OHELE reference layer
Electrical Calculators and Calculation Guides
Use these guides to identify the assumptions, units and verification checks behind common electrical calculations. A calculator result is useful only when the circuit, equipment and operating conditions match the calculation.
Voltage Drop Calculation: Formula, Tables and Worked Examples
Voltage drop is the reduction in voltage along a conductor path while current flows. For a simplified resistance-only estimate, calculate the conductor resistance first,…
Calculating Maximum Demand kVA and Required Cable Current Rating
Maximum demand is not the sum of every connected load. It is the greatest demand expected over a defined assessment period after the applicable…
Cable Sizing for Circuit-Breaker-Protected Feeders: Six Verification Gates
For an LV feeder protected by a circuit breaker, choose a cable whose corrected current-carrying capacity covers the load and the breaker’s effective overload…
How to Size a Transformer: kVA Selection by Load Duty
To size a transformer, start with a documented load profile in kVA, then compare candidate ratings against the thermal, voltage, harmonic, motor-starting, fault and…
Battery Storage MW vs MWh: Calculate Duration Without Mixing Ratings
For battery energy storage, MW describes output power and MWh describes energy capacity. Their ratio gives duration in hours when both ratings use a…