Energy monitoring guide
Sub-metering: know where every unit goes.
The DISCOM meter tells you what the whole plant used. Sub-meters tell you which department, line or machine used it. That is the difference between knowing the bill went up and knowing why.
What sub-metering is
Sub-metering means a meter on each important panel, feeder or machine downstream of the main incomer. Each one measures its own share of the load, so energy, Maximum Demand contribution and power factor can be seen department by department.
What to meter first
- The main incomer, to match the DISCOM bill.
- The largest loads: compressors, furnaces, chillers, moulding and extrusion lines. A few loads usually make up most of the bill.
- Loads that run at night or between shifts: utilities, lighting, HVAC. That is where idle energy hides.
- Each department or building, if costs are shared or charged to separate units.
- Solar and DG outputs, so every source is counted. See solar, DG and grid.
A panel hierarchy that adds up
Meters sit in a tree: the incomer, the main panels under it, the feeders under those. Linking each meter to its parent does two things. Every unit is counted once, so a feeder is never added on top of the panel that already includes it. And the gap between a parent and the sum of its children shows up as unmetered load, often the first clue to something nobody knew was running.
Why the totals don’t match
- Loads with no meter of their own: the unmetered remainder.
- Cable and transformer losses between the incomer and the feeders.
- A meter with the wrong CT ratio set, or a CT fitted the wrong way round.
- Different reading times between meters.
Energy per unit made
Enter daily production against a meter and you get specific energy consumption: units of electricity per tonne, piece or batch. That number stays meaningful when production rises or falls, which the monthly bill does not.
Sub-metering in KONDUKTOR® EMS
- Up to 10 meters per gateway, with more gateways for larger plants and more than one plant in one dashboard.
- A panel hierarchy with each meter linked to its parent, unmetered load shown, and every unit counted once.
- Daily production entry and specific energy consumption.
- Meters compared side by side, and every meter’s history exported to Excel.
Common questions
What is sub-metering in a factory?+
Fitting meters on individual panels, feeders or machines below the main incomer, so the energy, demand and power factor of each department or line can be seen separately instead of only as a plant total.
How many sub-meters does a plant need?+
Fewer than most expect. Start with the incomer and the few largest loads, which usually make up most of the bill, then add meters where the unmetered remainder is large or where costs need to be split.
Why don’t our sub-meter totals match the main meter?+
Usually because of loads with no meter, cable and transformer losses, or a sub-meter with the wrong CT ratio or a reversed CT. A panel hierarchy shows the unmetered remainder for each panel, which narrows down where to look.
See where every unit goes, panel by panel.
Book a live demo and see a panel hierarchy on meters like yours.