Guides
UPS Proposals: Compare Protected Loads, Capacity and Runtime
Define the equipment a UPS must support, calculate a transparent load example, and compare proposal capacity and runtime on the same basis.
DETIAN ICT · Tanzania & East Africa
Discuss your ICT project with DETIAN.
DETIAN ICT supports audiovisual, security, network and smart-building projects in Tanzania and East Africa, with design, equipment supply, installation and maintenance services.
Share your site location, required systems and available drawings or equipment list. Start a discussion about the work scope and the information still needed.
Decide what must keep working and for how long
Before requesting a UPS quotation, name the work that must continue during a power interruption, list every local device that work depends on, and agree the required duration. Then compare two separate answers: can the proposed UPS support the electrical load, and can its specified battery arrangement support that load for the required time? A capacity label alone does not answer both.
For an office or project compound, the requirement might be to keep a local application available while staff finish an agreed task, or to give an administrator time to complete an orderly shutdown. State which outcome is wanted. “Keep the rack on” leaves the protected equipment, users and duration unclear.
DETIAN lists UPS systems within its Networks & Data Rooms solutions and asks that network planning consider power alongside equipment and cabling. This guide develops a procurement comparison for that scope. It does not prescribe electrical installation, battery work or a procedure for interrupting a live system.
Draw the boundary around the protected task
Trace one task from the user device to the equipment it needs. A local file task may depend on a workstation, a network switch and a server. An online task may also depend on a router, provider equipment and services outside the site. Record those dependencies instead of assuming that powering one box preserves the complete service.
For each device, mark its intended treatment: included on this UPS, supplied through another confirmed arrangement, intentionally excluded, or unresolved. Explain the effect of an exclusion. Keeping a server powered does not help someone whose required workstation or network path is unavailable.
A site UPS cannot establish that an upstream internet provider will remain available. Ask the service owner to identify such external dependencies and any acceptable alternative workflow. Keep this requirement about a defined local arrangement; do not turn it into a promise of uninterrupted internet or application availability.
If the task is shutdown, ask the application and IT owners to establish the sequence, initiating method and time needed. Include any software, permissions, communications and unattended-operation requirements in the supplier questions. A battery duration does not, by itself, provide an automatic shutdown function.
Build a load record with a clear evidence basis
Use one row per equipment group and operating state. Include: equipment ID; quantity; model; protected task; watts per unit; volt-amperes per unit; document or measurement reference; operating condition; included or excluded status; proposed UPS group; and unresolved owner. Keep opening requirements and planned additions in separate rows.
Schneider Electric explains that watts and volt-amperes are different ratings and that neither UPS limit may be exceeded. Ask for both figures for the proposed UPS and a supported basis for both load totals. If only one load figure is known, leave the other unresolved until the technical reviewer supplies the missing evidence; do not silently treat watts as VA.
Describe whether a value is a manufacturer limit, a design allowance or a reading under named conditions. A single idle reading is not evidence of the required load during every intended activity. Ask the technical reviewer to account for relevant peaks and starting behaviour when establishing the design figures.
For a PoE switch, distinguish downstream port allocations from the complete switch input load presented to the UPS. If a supported input figure already includes the switch and its powered devices, do not add those same devices again. Conversely, a downstream PoE total alone omits the question of the switch’s own input requirements. Have the designer resolve the accounting boundary.
Calculate an opening load and a specific expansion
The following is an invented worksheet example. Every equipment load, duration and offer below is fictional, not a typical device rating, DETIAN quotation or measured installation. Assume the technical reviewer has supplied the stated W and VA values for the same defined operating state and that each row appears once.
L1 — One gateway: 24 W and 30 VA. L2 — One PoE switch, including its agreed powered devices at its input boundary: 180 W and 225 VA. L3 — One small server: 160 W and 200 VA. The opening total is 24 + 180 + 160 = 364 W, and 30 + 225 + 200 = 455 VA.
L4 — One planned additional device: 60 W and 75 VA. The expansion total becomes 364 + 60 = 424 W and 455 + 75 = 530 VA. Keep the addition visible so a supplier can state whether its proposal covers opening day only or the expanded scope.
The fictional owner requires all four rows to remain supported for 20 minutes at that defined expanded load. User laptops are outside this UPS scope and their required independent power arrangement remains a separate project dependency. These assumptions define the example; neither 20 minutes nor any reserve percentage is a general recommendation.
If the project wants an additional engineering allowance, state its basis and ask the designer to show its effect on capacity and runtime requirements. Do not hide an unspecified allowance inside L4, and do not count a future device twice as both an addition and an extra load allowance.
Compare three offers against the same requirement
Use three columns of questions for every offer: W and VA capacity; runtime evidence for the agreed load and battery configuration; and remaining site or operating dependencies. This prevents a large VA number or a long duration at a lighter load from becoming an automatic purchase decision.
Fictional Offer A states 600 W and 1,000 VA capacity, with “20 minutes at 200 W”. The example expanded load is below both capacity limits: 600 − 424 = 176 W and 1,000 − 530 = 470 VA remain before any further design allowance. But 200 W is not the requested 424 W. Mark capacity arithmetic as within the stated limits and runtime at the required load as unresolved.
Fictional Offer B also states 600 W and 1,000 VA. Its supplier evidence identifies the exact proposed UPS and battery pack and states 22 minutes at 424 W under specified battery and environmental conditions. That describes a two-minute difference from the example’s 20-minute requirement. It is the closer documentary match, subject to reviewing those conditions, the VA requirement and the actual project design; it is not a measured result or final acceptance.
Fictional Offer C states 400 W and 800 VA, with “40 minutes at 350 W”. The required 424 W exceeds its stated watt capacity by 24 W even though 530 VA is below 800 VA. The attractive duration does not cure that capacity mismatch. Ask for a revised proposal or an explicitly reviewed change to the protected scope.
The next action is now specific: ask A for runtime evidence at the required load, review B’s complete configuration and assumptions, and return C’s watt-capacity exception. Comparing prices can follow on the same agreed scope. None of these fictional offers identifies a real product, brand availability or price.
Require runtime evidence for the offered configuration
Eaton’s sizing guide treats capacity and runtime as separate questions and relates runtime to load and the battery arrangement. Request the manufacturer’s runtime curve, table or supported sizing output for the exact proposed model and battery configuration. Keep its document date, load point and conditions beside the quotation.
Ask the supplier how the evidence applies to the required operating state, expected battery condition and site environment, and how any agreed allowance is handled. A duration for an unspecified battery pack or a different load leaves a comparison gap. Do not infer minutes by dividing a VA label by a watt total.
If the owner intends to stop some equipment early and keep other equipment running longer, record those stages explicitly and request an assessment of that load profile. The constant 424 W example does not model staged shutdown. Do not add or subtract minutes from a constant-load runtime claim to manufacture a new result.
Record who will maintain the battery and review the load record when equipment changes. Ask about the applicable maintenance, replacement and support arrangements for the actual proposal. An opening-day document does not establish future battery condition or an unlimited support entitlement.
Keep installation and acceptance questions attached
Have the responsible electrical and ICT specialists assess the proposed supply, connections, location, ventilation, physical support and compatibility with any existing backup arrangement. Use the rack-location record for the site observations. A load worksheet cannot establish that the building or cabinet is ready for the selected equipment.
Before ordering, agree how the supplier will demonstrate the protected task and the relevant capacity, runtime and shutdown requirements, including participants, conditions and records. Any interruption exercise needs an authorised procedure for that site. Do not pull plugs, open equipment or alter battery connections to fill this worksheet.
Keep manufacturer estimates, supplier commitments and observed results distinguishable. A later result should identify the installed model and batteries, actual load basis, test conditions, task outcome and exceptions. If a runtime or shutdown check has not been performed, record it as untested instead of describing the entire arrangement as accepted.
Send DETIAN a bounded UPS project enquiry
Prepare the country and town, facility type, protected business tasks, opening and expansion load rows, duration requirements, existing equipment and available site information. Include unresolved input ratings, external dependencies and any restrictions on operational interruptions. This gives the project discussion a defined load and an outcome to assess.
Use DETIAN’s official contact page, email [email protected] or call +255 723 666 959 to discuss design, supply, installation and support scope. Ask which assessment and verification work can be included. Equipment availability, battery configuration, site attendance, costs and delivery arrangements require confirmation for the actual enquiry.
