Distribution
Electrical Load Calculator
Build connected and diversified load schedules for boards and feeders.
Load current calculation
Applicable references
Bangladesh National Building Code
National building code covering electrical installations, safety and building services requirements in Bangladesh.
Bangladesh National Building Code
Referenced as an applicable installation code; no specific clause number is claimed.
National Electrical Code
Referenced as an applicable installation code; no specific clause number is claimed.
Source
Method, formulas and limitations
Formulas used
- Apparent power
- S (kVA) = P (kW) ÷ power factor. The connected load is the unit load multiplied by the quantity you enter.
- Single-phase current
- I = S × 1000 ÷ V, where V is the line-to-neutral (or single-phase) voltage you enter.
- Three-phase current
- I = S × 1000 ÷ (√3 × V), where V is the line-to-line voltage you enter.
- Optional load factor
- When you explicitly supply a verified load, demand or diversity factor, the diversified load is simply connected load × factor. No factor is applied unless you enter one.
What this version does not model
- Demand/diversity factors: OHMICLY does not apply automatic demand or diversity factors. Enter one only if your applicable standard or project data supplies it.
- Motor loads: Running current is calculated from the kW and power factor you supply. Motor starting (locked-rotor) current, efficiency, service factor and power-factor correction are outside the scope of this tool.
- Harmonics and non-linear loads: The calculator uses a single power factor and does not estimate harmonic currents or K-factor loading.
- Code compliance: This tool does not check ampacity, voltage drop, protection coordination or any other code requirement. Those checks must be performed separately against the standard applicable to your installation.
About this load calculation
This calculator turns a load's real power (kW), system voltage and power factor into the apparent power (kVA) and line current needed to size cables, breakers and distribution equipment. It handles single-phase and three-phase circuits using the standard power relationships, and it can multiply a single load by a quantity to give a total connected load.
The result is the running current under the conditions you enter. It is not a demand load unless you supply a verified load or diversity factor from your applicable standard. The calculator deliberately does not apply automatic demand factors, diversity factors or code loading values — those vary by country, occupancy and installation type, and must come from the engineer or the standard being used.
For motor loads the running current is calculated from the kW and power factor you provide. Motor starting (locked-rotor) current, efficiency, service factor and power-factor correction are not modelled. If you are selecting a motor feeder, perform the starting-current and protection-coordination checks separately.
Formula notes
- Apparent power S (kVA) = P (kW) ÷ power factor.
- Single-phase current I = S × 1000 ÷ V.
- Three-phase current I = S × 1000 ÷ (√3 × V), using the line-to-line voltage.
- Total connected load = unit load power × quantity.
- A user-supplied load/diversity factor is applied only when explicitly entered; OHMICLY does not apply automatic demand or diversity factors.
- Motor starting current, efficiency, service factor and power-factor correction are not modelled in this version.
Worked example — connected load on a sewing-line distribution board
Scenario
- Three-phase 400 V distribution board on a garment production floor
- Connected real power 10 kW per unit at a power factor of 0.9
- Quantity 1 (increase the quantity to total several identical loads)
- Load factor left blank unless your standard gives you one
Steps, using the formulas on this page
- 1. Connected loadP = unit load × quantity
- 2. Apparent powerS = P ÷ power factor
- 3. Three-phase line currentI = S × 1000 ÷ (√3 × V)
The current returned is the running current for the values entered. It becomes a demand load only when you apply a load or diversity factor taken from the standard applicable to your project.
Bangladesh practice — common questions
- Does this calculator apply Bangladesh demand or diversity factors automatically?
- No. Demand and diversity factors depend on occupancy and installation type and are published in the code your project is assessed against, such as the Bangladesh National Building Code electrical provisions. OHMICLY applies only the load factor you enter yourself, so the connected-load figure stays traceable to your own source.
- Is the motor current shown here suitable for sizing a motor feeder?
- It is the running current only. Motor starting (locked-rotor) current, efficiency and service factor are not modelled, and starting behaviour usually governs both protection settings and voltage drop on garment-factory motor circuits. Carry out the starting-current and protection-coordination checks separately.
Related audit resource
RSC & Nirapon audit resourcesLoad schedule and distribution board templates aligned with RSC and Nirapon electrical audits.Browse resourcesFrequently asked questions
- What does the Load Calculator compute?
- It calculates apparent power (kVA), load current (A) and total connected load from the real power (kW), voltage, phase arrangement, power factor and quantity you enter. If you supply a verified load or diversity factor, it also shows the diversified load.
- Does it apply demand or diversity factors automatically?
- No. OHMICLY does not hold verified demand/diversity tables for every country and installation type, so no factor is applied unless you explicitly enter one from your applicable standard.
- Can I use this for motor feeders?
- The calculator gives running current only. Motor starting (locked-rotor) current, efficiency, service factor and power-factor correction are not modelled. Size motor feeders and protection separately.