Where is Cosine based and what areas do you cover?

Cosine Electrical is based at Waerenga in the North Waikato, between Te Kauwhata and Morrinsville. We cover the wider Waikato and South Auckland — from Manukau down to Te Awamutu, east to Thames, west to Raglan. Drive times from Waerenga: Hamilton 30-40 minutes, Cambridge 40 minutes, Pukekohe 30 minutes, Manukau 45 minutes, Raglan 75 minutes, Thames 60 minutes.

What is the digger operator on the crew thing?

Most electricians sub-contract digging for underground work — second contractor, second quote, second site visit. Cosine has a skilled digger operator on the crew, so for underground jobs we trench our own runs. One quote, one team, one site visit. Note: Cosine is not a registered drainlayer. Wastewater and stormwater scope sits with a licensed drainlayer.

How quickly do you get back with a quote?

Within 24 hours of the site visit. Itemised, in writing, valid 30 days. For smaller jobs we can often give a rough indication over the phone if you text photos of the existing setup.

What does an EV charger install cost?

Standard install with the existing switchboard up to spec is $1,200-$1,800 plus GST plus the charger. Older home needing a board upgrade adds $1,500-$2,500. Long trenched runs to a detached garage on a lifestyle block typically $2,500-$4,500 all-in.

Do you do compliance testing for landlords?

Yes — landlord WOF-equivalent inspections, RCD function tests, written reports with photos and plain-English findings. Insurance-ready paperwork.

Do you work with builders on renovations?

Yes — preferred sparky for several builders across Hamilton, Cambridge and Pukekohe. We walk through with the homeowner and builder before quoting, mark up the plans, and work to the builder's schedule. We don't hold up the next trade.

Can you handle commercial maintenance for property managers?

Yes — scheduled maintenance contracts, emergency callouts, fault-finding, compliance reporting. One number, one paperwork system, no padded packages and no lock-ins.

Do you certify the work?

Always. Every new circuit and every board upgrade gets a Certificate of Compliance emailed through within a day of the job finishing. Required for insurance, future sale and any audit.

What if you cannot fix a fault in one visit?

Some faults like earth leakage on a circuit shared by multiple cables genuinely need a second visit. Day 1 we isolate the faulty section onto its own RCBO so the rest of the house keeps power. Day 2 we test and replace the bad section. We don't punch holes in walls to brute-force the search.

What Does a Switchboard Upgrade Cost in the Waikato?

Kris Goff

7 hours ago

4 min read

Short answer: most domestic switchboard upgrades in the Waikato land between $1,800 and $4,500 plus GST. The board itself is a small part of it. The cost sits in how many circuits need their own RCBO, whether the mains cable and earthing have to be replaced at the same time, and what we find once the cover comes off.

That is a wide range, and we are not going to pretend otherwise. Here is what actually moves the number, so you can work out roughly where your place sits before anyone turns up.

What you are actually paying for

A switchboard upgrade is four jobs bundled together. Knowing which ones apply to you is most of the pricing.

The enclosure and gear. A new board plus an RCBO on each circuit. RCBOs are the single biggest material line - you need one per circuit, not one for the whole house.
The changeover. Disconnecting the old board, terminating every existing circuit into the new one, labelling and testing each one. This is the labour, and it is the bit that takes the day.
Mains and earthing. If the mains cable into the board is undersized, or the earth stake and bonding do not meet current spec, that gets fixed at the same time. It has to be.
Testing and certification. Insulation resistance, polarity, earth continuity, RCD trip times on every circuit, then a Certificate of Compliance for the work.

The four things that push the price up

1. Circuit count

A 1960s three-bedroom house might have six circuits. A renovated four-bedroom with a heat pump, an oven, a hob, a cottage out the back and an EV charger might have eighteen. Each one needs its own protective device. That is the honest reason two houses on the same street can be $1,500 apart.

2. What the old wiring is made of

In older Waikato and South Auckland housing stock - the pre-1970 villas and bungalows around Thames, Paeroa, Huntly and the older Hamilton suburbs - we regularly open a board and find cloth-covered or early rubber-insulated cable coming into it. You cannot terminate degraded cable into a new board and sign it off. Either the affected circuits get re-run, or the scope changes. We will tell you before we start, not after.

3. Whether the mains need upsizing

If you are adding an EV charger, a second heat pump or a workshop, the existing mains may not have the headroom. Upsizing the mains means a new cable from the point of supply and, sometimes, a fuse change at the network end. That is a conversation with your lines company - WEL Networks through most of the north Waikato, Waipa Networks around Cambridge and Te Awamutu, Powerco over the Hauraki side, Counties Energy around Pokeno, Tuakau and Pukekohe.

4. Where the board is

A board on an outside wall at waist height is a straightforward day. A board in a cupboard under the stairs with a wardrobe built around it is not. Access is real money.

Signs your board is due

Ceramic rewireable fuses, or fuse wire in a drawer nearby.
No RCD protection at all, or a single RCD covering the whole house so one fault kills the lot.
The board is full and there is nowhere to add a circuit.
Brown scorch marks, a burnt smell, or a warm cover.
Nuisance tripping that nobody has ever got to the bottom of - that is usually a fault, not the board, and it is worth reading how a sparky actually finds it before you spend money.

A full board of ceramic fuses is not illegal and you will not be forced to replace it. But it gives you no earth-leakage protection, which is the thing that stops a faulty appliance from killing someone.

How we quote it

We come and take the cover off. We count the circuits, check the mains size, check the earthing, and look at what is coming into the board. Then you get a fixed price with the scope written down - including what we will do if we find degraded cable behind it. There is no charge for the five-minute phone conversation first, and we would rather have it than not.

Questions we get asked

How long does a switchboard upgrade take?

Most domestic boards are a one-day job with the power off for a good part of it. Bigger boards, or ones where the mains are being replaced at the same time, can run to two days.

Do I need an RCD on every circuit?

For new and altered circuits, yes - AS/NZS 3000 requires RCD protection on socket outlets and lighting. When we replace a board we fit an RCBO per circuit as standard, because one tripped circuit should not take out your freezer and your smoke alarms at the same time.

Will I get a certificate?

Yes. You get a Certificate of Compliance for the work, and a Record of Inspection where the job requires one. Keep them - your insurer and any future buyer will want to see them.

Can I upgrade the board now and the mains later?

Often yes, as long as the existing mains are safe and adequately rated for the current load. We will tell you straight if they are not.

Getting it priced

We are based at Waerenga in the north Waikato and cover from Pukekohe and Papakura down through Huntly and Hamilton to Cambridge, across to Morrinsville, Paeroa and Thames. Call Kris on 021 466 666, or see the full scope on our mains and switchboards page.