Introduction #

Instant answer: connected load is the sum of documented loads connected to a defined system on a consistent kW or kVA basis. Maximum demand is the greatest average load over a stated interval; demand load may instead mean a code-calculated or planning coincident load. A historical meter peak is useful evidence for an existing installation, but it does not by itself replace the applicable feeder/service load calculation, additions, continuous-duty treatment, seasonal representativeness or protection checks.

Open Factory Load — 491 kW demand · PF 0.87 →

Decision gate: which number feeds what #

Use case Use Do not use
Existing transformer/main loading study Representative interval demand plus applicable adjustments and new loads One unqualified monthly peak
New feeder/service planning Applicable calculated load and project duty cases Historical demand from another operating state
Inventory / boom list Connected nameplates Demand as “everything runs”
Utility demand charges Billed demand interval Connected kW
Single motor feeder Branch FLC rules Facility demand factor

When this guide fits: A connected-load inventory is higher than an interval-meter peak and you need to explain which number belongs in inventory, demand analysis, tariff review, and equipment planning.

When it is not suitable: Branch circuit ampacity for a single motor feeder—use NEC branch rules, not facility demand concepts.

Illustrative dataset: The 682 kW inventory and 491 kW peak below demonstrate the calculation path; they are not a real facility record or a substitute for a code-compliant load study.

Connected load higher bar than demand load bar682 kW connected491 kW demand

Definitions — one facility, two numbers #

Term Meaning This plant
Connected load Sum of documented connected input ratings on a consistent basis 682 kW
Illustrative maximum demand Highest average metered real power over the stated 15-minute interval 491 kW
Gap Connected − Demand 191 kW (28%)

Connected load is an inventory quantity, not proof that all loads run simultaneously and not necessarily a hard physical ceiling when records mix motor output ratings, input ratings or missing auxiliaries. Maximum demand describes an observed or calculated coincident condition. Equipment rating and billing decisions use different rules, so keep the term, unit, boundary and interval attached to every number.

Inventory table — where 682 kW came from #

Equipment Qty kW each Connected kW
Form/fill lines 4 85 340
Seal welders 6 8 48
Compressors 2 45 90
Chillers (nameplate) 2 55 110
Lighting + controls — — 52
Offices + misc — — 42
Total connected 682

Demand load is not this table times one magic factor—it is the metered peak below.

Demand proof — where 491 kW came from #

Source Peak kW Window
Illustrative interval-meter peak 491 Defined 15-min average interval
Internal spreadsheet assumption (unsupported) 375 682 × 0.55; no study or code basis

Demand factor: 491 ÷ 682 = 0.720. The inverse, 682 ÷ 491 = 1.389, is not automatically a diversity factor because connected load is not necessarily the sum of individual maximum demands. See the diversity factor guide.

What the illustrative numbers establish #

Quantity Calculation Result
Connected load Nameplate inventory sum 682 kW
Coincident maximum demand Interval-meter example 491 kW
Demand factor 491 ÷ 682 0.720
Apparent demand at PF 0.82 491 ÷ 0.82 599 kVA

The 599 kVA result converts one real-power/PF observation; it is not a final transformer, breaker, conductor or service selection. First establish whether the interval is representative and whether the governing method permits measured demand for this existing installation. Then include added/removed loads and the project-specific continuous duty, growth, temperature, harmonics, starting and protection requirements. Reproduce the conversion in the kW to kVA Calculator and build a simple inventory in the Factory Load Calculator; that tool does not apply jurisdiction-specific demand factors.

Who uses which number #

Decision Use connected Use demand
Existing transformer loading study inventory cross-check representative measured demand + duty cases
New feeder/service calculated load input inventory applicable calculated demand method
Utility demand charge ✓
Branch breaker to one motor ✓ (nameplate × rules)
“How big is my building?” story ✓
Energy kWh estimating schedules/meter boundary interval kW integrated over time, not peak alone

For average vs peak over a billing period, see Load Factor Guide (distinct from diversity above).

Tariff lines: Energy cost optimization.

Worked conversion — demand to main amps #

kW  = 491
PF  = 0.82
kVA = 491 ÷ 0.82 = 599

I = 599,000 ÷ (√3 × 480) ≈ 720 A
This is approximately 720 A for a balanced three-phase 599 kVA interval.

The current conversion does not establish conductor ampacity or breaker rating. Those require the adopted code, load classifications, time behavior, installation conditions and fault/coordination study.

Check feeders with Breaker Size Calculator.

Distribution context: Electrical distribution design. Browse Power calculator hub.

Next steps you should take #

  1. Build the connected inventory table in kW.
  2. Pull utility 15-min peak for the same month.
  3. For an existing installation, test whether the interval history is representative and permitted by the governing method; for new work, perform the applicable calculated-load method.
  4. File both numbers in the project memo—prevent “682 kW” shorthand in bids.
  5. Record the measurement interval, season, shift state, and planned future loads beside the demand value.
Can I add 20% margin to connected load instead of using demand?

Do not apply an unexplained percentage to either number. Establish the governing calculated or measured-load method first, then add only documented future loads, uncertainty or owner reserve without double-counting. See the safety margin guide.

Why is demand lower than connected if everything runs?

Machines rarely hit nameplate simultaneously; some are standby, cycling, or on reduced settings—the **191 kW gap** is normal here.

Does connected load matter for permits?

Yes. Connected load supports the equipment inventory and may be required by permitting or utility processes. Demand is a separate planning input; use the locally applicable load calculation and design criteria for final service and equipment sizing.

What if demand exceeds connected?

Check that the boundary, unit and time basis match; then investigate CT/PT ratios, missing loads, motor output ratings recorded as electrical input, overload operation, on-site generation/import signs, and whether the billing register is kW, kVA or another tariff quantity. Do not assume the meter is wrong merely because the inventory is lower.

How do I explain this to non-engineers?

Connected is the documented equipment inventory added on one basis; maximum demand is the largest average load observed over a stated interval. Billing uses the tariff definition, while equipment sizing uses the applicable calculated/measured-load method—not either number without context.

What is connected load on an electricity bill?

It is tariff- and utility-specific. It may be a declared or assessed sum of connected equipment used for service classification, fixed charges or contract administration; it is not automatically the same as metered kW demand, billed demand or monthly kWh. Read the tariff's definition and unit.

Technical sources #