Compare generator power claims by definition, electrical configuration, duty and source document—not by the largest watt or kVA figure.
Use the rated or running figure for a sustained-load shortlist only after the supplier defines its duty, electrical build, conditions, and output point. Treat peak, maximum, starting, or surge power as a separate short-event claim with its own duration and limits. If those fields are missing, the two numbers are not yet comparable.
Decide which power figure can enter the load plan
Start with the buyer decision, not the largest number on the page. The sustained-load column needs a defined longer-use output. The starting-load review needs a separately defined short-event output and the load event it is expected to support. Neither claim should enter a model ranking until its source and basis are traceable.
Two products may show the same pair of numbers while using different voltage, frequency, units, or rating rules. Record each definition and source before the value enters either column.
The pictured label below is only an example of a visible input. It must still be linked to an exact model, electrical build, duration, and controlled file.
Official pages show why the basis matters. Honda lists one EU2200i as 120 V, 2,200 W maximum, and 1,800 W rated. Yamaha's EF2200iS factsheet lists 230 V, 50 Hz, 2,200 VA maximum, 1,800 VA rated, and power factor 1.0. At the stated power factor, Yamaha's VA and W values are equal. The headline pairs look similar, but the products and markets differ. Neither document defines another maker's use of maximum.
Lock the rating system and electrical build
Portable literature and formal generator-set documents can use different terms. First identify the exact document system, then lock voltage, frequency, phase, unit, and power factor. Portability alone does not decide which standard applies.
| Document context | Labels a buyer may see | What still needs proof |
|---|---|---|
| Product page or manual. | Running, rated, maximum, starting, surge, peak. | Exact meaning, allowed time, protection limit, model, fuel, voltage, frequency, and phase. |
| Quote with a formal duty rating. | COP, PRP, LTP, ESP, or a maker's duty name. | Standard and edition, duty, load profile, site conditions, and maker limits. |
| Alternator or set plate. | kVA, kW, voltage, current, frequency, phase, power factor. | Whether the number is alternator capacity or complete-set output at the required point. |
The ISO 8528-1:2018 scope covers application, ratings, and performance classes for relevant engine-driven AC sets. It has stated exclusions and is not split into “portable” and “industrial” products. Its official page also shows a revision in progress, so any claim should name the edition.
ANSI/PGMA G300-2023 has a narrower field: portable sets up to stated power, voltage, phase, frequency, fuel, and build limits. It excludes other products, including 50 Hz and stationary sets. Within its scope, rated wattage is the maker's output rating. It does not create one global meaning for surge or starting power.
Pass one comparability gate before ranking offers
Keep two numbers out of the same column until the key bases match. A failed row is a request for clarification, not a reason to guess a conversion or discount the offer. This gate is a buyer control, not a claim that one standard requires every row.
| Gate | Pass condition | HOLD condition |
|---|---|---|
| Product. | Exact model, suffix, fuel, and operating mode are clear. | The quote uses only a family name or mixes variants. |
| Electrical build. | Voltage, frequency, and phase match the buyer's need. | A field differs or is missing. |
| Unit. | Both values use kW, or kVA has a stated power factor. | kW and kVA are ranked without a sound conversion. |
| Meaning. | Both suppliers define sustained and short-use values. | One offers only a headline maximum. |
| Duty and time. | Each value has the same use and time basis. | A portable start value is ranked against a formal duty rating. |
| Conditions. | Site, fuel, and test or correction basis are clear. | A corrected value is ranked against an unqualified listing. |
| Output point. | Both refer to the complete set at the same boundary. | Engine, alternator, gross, and net output are mixed. |
| Transient need. | The same load step has clear dip and recovery limits. | A motor-start claim has no project limit. |
| Source. | Quote, data sheet, and revisions can be traced. | Old and current files are mixed. |
Only where the correct basis exists:
kW = kVA × power factor
That formula cannot repair a missing power factor, wrong phase, different duty, or mismatched output point. Site correction must also come from the offered maker and model. There is no safe universal height or temperature discount. Cummins' set-sizing paper, for example, treats duty, fuel, phase, frequency, voltage, altitude, temperature, and allowed dip as separate inputs.
Reconcile the figure across the order file
Not every transaction needs the same five files. Define the required records and their contract priority first. Then reconcile only the fields that should overlap, while keeping each file inside its actual role.
| Record | Capture | Stop when |
|---|---|---|
| Quotation. | Offered build, commercial scope, and power values. | The value has no model or electrical variant. |
| Data sheet. | Unit, power factor, duty, conditions, and revision. | It conflicts with the quote without a signed resolution. |
| Nameplate. | Product identity and required electrical fields. | The plate belongs to another variant. |
| Manual. | Use limits, protection, and connection rules for the set. | Sales wording asks for use the manual does not allow. |
| Test report, when needed. | Sample, build, method, conditions, results, and limits. | The report cannot be tied to the quoted configuration. |
The PGMA standard gives a scoped example: a rating plate and output-test record have different roles. It does not set the buyer's quote format or a universal priority among documents. The broader generator document checklist covers the full order file.
Validate each starting-load event
Starting demand comes from the actual load, the loads already online, and the start order. One multiplier for every motor or appliance cannot establish whether a quoted set will carry the event.
For a simple portable screen, Honda's wattage guide lists different start and run estimates for different loads and warns that real demand may vary. Briggs & Stratton's selection guide uses total running watts plus the largest added start requirement as a consumer screen.
Use that method only with the actual load's plate or manual and the selected generator maker's stated run and start ability. Check the allowed event and protection response. It creates a shortlist, not an industrial approval.
For a B2B or industrial review, record:
- Equipment make and model; voltage, frequency, and phase.
- Running W, kW, VA, or current with the source.
- Start or locked-rotor current where relevant.
- Direct-on-line, soft-start, drive, or other start method.
- Loads already online, start order, and delay.
- Loads that must stay on.
- Power factor and nonlinear traits when material.
- Allowed voltage and frequency dip, recovery level, and time.
First compare the steady loads that run together with the site's sustained rating. Then review each start event while its earlier loads remain online. The supplier return should tie the exact set and controls to the stated event, dip, recovery rule, and source data.
This does not replace a transient study. Cummins' sizing guidance treats motor and load traits, excitation, site, sequence, and allowed dip as material inputs. Its GenSize FAQ says the powered system sets the acceptable dip. If the load or limit is unknown, the decision stays open.
Resolve power conflicts before model approval
Keep both values visible, mark the affected comparison row HOLD, and name the owner of the correction. Release the row only when an authorized record closes the gap. A chat reply with no identity or revision is not enough.
| Conflict | Needed response | Release rule |
|---|---|---|
| Listing is higher than data-sheet rated output. | Map the headline to maximum or start output and state its limit. | The revised quote separates sustained and short-use values. |
| Quote and plate use different units. | Give the power factor and build basis or correct the file. | Values reconcile without a guessed conversion. |
| Manual limit is lower than the sales claim. | Issue the right manual or correct the claim. | The current instruction supports the order. |
| Test uses another model or voltage. | Supply evidence for the offered build. | Sample and tested configuration match the order file. |
| Industrial quote says only “rated power.” | State the duty, standard edition, and load profile. | The technical agreement records the basis. |
No one file controls every field in every deal. Put file priority, signers, test limits, and release authority in the contract. The comparison sheet should retain the old value, source, revision, conflict owner, final record, and acceptance date.
Send a quote-ready power request
Replace “What is the real kW?” with a short split of responsibilities and a required return format.
The buyer supplies the destination voltage, frequency, phase, load list, operating groups, critical loads, start data and order, site conditions, duty, and allowed dip and recovery.
The supplier returns the exact model and options; rated or running output; maximum or starting output; each definition and allowed time; kW, kVA, and power factor; duty and cited standard; electrical build; rated speed where relevant; conditions and site-rated output; output point; auxiliary losses; and the IDs and revisions of the quote, data sheet, plate, manual, and test evidence.
The contract records the accepted build and rating basis, required files, test limits, allowed changes, signers, and hold/release authority. Any field that remains open should carry an owner and due date rather than a guessed value.
Buyers can start with the generator catalogue and send the destination build plus load sheet through the quotation page. A model recommendation should follow the documented load and duty review, not come before it.
