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 a switchboard upgrade cost?

A straight switchboard upgrade in an average three-bedroom Waikato house is typically $1,500-$2,500 plus GST for board and labour. Push-ups: old cable failing insulation tests, mains upgrade needed (lines company involvement), asbestos in the meter-box backing board common in 60s and 70s houses. Everything flagged in the written quote — no surprises on the invoice.

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.

EV Charger Install at Waerenga — What You Need to Know

Kris Goff

Jun 18

2 min read

EV Charger Install at Waerenga — What You Need to Know

Call Kris on 021 466 666

If you're at Waerenga or anywhere across the North Waikato lifestyle belt — between Te Kauwhata, Morrinsville and the back-road country in between — adding an EV charger to the house or shed is a job we're set up for as a local. Our base is here. The trucks are parked here. Most of the EV charger jobs we do at Waerenga, Mangatāwhiri or the surrounding rural blocks are same-week turnaround because we're already in the area.

What an EV charger install actually involves

Check the switchboard. A 7kW single-phase charger pulls 32 amps continuously while charging. Many older boards weren't sized for that on top of existing load.
Run a dedicated circuit — 6mm or 10mm cable depending on run length, on its own RCBO at the switchboard.
Mount and connect the charger at the agreed location.
Test, certify and demonstrate. Certificate of Compliance issued.

What's specific to Waerenga and the surrounding lifestyle belt

The charger usually goes on the shed or detached garage, not the side of the house. That means a trench from the main switchboard, often 20-50 metres across the section.
We trench our own runs. Digger operator on the crew, so the underground cable from board to charger location is one job — no second contractor.
Sub-mains are often needed. If the shed already has a sub-board, we tee the charger circuit off that.
Two-EV households are common out here. Provision for a second charger from day one — cheaper to oversize once.

The charger options

Tesla Wall Connector, Wallbox Pulsar Plus, EVnex, Schneider EVlink. We install whichever charger the customer wants.

What it costs

$1,500-$2,500 plus the charger itself. Longer trenched runs (more than 20m) push that higher.

Call Kris on 021 466 666

Easiest if you can send a photo of your switchboard and where you want the charger to sit.

EV Charger Install at Waerenga — What You Need to Know

EV Charger Install at Waerenga — What You Need to Know

What an EV charger install actually involves

What's specific to Waerenga and the surrounding lifestyle belt

The charger options

What it costs

Call Kris on 021 466 666

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