--- title: "Short note: Factor of maximum utilization Ku" subject: "Industrial Power Distribution and Illumination" chapter: 1 key: "semester_6/industrial_power_distribution_and_illumination:short-note-ku" source: https://www.bctengineer.com/q/semester_6/industrial_power_distribution_and_illumination/short-note-ku site: BCT Engineering --- # Short note: Factor of maximum utilization Ku Industrial Power Distribution and Illumination · Chapter 1: Introduction - Asked in: 2073 Bhadra, 2 marks - Video: [6. DIVERSITY FACTOR, COINCIDENCE FACTOR, CAPACITY , UTILISATION FACTOR & PLANT USE FACTOT](https://www.youtube.com/watch?v=TWDcwSwv504) — Electrical Tutorial - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_6/industrial_power_distribution_and_illumination/short-note-ku - Whole chapter: https://www.bctengineer.com/md/semester_6/industrial_power_distribution_and_illumination/chapter-1 ## Question Write a short note on factor of maximum utilization (Ku). ## Short answer Factor of maximum utilization (ku) = actual maximum power used / rated power (ku ≤ 1). Accounts for equipment not running at full rating (e.g., motors at 0.75, lighting/heating at 1). Applied per load before simultaneity factor ks. Example: 10 kVA motor with ku=0.75 counted as 7.5 kVA for board demand calculation. ## Answer The **factor of maximum utilization (ku)** is the ratio of the maximum power actually taken by a load in normal operation to its rated (installed) power: ```text ku = Actual maximum power used / Rated power (ku ≤ 1) ``` It is used in industrial load estimation (IEC method) because equipment rarely runs at full rating. For example, a motor is chosen with a margin and usually runs at about 75% of its rating. **Typical values:** - Motors in industry: ku ≈ 0.75 - Incandescent lighting and heating: ku = 1 - Socket outlets: depends on what is plugged in **Example:** a 10 kVA motor with ku = 0.75 is counted as 7.5 kVA when the demand of its distribution board is worked out. ku is applied to each individual load, before the factor of simultaneity ks is applied to groups. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. What is the factor of maximum utilization? A. Ratio of group MD to sum of individual MDs B. Ratio of average to maximum demand C. Ratio of connected load to MD D. Ratio of the maximum power a load actually takes to its rated power Answer: D. ku = actual maximum power used / rated power, at most 1. (Key point: Definition of ku) 2. Which typical ku values are used? A. Motors 1; lighting 0.75 B. Motors 0.2; lighting 0.2 C. Motors about 0.75; incandescent lighting and heating 1 D. All loads 0.5 Answer: C. Motors usually run below rating, while lighting and heating run at full rating. (Key point: Typical values) 3. A 10 kVA motor with ku = 0.75 is counted as how much? A. 13.3 kVA B. 7.5 kVA C. 10.75 kVA D. 0.75 kVA Answer: B. 10 x 0.75 = 7.5 kVA. 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