Protection Calculators: Cable, Voltage Drop & Breaker Planning
Start an electrical feeder check with breaker size, cable size, and voltage drop. Use the breaker size calculator when load amps are known.
This hub is the primary entry for the Electrical cluster: convert kW and kVA, estimate line current, size breakers and conductors, and validate voltage drop before detailed coordination studies. For facility load roll-up and transformer or generator sizing, continue to the Power Calculator hub.
What is an Electrical Calculator?
An electrical calculator helps engineers move from power values to current, protection ratings, and conductor sizes with structured assumptions. It supports retrofit checks, new panel planning, and feeder validation where quick but traceable screening improves decision quality before compliance studies.
Common Electrical Calculations
Convert kW to kVA and kVAR using realistic power factor.
Convert kVA to amps for single- and three-phase systems.
Calculate 3-phase kW and kVA from voltage, current, and PF.
Size breakers and cables from estimated load current.
Check voltage drop on feeders before final conductor selection.
Start Here
Pick the path that matches your question. Most protection workflows start from current; conversion workflows start from kW or kVA.
Have kW or kVA?
Start with kW ↔ kVA conversion, then kVA to amps for feeder current.
For the Electrical cluster, three-phase power formulas (√3, kW, kVA, amps) are the central knowledge entity—conversion, breaker, and cable tools on this hub assume the same V–I–PF relationships. Start with the authority guide, then use topic tools below.
3 Phase Power Calculation Examples
Worked √3 examples for kW, kVA, and line current—the canonical three-phase formula reference for feeder and protection screening on CalcPanel.
Facility PF correction, capacitor bank guides, and kVAR screening live on the Power Calculator hub. This Electrical hub handles conversion, breaker, and cable checks after kVA and amps are known.
Dedicated breaker sizing calculator—OCPD frame screen from load amps or kW with continuous/motor margin. Use this tool instead of duplicating breaker math on the hub.
Scenario guides for multi-step branch-circuit planning—roll continuous load, pick breaker frame, then size conductors. Calculator tools remain on this hub; open a card when you are buying or screening a specific install type.
Homeowners and electricians screen a dedicated 240 V Level 2 EV charger circuit before buying wall units or receptacle kits. Plan continuous amps from the EVSE setting, apply a 125% continuous factor for breaker frame selection, then size copper or aluminum feeder ampacity and check voltage drop on long garage runs. Common screens land at 40 A for 32 A continuous, 50 A for 40 A continuous, and 60 A for 48 A continuous at 240 V. Confirm dwelling load spare capacity, GFCI or listed EVSE protection, and OEM disconnect rules with a licensed electrician—this card is educational screening only, not a stamped NEC 220 schedule.
For facility load roll-up, diversity factors, transformer and generator sizing, distribution planning, and power quality guides, use the Power Calculator hub (Power Factor featured topic). Conversion and cable tools stay on this page; load-to-equipment workflows start there.
It converts power values to current, sizes breakers and cables, checks voltage drop, and builds a practical baseline before detailed design and coordination studies.
How to calculate breaker and cable sizing in the right order?
Estimate load current first (from kVA or 3-phase inputs), select a breaker baseline, then validate cable ampacity and voltage drop—and iterate for consistency.
What is the difference between kW, kVA, and amps sizing?
kW is real power, kVA is apparent capacity, and amps validates cable and protection carrying limits on the feeder.
Where do fuse and MCCB decisions fit?
Use the Fuse vs Breaker Sizing Guide for device-class decisions; use the breaker calculator for amp screening on both fuses and breakers.
Should I use this hub or the Power Calculator hub?
Start on Power Calculator for factory load and equipment sizing; use this hub for conversion, protection, and cable checks on the same project.
