Optional Method Dwelling Load Calculator

A dwelling load worksheet organizes connected electrical loads and applies an entered demand factor to each load row. The resulting estimated demand load provides a documented VA figure for preliminary dwelling load review, including early service, feeder, panel, and load-schedule planning.

The worksheet produces three electrical values:

• Connected load — the total VA entered across all load rows.
• Estimated demand load — the total VA remaining after each row’s entered demand factor is applied.
• Diversity allowance — the VA difference between connected load and estimated demand load.

For a dwelling electrical load calculation, connected load represents the full nameplate or assigned load value entered into the worksheet. Demand load reflects the portion expected after the selected demand factors are applied. That demand figure may be carried into a larger service or feeder calculation only after the applicable dwelling calculation method, load classifications, and code requirements have been independently verified.

Load Rows and Demand Factors

Each Load row identifies a load category and its calculation treatment. The worksheet uses the following fields for every row:

Field	Electrical use
Load label	Identifies the entered load category, such as general load or appliance load.
Connected load (VA)	The full apparent-power value assigned to that load row before diversity or demand is applied.
Demand factor (%)	The percentage of the connected load included in the estimated demand load.
Method reference	Records the reviewed dwelling method or table reference used to support the selected treatment.
Source reference	Records the underlying source for the entered load values and demand factors.

Use Connected load (VA) consistently. Apparent power in volt-amperes is commonly used during service and feeder load review because it can be converted to calculated current at the applicable system voltage:

\(\displaystyle I = \frac{VA}{V}\)

For example, a 9,000 VA calculated load at 240 V corresponds to 37.5 A before any separate decisions involving conductor ampacity, terminal rating, overcurrent protection, continuous-load treatment, or other installation requirements.

A demand factor is entered as a percentage, not as a decimal. A value of 75 means that 75% of the row’s connected load is included in the estimated demand load.

Dwelling Load Arithmetic

The worksheet preserves row-level arithmetic rather than assigning a dwelling method automatically. Its formulas are:

\(\displaystyle \text{Connected load} = \sum \text{entered connected load rows}\)

\(\displaystyle \text{Estimated demand load} = \sum \left(\text{connected load} \times \frac{\text{row demand factor}}{100}\right)\)

\(\displaystyle \text{Diversity allowance} = \text{connected load} - \text{estimated demand load}\)

The diversity allowance is not an additional load or a conductor-sizing result. It is the amount of connected VA removed by the entered demand factors. It helps show how much of the original connected load is being excluded from the estimated demand figure.

Calculation Example

Assume the worksheet contains two load rows.

Load label	Connected load (VA)	Demand factor (%)	Demand load contribution
General load	3,000 VA	100%	3,000 VA
Appliance load	8,000 VA	75%	6,000 VA

The worksheet result is:

\(\displaystyle \text{Connected load} = 3{,}000 + 8{,}000 = 11{,}000 VA\)

\(\displaystyle \text{Estimated demand load} = (3{,}000 \times 1.00) + (8{,}000 \times 0.75) = 3{,}000 + 6{,}000 = 9{,}000 VA\)

\(\displaystyle \text{Diversity allowance} = 11{,}000 – 9{,}000 = 2{,}000 VA\)

The 9,000 VA estimated demand load is the worksheet’s calculated output. At a nominal 240 V supply, that value is equivalent to:

\(\displaystyle \frac{9{,}000 VA}{240 V} = 37.5 A\)

That current conversion can support preliminary comparison with service equipment, feeder conductors, or panel capacity. It does not, by itself, establish an allowable ampacity or a final conductor size in AWG or kcmil.

Record References

The Method reference and Source reference fields maintain the basis for the calculation record.

A Method reference can identify the selected dwelling calculation approach, table, or reviewed calculation record. A Source reference can identify the load schedule, equipment data, plan set, appliance listing, or other source used to establish the entered loads. When both references are present, the worksheet reports Record comparison: Source recorded.

These references are particularly useful when the demand load is later reviewed against panel schedules, service calculations, permit documents, design revisions, or AHJ comments. They make it possible to trace each entered factor and connected-load value without embedding a code decision into the arithmetic itself.

Service and Feeder Limits

This worksheet performs entered-value arithmetic only. It does not select an optional dwelling method, determine required service or feeder ampacity, size conductors, select an overcurrent protective device, determine raceway fill, calculate voltage drop, or establish a final dwelling load result.

Verify separately:

• Whether the selected dwelling load method and demand factors apply to the installation.
• Whether each entered Load label is classified and valued correctly.
• Required treatment of fixed appliances, HVAC equipment, ranges, dryers, motors, continuous loads, and noncoincident loads.
• Available conductor ampacity after considering terminal rating, insulation temperature rating, correction factor, adjustment factor, and current-carrying conductors.
• Service equipment ratings, feeder ratings, branch-circuit requirements, voltage drop design criteria, and local AHJ requirements.

The worksheet provides a traceable connected-load total and estimated demand-load total from the values entered. Final electrical design and code compliance remain dependent on the verified installation conditions and the applicable requirements.