CT Metering Brisbane: 2026 Cost and Commercial Install Guide
CT metering is the line that separates a small commercial install from a real industrial site. The moment your maximum demand crosses 100 amps per phase, Energex stops accepting direct connected meters. You need CT cores, a metering chamber, a Cat C EWR and a proper switchboard modification. This guide gives you the real 2026 SEQ Sparky pricing for Brisbane CT meter installs, the Energex specifications you cannot skip, the switchboard impact, and what to do when a CT meter fails.
I am Anthony Nuich, owner of SEQ Sparky and a QLD licensed electrical contractor (Licence 90899). We install CT metering for Brisbane Southside cafes, supermarkets, industrial workshops, cold storage and EV fleet sites. Fully insured to $20 million.
CT metering cost in Brisbane 2026 at a glance
Pricing depends on the CT ratio (size), single or three phase, whether the switchboard already has a metering chamber, and the Energex inspection schedule. Here is the real 2026 SEQ Sparky pricing.
| Install type | Typical 2026 cost | Timeline |
|---|---|---|
| 3 phase CT meter to 200A (new commercial) | $2,800 to $4,200 | 1 to 2 days |
| 3 phase CT meter to 400A | $3,800 to $5,800 | 1 to 2 days |
| 3 phase CT meter to 800A (industrial) | $5,500 to $8,500 | 2 days |
| Existing CT meter replacement | $1,800 to $3,200 | Half day |
| Switchboard metering chamber retrofit | $1,800 to $3,500 | 1 day |
| Solar export CT addition (over 30 kW) | $2,200 to $3,800 | 1 day |
Pricing includes CT cores (Class 1 metering grade), secondary wiring, isolation switch, sealed metering chamber, Energex EWR Cat C lodgement, commissioning and Form A compliance. Energex meter is provided by Energex through network charges.
When you need CT metering vs direct connected
- Up to 100A per phase: direct connected meter. Standard for residential and small commercial. Cheaper, simpler.
- Over 100A per phase: CT metering mandatory. Energex will not install a direct connected meter above 100A. CT cores step the current down to a safe level for the meter.
- Bidirectional solar export over 30 kW: CT solution. Standard direct meters cap at this level.
- Bulk industrial or multi tenancy: CT metering preferred. Even where direct could technically work, CT gives more accurate billing and supports time of use tariffs.
Brisbane commercial sites that almost always trigger CT metering: any restaurant with ducted air conditioning, all supermarkets, cold storage facilities, EV fleet charging sites, industrial workshops with 3 phase machinery, medium scale solar exporters.
How CT metering works in plain English
A direct connected meter has your full incoming current flowing through it. At 200 amps that means heavy copper, big terminals, lots of heat and a physically large meter. Past 100 amps the meter becomes impractical.
A CT meter solves this by separating the current measurement from the current itself. Three Current Transformers clamp around each phase conductor. Each CT outputs a tiny secondary current (typically 5 amps) proportional to the primary current. The meter reads the small secondary and multiplies by the CT ratio to calculate the true kWh.
The meter itself is small, cool, and accurate to within 0.5 percent across a wide range. The CT cores are rated for the primary current of your install (200A, 400A, 800A, 1200A etc).
Energex requirements and Cat C EWR
CT metering installs require a Cat C Energex Electrical Work Request. This is one level above the standard residential Cat A and reflects the larger scope and Energex inspection requirements.
- CT specification. Class 1 accuracy minimum (Class 0.5 for billing critical), correct primary rating, correct burden rating
- Secondary wiring. 2.5mm copper minimum, lead sealed at both ends, no joins between CT and meter
- Metering chamber. Sealed enclosure separate from the main switchboard busbars, accessible for Energex inspection
- Isolation. Lockable isolation switch on the supply side of CTs for safe maintenance
- Earthing. CT secondaries earthed at one point only (typically the meter terminal)
- Labelling. CT ratio, polarity dots, phase identification clearly marked
Energex inspects the install on commissioning and signs off before the meter is energised. Failed inspections cost time and money to remediate. We test thoroughly before booking the Energex inspection. Background on the full EWR process is in our electrical compliance Brisbane guide.
Switchboard impact: what space you need
Modern commercial switchboards built in the last 10 years usually include a sealed metering compartment ready for CT installation. Older boards rarely have the space. The retrofit options are:
- Bolt on metering chamber. Separate enclosure mounted next to the existing switchboard. CT cores feed the metering chamber through short cable runs. Cleanest option for older boards.
- Internal compartment retrofit. If the switchboard has spare space, a sealed CT compartment can be built into the existing board. More involved but tidier visually.
- Full switchboard replacement. If the board is old and at capacity, replacing it with a modern unit that includes CT space is often cheaper than retrofitting twice. See our switchboard upgrade cost guide for full pricing.
CT ratio sizing: how we calculate the right size
CT primary rating must be higher than your maximum demand but not so high that the meter sits at the bottom of its accurate range. Typical sizing logic:
- Calculate maximum demand from billing data or load study
- Add 20 to 30 percent headroom for future growth
- Choose the next standard CT rating: 100A, 200A, 400A, 600A, 800A, 1200A, 2000A
- Verify accuracy across the operating range (typically 5 to 120 percent of primary)
- Confirm CT burden rating matches the meter and secondary wiring
SEQ Sparky does a free load study before quoting. We log demand over 5 to 7 days and pick the CT ratio that covers current load plus future growth.
Solar export and bidirectional CT metering
For commercial solar systems above 30 kW the CT meter reports import and export separately. This supports time of use tariffs and the commercial solar feed in tariff. For sites with battery storage the CT meter also tracks charge and discharge cycles.
Bidirectional CT installs add a second set of CTs on the solar export side, plus a more capable meter. Cost addition is $2,200 to $3,800 over a standard CT install.
What is included in a SEQ Sparky CT meter install
- Free demand load study (5 to 7 days of logging)
- CT ratio sizing recommendation
- Class 1 metering grade CT cores (or Class 0.5 for billing critical)
- Sealed metering chamber and lockable isolation switch
- Class 2.5 secondary wiring lead sealed at both ends
- Switchboard modifications or new compartment retrofit
- Energex Cat C EWR lodgement and coordination
- Commissioning testing including ratio and polarity verification
- Energex inspection coordination
- Form A compliance certificate
- Operator handover and labelling
- Optional 12 month testing schedule
CT meter failures and emergency replacement
CT meters fail occasionally, usually from communication module faults or modem failures rather than the metering itself. When a CT meter fails:
- Energex bills the site on estimated demand based on historical data
- Customer arranges replacement through a licensed contractor
- Contractor lodges Cat C EWR for the replacement
- New meter and modem fitted, secondary wiring tested
- Energex inspection and meter activation
SEQ Sparky responds to commercial CT meter failures within the same week. For 24/7 critical sites we offer a priority response option. Same approach detailed on our emergency electrician Brisbane page.
How to choose the right contractor for CT metering
- QLD electrical contractor licence number on every quote
- Public liability insurance certificate (we hold $20 million)
- Experience with Cat C Energex EWR lodgements
- CT metering specific qualifications and recent commercial work
- Free load study before sizing the CTs
- Class 1 CTs minimum (not generic imports)
- Sealed lead wiring and proper metering chamber
- Form A compliance certificate included
For commercial sites also reviewing switchboard capacity or three phase upgrades, see our commercial electrician Brisbane page and the three phase power Brisbane 2026 guide.
Frequently asked questions
How much does CT metering cost to install in Brisbane in 2026?
A standard 3 phase CT meter install for a commercial site costs $2,800 to $4,800 fitted, including CT cores, meter, modem, link cables, isolation switch and Energex EWR. A larger 400A or 800A install for industrial sites costs $4,500 to $8,500. Replacement of an existing failed CT meter sits at $1,800 to $3,200.
When do I need CT metering instead of a direct connected meter?
Energex requires CT metering when the maximum demand exceeds 100 amps per phase (about 60 kVA on 3 phase 400V). Direct connected meters are physically limited to 100A. Any commercial site with serious air conditioning, large industrial machinery, EV fleet charging or solar export above 100A will trigger CT metering.
What is the difference between a CT and the meter itself?
The Current Transformer (CT) is a ring or split core sensor that clamps around each phase conductor. It steps the high primary current (say 400A) down to a small secondary current (5A) that the meter can read safely. The meter calculates total kWh using the CT ratio. Three CTs feed one 3 phase meter.
How long does a CT meter install take?
A standard new commercial CT install takes 1 to 2 days from site arrival. Energex inspection adds 1 to 2 weeks at the end. Replacement of an existing CT meter takes half a day. Power outage on the site is usually 2 to 4 hours during the changeover.
Do I need to upgrade my switchboard for CT metering?
Often yes. CT metering needs space in the switchboard for the CT cores plus the secondary wiring chamber. Older boards without that space need a metering compartment retrofit, which adds $1,800 to $3,500. New switchboards built for commercial sites typically include the CT space.
Who pays for the CT meter and CT cores?
In Queensland the customer pays for the CT cores, secondary wiring and any switchboard modifications. The Energex meter itself is provided and owned by Energex through the network charges. The contractor lodges the EWR with the CT type and ratio so Energex provides a compatible meter.
Does CT metering measure solar export as well as import?
Yes. A CT meter measures bidirectional current and reports import and export separately. For sites with embedded solar above 30 kW the CT meter is the standard solution and supports time of use tariffs.
What happens if a CT meter fails?
Energex bills based on estimated demand until the failed CT meter is replaced. The replacement install is the responsibility of the customer through a licensed contractor. Energex tests the new CTs on commissioning. SEQ Sparky offers same week response on CT meter failures for commercial sites.
Get a fixed price for Brisbane CT metering
If your maximum demand has crept past 100 amps per phase, or Energex has flagged your site for CT metering, get a proper load study and fixed price. I will come out personally, log demand, recommend the CT ratio, and quote turnkey including Cat C EWR and Energex inspection.
Call SEQ Sparky on 0431 110 148 or request a quote through the commercial electrician Brisbane page. Brisbane Southside, owner operated, QLD Licence 90899, fully insured to $20 million.
