Seven client-side calculators for early-stage sizing and budgetary planning — cable sizing, transformer & BESS sizing, solar strings, fault current, power factor correction, and unit conversion. Standard formulas, your inputs, nothing sent to a server.
These tools are built for the budgetary and early-design stage of a project — sizing a feeder, roughing in a transformer or BESS order, or checking a string configuration before it goes to a stamped design. They run entirely in your browser: nothing you enter is sent anywhere. None of them replace a licensed engineer's calculation for final design, protective device coordination, or code compliance sign-off.
Estimates voltage drop across a feeder using the standard K-factor method, then flags runs that exceed the commonly used 3% branch-circuit / 5% total design guideline (NEC 210.19(A) informational note — a recommendation, not a hard limit).
Converts a real load in kW to required kVA and rounds up to the nearest standard ANSI/IEEE C57.12.00 transformer nameplate rating, plus estimated full-load amps on the secondary.
Converts a critical load and backup duration into usable energy, then to the nameplate energy rating you'd need to procure once depth of discharge and round-trip efficiency losses are factored in. See Battery Storage for DC block configurations.
Applies module temperature coefficients to your site's design temperatures to find the maximum string length (cold-weather Voc must stay under the inverter's max input voltage) and minimum string length (hot-weather Vmp must stay in the inverter's MPPT window).
A simplified, infinite-source estimate of available symmetrical fault current at a transformer's secondary terminals — useful for a first-pass equipment rating check, not a substitute for a full short-circuit/coordination study that accounts for source and cable impedance.
Sizes the capacitor bank (kVAR) needed to raise real power at an existing power factor up to a target power factor.
Quick conversions between kVA, kW, and power factor, AWG wire gauge and mm², and an approximate NEMA-to-IP enclosure rating cross-reference.
| NEMA type | Approx. IP equivalent | Typical use |
|---|---|---|
| 1 | IP20 | Indoor, general purpose |
| 2 | IP21 | Indoor, light dripping water |
| 3 | IP54 | Outdoor, windblown dust/rain |
| 3R | IP14 | Outdoor, rain/sleet (vented) |
| 4 | IP56 | Outdoor, hosedown/splashing water |
| 4X | IP66 | Outdoor, corrosion-resistant + hosedown |
| 6 | IP67 | Occasional temporary submersion |
| 6P | IP67 | Prolonged submersion + corrosion-resistant |
| 12 | IP52 | Indoor, dust/dripping non-corrosive liquids |
A transformer loses energy as heat continuously: a fixed no-load loss (core loss, present anytime it's energized, loaded or not) and a load loss (winding loss that scales with the square of the load factor). Over a 20–30 year service life, that loss can cost more than the transformer itself — so total cost of ownership, not sticker price, is often the better basis for comparing bids of the same kVA size. Enter both loss figures from the nameplate or factory test report.
MACRS (Modified Accelerated Cost Recovery System) lets US businesses depreciate equipment faster than its useful life, using the IRS's published 200%-declining-balance, half-year-convention percentage tables (Publication 946, Table A-1). Most energy equipment falls under 5-year or 7-year property.
A quick-reference pairing of common US standards (ANSI/IEEE/NEMA/UL) with their closest international (IEC) counterpart for the same equipment category. These are commonly paired equivalents for similar equipment classes, not certified legal equivalencies — a UL listing and an IEC/CE certification are separate compliance processes with their own testing requirements.
| Equipment category | US standard | International (IEC) standard |
|---|---|---|
| Power transformers | IEEE/ANSI C57.12.00 | IEC 60076 |
| Medium-voltage switchgear | IEEE C37 series | IEC 62271 series |
| Low-voltage circuit breakers | UL 489 | IEC 60947-2 |
| AC motors | NEMA MG-1 | IEC 60034 |
| Enclosure ratings | NEMA 250 | IEC 60529 (IP code) |
| Wire/cable sizing | AWG / NEC Chapter 9 | IEC 60228 (mm²) |
| Battery energy storage safety | UL 9540 / UL 9540A | IEC 62619 / IEC 63056 |
| Grounding / earthing | IEEE 80 | IEC 61936-1 |
| Surge protective devices | UL 1449 | IEC 61643 |
Copper/aluminum pricing and interconnection queue congestion both move fast enough that a static number on this page would be stale within days — so rather than publish figures we can't keep current, here are the real sources procurement and interconnection teams actually track:
Sticker price and delivered cost are rarely the same number once freight, duty, and insurance are added — this rolls them into one figure for budgeting.
The Harmonized System (HS) is the WCO's internationally standardized product classification, used as the basis for every country's customs tariff schedule. The 4-digit headings below are stable across countries; the more specific 6–10-digit subheading that actually sets your duty rate depends on technical details (voltage class, power rating, technology) and the importing country's own tariff schedule — always confirm final classification with a licensed customs broker.
| Equipment category | HS heading | Description |
|---|---|---|
| Transformers | 8504 | Electrical transformers, static converters, and inductors |
| Switchgear >1000V | 8535 | Electrical apparatus for switching/protecting circuits, voltage >1000V |
| Switchgear/breakers ≤1000V | 8536 | Electrical apparatus for switching/protecting circuits, voltage ≤1000V |
| Panels & switchboards | 8537 | Boards, panels, and consoles for electric control or distribution |
| Generating sets | 8502 | Electric generating sets and rotary converters |
| Motors | 8501 | Electric motors and generators (other than generating sets) |
| Batteries / accumulators | 8507 | Electric accumulators, including separators |
| Solar cells / modules | 8541 | Semiconductor and photosensitive devices, including photovoltaic cells |
| Insulated wire & cable | 8544 | Insulated wire, cable, and other insulated electric conductors |
Buyers often treat these marks as interchangeable — they aren't. Some are independent third-party certifications; one is a manufacturer's own self-declaration.
| Mark | Issued by | What it actually means |
|---|---|---|
| UL Listed | UL (Underwriters Laboratories) | Third-party safety testing and certification to a US standard — the most common NRTL mark in North America. |
| ETL Listed | Intertek | An equivalent third-party NRTL certification to UL, testing against the same underlying US safety standards. |
| cULus | UL | Certifies compliance with both US and Canadian safety standards in a single mark. |
| CSA (or cCSAus) | CSA Group | Canadian safety certification; the cCSAus variant covers both Canada and the US. |
| CE Marking | Manufacturer (self-declared) | The manufacturer's own declaration of conformity to applicable EU directives, required for sale in the European Economic Area — not a third-party lab certification like UL. |
| RoHS | EU directive compliance | Restricts specific hazardous substances (lead, mercury, cadmium, and others) in electrical and electronic equipment. |
| FCC | US Federal Communications Commission | Certifies electromagnetic interference / radio-frequency emissions compliance for equipment containing electronics. |
How long a generator will actually run on a full tank at a given load — use the fuel consumption rate from the genset's own spec sheet at your expected load point (most spec sheets publish gal/hr at 50%, 75%, and 100% load).
Once you've got a size in hand, configure the actual part: transformers and switchgear for the data-center desk, BESS DC blocks and PCS for storage, or inverters and BOS for solar. Building a full BOM instead of one part? Quick Order matches every line to the catalog in one pass, and the Lead-Time Index shows current lead times across major equipment categories before you commit to a design.
Using the K-factor method: VD = (2 × K × I × D) / CM for single-phase or VD = (1.732 × K × I × D) / CM for three-phase, where K is a resistivity constant (about 12.9 for copper, 21.2 for aluminum), I is load current in amps, D is one-way distance in feet, and CM is the conductor's circular mil area. This is an approximation that ignores reactance and is best suited to feeders under about 250 feet.
Divide your real load in kW by its power factor to get required kVA, then round up to the nearest standard transformer nameplate rating (common ANSI/IEEE sizes include 75, 112.5, 150, 225, 300, 500, 750, and 1000 kVA). Always leave margin for future load growth.
Multiply the critical load in kW by the required backup duration in hours to get usable energy in kWh, then divide by your assumed depth of discharge and round-trip efficiency (commonly around 90% each for LFP systems) to get the nameplate energy rating you need to procure.
No. These tools use standard simplified formulas for early-stage budgetary sizing and procurement planning. Final designs, especially fault current and arc-flash coordination, require a licensed engineer's study using actual system impedances.
Add the purchase price to the lifetime cost of its energy losses. No-load loss (core loss) runs continuously whenever the transformer is energized; load loss (winding loss) scales with the square of the load factor. Multiply each by 8760 hours/year and your electricity rate to get an annual loss cost, then extend it over the transformer's service life.
MACRS (Modified Accelerated Cost Recovery System) lets businesses depreciate equipment faster than its useful life using IRS-published percentage tables (5-year and 7-year property are common for energy equipment). This is a simplified estimate only — it doesn't account for bonus depreciation or Section 179 expensing, and isn't tax advice.
Add the equipment price, freight, duty (equipment price multiplied by the applicable duty rate), and cargo insurance together. The duty rate depends on the item's actual customs classification, which should come from a licensed customs broker, not an estimate.
Divide the fuel tank capacity (gallons) by the fuel consumption rate at your expected load (gallons per hour), taken from the generator's own spec sheet — most gensets publish consumption rates at 50%, 75%, and 100% load.
Search a wide range of configurable SKUs across transformers, switchgear, inverters, storage, and MRO.