the next item.
• Hot water. Almost every business needs at least one hot water system, and where it goes is an electrical decision as much as a plumbing one.
• Staff room and amenities. Fridge, freezer, coffee machine, kettle, microwave, water dispenser. Bathrooms need lighting, hand dryers and whatever else goes in them.
• Specialist plant. A commercial kitchen, a medical or imaging room, a salon. Make an inventory of every item and where it will sit, and flag anything with non-standard power requirements early.
• Signage and window displays. Easy to forget, and critical to some businesses. If you are repeating what you already have, say so. If you have bigger plans, raise them in the planning phase.
• Audio visual. Meeting rooms, screens, sound. It needs cabling like anything else.

Also worth raising

• Capacity. Will the switchboard cope, and does the supply need upgrading? This is a calculation, not a guess, and it has its own section further down this page.
• Safety switches and surge protection. If the premises has no safety switch, it needs one. The same conversation covers surge protection.
• Code compliance. A refurbishment is the natural moment to bring the rest of the building up to current standards, because it is the only time the walls are open.
• Heating and cooling. Even in a mild climate this is a load that has to be planned for, and it belongs on the drawing whether or not it is in this year's budget.
• Servers and comms. Usually covered when dedicated circuits come up. If it does not come up, raise it.

How to tell whether you need a supply upgrade

New equipment in a refurbished space very often draws more than the old supply was sized for, and the answer is arithmetic rather than opinion. The electrician calculates maximum demand using the method in AS/NZS 3000, from the actual connected load and the way the premises will be used, and compares it with what the existing supply and switchboard can carry.

The connection categories and their thresholds are set by the network operator and they change, so do not take a figure off a website, this one included. Ask for the maximum demand calculation for your premises. Any commercial electrician can produce one, and it is the document that determines whether you are looking at a new switchboard, an upgraded supply, or neither.

Choosing the electrician

Your builder will probably suggest someone, and that suggestion is usually a good one. Getting a second opinion as well costs you an hour.

Three questions are worth asking.

• Do they do commercial work, and specifically commercial refurbishments rather than only new builds? Refurbishment is a different skill. New build is a clean site and a drawing. Refurbishment is somebody else's forty year old wiring, a tenancy that may still be trading, and a surprise behind every second wall.
• Do they work well with builders and other trades? Cross-trade coordination is most of what keeps a programme on track, and an electrician who cannot do it will cost you weeks that never appear on anyone's invoice.
• Do they hold every licence the job needs, at every stage? One business covering the whole electrical scope is faster and cheaper than three, and it means one person is accountable when something does not line up.

Where BH Electrics fits

BH Electrics does commercial refurbishment work across the Douglas Shire and the Cairns northern beaches, alongside fit-out builders and other trades, with our own electricians rather than subcontract labour. The project write-ups on this site are real jobs with the builder named on each one.

Advice on a refurbishment is free and it is most useful early. The worst time to ring an electrician is the week the linings go on.