Load planning workflow

Electrical Load Schedule: Connected Load vs Demand Load

Load-planning guide · Reviewed 22 Sep 2026 · ElectroDesigner

Connected load and demand load answer different questions. Connected load is the arithmetic sum of installed ratings. Demand load is the estimated maximum load expected to operate at the same time under a stated operating model. A useful load schedule preserves both values so the engineer can see exactly where simultaneity, utilization and power-factor assumptions enter the design.

In this article1. Connected vs demand load 2. Core equations 3. Worked example 4. Practical workflow 5. Assumptions and limits

1. Connected load and demand load

Connected load is the sum of the nameplate or adopted design ratings connected to the installation. It is useful for inventory and scope, but it usually does not represent the simultaneous maximum demand of a real installation.

P_connected = Σ(n_i × P_i)

Demand load applies a justified demand factor to each load or load group. The factor should come from the applicable code, utility rule, client standard, measured operating profile or documented engineering assumption — not from a generic value copied without context.

P_demand = Σ(n_i × P_i × DF_i)

Do not hide the assumption: if a 0.70 demand factor changes a 100 kW connected group into 70 kW of design demand, the schedule should show the 0.70 explicitly and record its basis.

2. From row demand to kVA and current

Where load groups have different power factors, calculate apparent power row by row rather than collapsing the entire schedule into one assumed power factor:

S_demand = Σ[(n_i × P_i × DF_i) / PF_i]

For a balanced three-phase system:

I = S × 1000 / (√3 × U_LL)

For single-phase AC:

I = S × 1000 / U

This is a planning model. Nonlinear loads, harmonic current, phase imbalance, motor starting and time-dependent sequencing can require a more detailed study.

3. Worked example: connected load is not maximum demand

Consider a 400 V three-phase installation with three load groups:

Group	Connected kW	PF	Demand factor	Demand kW	Demand kVA
HVAC	4 × 15 = 60	0.88	0.75	45.0	51.14
Pumps	3 × 11 = 33	0.90	0.80	26.4	29.33
Lighting	20	0.95	1.00	20.0	21.05

P_connected = 60 + 33 + 20 = 113 kW

P_demand = 45 + 26.4 + 20 = 91.4 kW

S_demand = 51.14 + 29.33 + 21.05 = 101.52 kVA

I = 101.52 × 1000 / (√3 × 400) = 146.53 A

The schedule therefore reports both the 113 kW installed scope and the 91.4 kW / 101.52 kVA planning demand. The ratio 91.4 / 113 = 0.809 is a useful summary of this specific schedule, but it does not replace the documented row assumptions.

Run the Electrical Load Schedule Calculator

4. Practical load-schedule workflow

List every load group with a clear description and quantity.
Record the adopted active-power rating and power factor for each row.
Apply a demand factor only when its basis is defensible and documented.
Calculate connected kW, demand kW and demand kVA separately.
Convert the coincident apparent power into system current using the actual voltage and phase arrangement.
Separate normal, standby, essential and future loads where the operating cases differ.
Run scenario cases where starting, seasonal duty or load management can create a different peak than the static schedule.
Carry the governing demand case into feeder, transformer and generator studies without silently changing assumptions.

5. Assumptions and limits

Demand factors are not universal constants. Values can depend on jurisdiction, building type, utility rules, client criteria and measured operation.
Do not apply a demand factor and a diversity/coincidence allowance to the same effect twice.
Static load schedules do not prove motor-starting performance, voltage dip, generator transient response or harmonic loading.
Future-load allowances should be visible as separate design assumptions rather than hidden inside arbitrary factors.
For loads subject to specific code requirements or active load-management rules, use the applicable rule rather than a generic factor.

Adjacent checks

Read Demand Factor vs Diversity Factor before mixing group assumptions. Use the Three-Phase Power Calculator to verify kW/kVA/current relationships and the Generator Sizing Calculator when the governing load case must be carried into source sizing.

Engineering references

Public methodology references: Schneider Electric Electrical Installation Guide — Power loading of an installation, Estimation of actual maximum kVA demand, and example application of utilization and simultaneity factors. Practical factor values can come from local standards or guides rather than a single universal international table.