Electrical installations require a solid understanding of various electrical formulas, whether in residential or commercial settings. These formulas are essential for ensuring electrical systems’ safety, efficiency, and reliability. This article provides a comprehensive overview of commonly used electrical formulas, along with explanations and practical tips for their application.

### Commonly Used Electrical Formulas

Quantity | Formula | Unit | Description |
---|---|---|---|

Power (Single Phase) | P = V × I | Watts (W) | Power is the product of voltage (V) and current (I). |

Power (Three Phase) | P = √3 × V × I × PF | Watts (W) | Power in a three-phase system is the product of √3, voltage (V), current (I), and power factor (PF). |

Current (Single Phase) | I = P / V | Amperes (A) | Current is the power (P) divided by voltage (V). |

Current (Three Phase) | I = P / (√3 × V × PF) | Amperes (A) | Current in a three-phase system is the power (P) divided by the product of √3, voltage (V), and power factor (PF). |

Voltage | V = P / I | Volts (V) | Voltage is the power (P) divided by current (I). |

Resistance | R = V / I | Ohms (Ω) | Resistance is the voltage (V) divided by current (I). |

Ohm’s Law | V = I × R | Volts (V) | Voltage is the product of current (I) and resistance (R). |

Power Factor | PF = P / (V × I) | Unitless | Power factor is the ratio of real power (P) to the apparent power (V × I). |

P = 230 V × 10 A = 2300 W

P = 1.732 × 400 V × 20 A × 0.8 = 11,091.2 W

I = 2000 W / 230 V ≈ 8.7 A

I = 10000 W / (1.732 × 400 V × 0.9) ≈ 16.0 A

V = 1500 W / 6.5 A ≈ 231 V

R = 220 V / 10 A = 22 Ω

V = 5 A × 10 Ω = 50 V

PF = 5000 W / (230 V × 25 A) ≈ 0.87

### Practical Tips for Using Electrical Formulas

**Accuracy in Measurements**: Ensure that voltage, current, and resistance measurements are accurate to obtain reliable results from the formulas.**Safety First**: Always follow safety protocols when working with electrical systems to prevent accidents and equipment damage.**Use Proper Units**: Consistently use the correct units for each quantity to avoid calculation errors.**Double-Check Calculations**: Verify your calculations to ensure they are correct, especially in critical installations.**Consult the Professionals:**If unsure it’s better to consult licensed electrical practitioners PEE, REE, or RME.

### Conclusion

Understanding and applying these electrical formulas is essential for anyone involved in residential and commercial electrical installations. These formulas help in designing, troubleshooting, and ensuring the safety and efficiency of electrical systems.

For further reading and more detailed examples, consulting other resources such as the International Electrical Code Standards (IEC), NEC, PEC, and other International Electrical Standards can provide additional insights and guidelines.