Electrical load assumptions should be checked against the building brief, equipment information and intended operating conditions before a commercial building goes to tender. Start by identifying what is confirmed, what remains provisional and who must resolve each missing input. Then ask the electrical designer to reconcile the calculation with the drawings and specifications issued for pricing.
For Saudi owners and project managers, the useful outcome is a traceable tender basis: bidders can see the included loads, allowances and outstanding decisions. This review does not replace electrical design. It helps the project team ask informed questions before different interpretations become different tender prices.
Begin with the latest approved brief and architectural revision. Record the intended activities, occupied areas, operating hours and expected tenant uses. An office floor, restaurant tenancy and specialist treatment area should not quietly share an unexplained allowance simply because their floor areas are similar.
List the project references used for the calculation, including applicable code editions and supply information. The Saudi Building Code Center identifies SBC 401 as the Saudi Electrical Code and includes building load determination within its objectives. Have the responsible designer confirm the requirements applicable to this project; a code listing alone does not validate a calculation.
Agree which party can authorise changes to occupancy or equipment. Record the date of that decision so the tender team knows whether a later layout change has been incorporated.
Bring the owner, electrical designer and tender coordinator into the review with the same document set. Give each participant a defined task: confirm intended use, explain the technical basis or identify the pricing consequence. This keeps an unresolved design question from being mistaken for an agreed commercial exclusion.
Keep these inputs consistent with the engineering design brief used by the wider project team.
Request a load schedule organised by system and equipment tag. Review HVAC equipment, lighting, socket outlets, lifts, pumps, kitchens, IT systems and specialist installations where they fall within the project. Match equipment tags across mechanical schedules, electrical schedules and layouts rather than comparing totals alone.
For each entry, ask for quantity, electrical input, supply characteristics, source document and revision. Identify whether the figure comes from a selected product, a design estimate or a tenant allowance. A blank field should remain visibly unresolved rather than being treated as zero.
Look for boundaries where work can disappear or be counted twice. Examples include a kitchen priced by a specialist, landlord supplies to tenant panels, external signage and equipment supplied with its own controls. State who includes each load and which package supplies its connection.
Use the checklist below as a sampling guide, then extend it to the project inventory. Start with large or uncertain equipment and scope interfaces. Record the actual schedule entry reviewed so that another team member can repeat the check.
| Load Item | Input Evidence | Review Question |
|---|---|---|
| HVAC assembly | Tagged equipment schedule and supplier data | Electrical input or cooling duty? |
| Lighting and sockets | Layout, use and calculation basis | Quantities and allowances consistent? |
| Pumps and lifts | Supplier rating and operating sequence | Which units can run together? |
| Tenant equipment | Activity and agreed scope boundary | Included, excluded or provisional? |
| Future provision | Defined expansion requirement | Space, spare ways or capacity? |
Check what each equipment rating actually describes. An HVAC cooling duty expresses thermal performance, while the electrical input describes power taken by the equipment. A motor rating may describe mechanical output at the shaft; it should not automatically be entered as electrical input. Schneider Electric’s installation guidance makes this input and output distinction for motors.
Ask the mechanical designer or supplier to identify the relevant electrical data and operating condition. Check whether quoted input covers the complete assembly or only one component. Separate fans, pumps or heaters may require their own entries if they are outside the stated package input.
Keep provisional selections labelled. Record the basis used for tender, the acceptable substitution process and the information needed when equipment is selected. Do not replace missing supplier data with an unexplained percentage.
Power taken by equipment
Use the stated operating condition and package boundary.
Cooling delivered by equipment
This is not an electrical input rating.
Electrical apparent power
Relate to active power using the applicable power factor.
Different quantities may share the letters kW. Check what the rating describes.
Connected load is the total of the electrical loads included on the stated basis. Estimated maximum demand addresses the load expected together under the design conditions. The two figures answer different questions, so a smaller demand total should have an explanation that can be followed through the schedule.
Keep units visible. Kilowatts, or kW, express active power; kilovolt-amperes, or kVA, express apparent power. The power factor relates the two. Ask the designer to show the basis for conversions and aggregation instead of assuming that every equipment item has the same power factor.
A tender summary should identify both the load basis and the scenario represented by its final total. This article supplies no standard power factor or sizing multiplier: those inputs belong to the project calculation.
Ask for an explanation of each utilisation or simultaneity assumption. Utilisation concerns how heavily an individual load operates; simultaneity concerns which loads operate together. Terminology varies between references, particularly around diversity, so require a definition alongside each factor.
Trace a sample load from equipment to the distribution board and then to the main supply summary. Has the same reduction been applied more than once? A downstream figure that already includes an operating assumption should not receive another unexplained reduction upstream.
Request the applicable calculation reference and the reason it fits the occupancy and load group. Manufacturer guidance explains the principles but does not establish one universal factor for Saudi commercial buildings. Where the basis is uncertain, record a designer clarification rather than selecting a convenient number to reach a preferred capacity.
Ask for separately identified normal and standby operating cases, with essential or emergency loads defined by the project strategy and applicable requirements. The reviewer should be able to see which equipment remains in service and which equipment is excluded in each case.
Check equipment described as duty and standby. Establish whether the control sequence prevents simultaneous operation, permits overlap during changeover or calls for both units under certain conditions. Labels alone are insufficient evidence for removing a load.
Keep steady running demand separate from starting and transfer considerations. Ask the electrical designer to confirm how these matters are assessed. Do not interpret a running-load total as proof that a generator or other source is suitable.
For unlet commercial space, state the assumed tenant activity, area basis, included services and exclusions. Identify who must revisit the allowance if a future tenant proposes a restaurant, intensive IT use or other materially different equipment. Make the tender documents clear about what the base building provides.
Describe future provision precisely. Spare circuit ways are unused connection positions; spare physical space concerns room or enclosure expansion; spare electrical capacity concerns the ability of the relevant system to serve additional demand. These are separate review questions.
Ask which future loads are included in the present calculation and which are only possibilities. A general note saying “allow for expansion” does not tell bidders whether to price equipment capacity, containment, room space or future works.
For example, a future floor fit-out might require a reserved route without any equipment being purchased now. Alternatively, the owner may require usable capacity from day one. Ask for a separate description of each provision and where it appears in the tender scope; avoid bundling both into a single contingency note.
Identify the available written supply information and its status. Distinguish a proposed connection arrangement from confirmed project information. Ask the designer to state any unresolved constraints and explain whether they affect the tender basis. Avoid implying that an estimated building demand establishes available utility capacity.
Compare the final schedule with the single-line diagram, equipment schedules, specifications and bill of quantities. Use revision references so the cost team can check that the same design basis is being priced. Resolve contradictory totals or issue a clear clarification to all bidders through the agreed tender process.
Record exclusions and alternative proposals explicitly. If a bidder proposes different equipment, request its electrical data and the designer’s assessment of the consequences before comparing the price as an equivalent offer.
Coordinate mechanical equipment inputs through the project’s MEP design scope so the schedules use consistent information.
Consider an illustrative commercial office tender. The mechanical schedule lists an air-handling unit’s cooling duty, but its electrical input field is blank. The electrical schedule contains a provisional fan input with no supplier reference. The review finding is missing evidence; it is not permission to substitute the cooling figure.
The mechanical designer identifies the selected fan arrangement and obtains electrical information for the proposed assembly. The electrical designer checks what is included, updates the tagged entry and reviews the affected calculations. The tender coordinator then aligns the schedule, drawings and priced scope to the same revision.
If selection remains open, retain a clearly stated provisional basis and identify the information and decision needed to close it. The clarification register below shows how to keep that uncertainty visible. This is an instructional example, not a Crown Axis project case study or an equipment-sizing recommendation.
Closure evidence should identify the equipment tag, supplier document revision and revised electrical schedule. A reply saying “load checked” is difficult to audit if the underlying entry cannot be found. Record any remaining exclusion, such as a separately supplied heater, so it is picked up in the correct package.
| Open Item | Responsible Party | Evidence to Close |
|---|---|---|
| AHU input unverified | Mechanical designer / supplier | Tagged electrical input and inclusions |
| Calculation update | Electrical designer | Revised load entry and affected checks |
| Tenant activity unknown | Owner / leasing team | Agreed use and allowance boundary |
| Tender revisions differ | Tender coordinator | Aligned document issue references |
Before issue, ask the team to close each material input or explain how it is carried into the tender. Every open item needs a responsible party, required evidence, target date and affected document reference. Keep technical acceptance with the appointed designer and commercial treatment with the responsible tender team.
Retain the agreed schedule and clarification record with the tender issue. When an assumption changes, identify the affected revision and communicate the change consistently. A useful final review leaves a documented basis for electrical load assumptions.
Crown Axis provides electrical services, including power distribution and lighting design. Share your commercial building brief, equipment schedules and tender information to discuss the required review scope. Contact Crown Axis to clarify the engineering inputs needed for your project.
It can be planned around provisional inputs where the project team agrees on a clear basis and commercial treatment. Identify the affected equipment, source of the estimate, exclusions and confirmation date. The responsible designer should assess whether the remaining uncertainty is acceptable for the intended tender issue. Do not present provisional equipment information as a final selection.
Existing consumption records can inform discussion about an existing building, but they describe the operation recorded during that period. They do not automatically represent a changed occupancy, extended building or new equipment package. Ask the designer what the available records demonstrate, what conditions differ and what further information is needed for the proposed works.
The owner or leasing team should define the intended tenancy assumptions, while the electrical designer assesses their technical treatment. Record both responsibilities and obtain specialist input where the expected use requires it. If the tenant activity remains unknown, state the limits of the allowance and the process for reassessing a later tenant proposal.
No. A checklist helps organise questions, evidence and responsibilities; it is not a compliance certificate or a substitute for design calculations. The appointed electrical professional must assess the applicable Saudi requirements and project conditions. Any authority or supply-provider requirements also need to be addressed through the relevant project process before claiming the necessary acceptance.
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