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Energy Meter Sizing Calculator

Which 3-phase energy meter do you need for your factory, office or data centre? Enter connected load, peak current, and circuit count — get a CT rating, a meter count, and a cloud connectivity plan.

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Recommended product
Titan (3-phase CT)
Class 0.5S, DIN rail, WiFi + Ethernet + RS485
Main incomer CT rating
1000/5 A
Smallest standard rating with ≥20% headroom over 800 A peak (needs ≥ 960 A). Class 0.5S CTs, ring (solid-core) or split-core.
Meters required
12units
Total facility load
500kW
Use a mix of WiFi and Ethernet depending on panel location; MQTT to the Energy Intelligence Platform handles aggregation.
For rapid audits or temporary deployment, specify Titan Audit — same metrology engine, with split-core CTs that clamp on live conductors (no shutdown).

How this works

Sizing a 3-phase energy meter comes down to three decisions: (1) the CT rating for the main incomer based on peak current; (2) the number of meters based on how many circuits you want visibility on; (3) the communication architecture — WiFi is sufficient for under 20 meters, MQTT over the facility network is cheaper at 20+ meters. For the full specification and connectivity checklist, see our 3-phase energy meter buyer's guide.

The Titan 3-phase smart energy meter covers the range: 100 / 200 / 400 / 600 / 800 / 1000 A CTs (5 A secondary, Class 0.5S), Class 0.5S accuracy, WiFi + Ethernet + RS485 all built in. For audit use or temporary deployment, the Titan Audit variant uses split-core clamp-on CTs — zero-downtime install.

Frequently asked questions

Two decisions: (1) CT rating on the main incomer — match the expected peak current with at least 20% headroom (Titan CTs come in 100, 200, 400, 600, 800 and 1000 A, 5 A secondary); (2) number of meters — one on the main incomer plus one on each major feeder you want to monitor separately. Most facilities start with 5–15 meters and expand.
No — only on circuits you want to analyse separately. A typical factory deploys one meter on the main incomer (for bill reconciliation + total load tracking), one per major system (compressor, HVAC plant, chiller plant, lighting feeder, production lines), and optionally one per tenant or cost centre. Over-metering is common; start with the 10–15 biggest loads.
Pick the smallest CT rating that gives at least 20% headroom over your expected peak current. For a main incomer drawing 600 A peak (needs ≥720 A), use an 800/5 CT. For a 150 A motor feeder (needs ≥180 A), use a 200/5 CT. Titan uses external Class 0.5S CTs with a 5 A secondary in 100, 200, 400, 600, 800 and 1000 A ratings — ring (solid-core) or split-core — specified with the order. Above 1000 A, talk to us.
With split-core CTs, the CTs themselves clamp around live conductors without disconnecting them. With ring (solid-core) CTs you need a shutdown to thread the CT over the conductor. Titan can use either; Titan Audit always uses split-core CTs for zero-downtime install. Otherwise, schedule a ring-CT install during a planned maintenance window.
Same Class 0.5S metrology engine. Titan is a fixed DIN-rail meter that uses ring (solid-core) or split-core CTs (best for long-term sub-metering). Titan Audit is portable and uses split-core clamp-on CTs only for zero-downtime deployment (best for audits, temporary monitoring, or retrofits where shutdown is impossible). Both share the same app, data platform, and cloud backend.

Related pages & tools

Industrial Energy Monitoring

Circuit-level monitoring for plants and process loads — what the meters you just sized feed into.

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Building Energy Monitoring

The same measurement for offices, malls, hotels and campuses — HVAC-dominated loads and tenant supplies.

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Multifunction Meter (96 × 96 mm)

The same Titan electronics in a panel-mount frame for LT/HT switchgear fascias.

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Titan Smart Energy Meter

Class 0.5S 3-phase DIN rail meter with built-in WiFi, Ethernet, RS485.

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Titan Audit — Energy Logger

Split-core CT energy logger for zero-downtime audit or retrofit installation.

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kVA to kW Calculator

Convert kVA to kW and Amps to kW — useful when translating nameplate loads to real current draw.

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