---
title: "Connected load, MD, demand factor, load factor"
subject: "Industrial Power Distribution and Illumination"
chapter: 1
key: "semester_6/industrial_power_distribution_and_illumination:define-connected-load-md-df-lf"
source: https://www.bctengineer.com/q/semester_6/industrial_power_distribution_and_illumination/define-connected-load-md-df-lf
site: BCT Engineering
---

# Connected load, MD, demand factor, load factor

Industrial Power Distribution and Illumination · Chapter 1: Introduction

- Asked in: 2068 Magh (old course), 8 marks
- Video: [Load Factor, Diversity Factor, Plant Capacity Factor, Utilization Factor, Reserve Capacity](https://www.youtube.com/watch?v=CeVFXs6mnUU) — Electrical Minus
- 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/define-connected-load-md-df-lf
- Whole chapter: https://www.bctengineer.com/md/semester_6/industrial_power_distribution_and_illumination/chapter-1

## Question

Define and elaborate with suitable example, "Connected load", "Maximum demand", "Demand factor" and "Load factor".

## Short answer

Connected load: total nameplate power (130 kW). Maximum demand: highest average load recorded (78 kW). Demand factor = MD/connected load = 78/130 = 0.6. Load factor = average load/MD; with 936 kWh per day, average load = 39 kW, giving load factor = 39/78 = 0.5.

## Answer

These four terms describe how the electrical capacity of an installation is used. A single example plant is used to show each.

**Example plant:** 6 motors of 15 kW, furnace 30 kW, lighting 10 kW.

#### Connected load
The sum of the rated (nameplate) powers of all equipment connected to the supply. It is the maximum the plant could draw if everything ran at full load together.
```text
Connected load = 6×15 + 30 + 10 = 130 kW
```

#### Maximum demand
The greatest load drawn during a period, measured as the highest average over a short interval (15 or 30 minutes) by an MD meter. Since machines run below rating and not all together, MD is less than the connected load. It decides the size of transformer, cables and switchgear, and the demand charge on the bill.
```text
Maximum demand recorded = 78 kW
```

#### Demand factor
The ratio of maximum demand to connected load. It is always ≤ 1 and is used to estimate MD at the design stage.
```text
Demand factor = 78 / 130 = 0.6
```
Typical values: motors 0.6–0.8, lighting about 1.

#### Load factor
The ratio of average load to maximum demand over a period (day, month, year). It shows how steadily the plant uses power.
```text
Energy used in a day = 936 kWh
Average load = 936 / 24 = 39 kW
Load factor  = 39 / 78 = 0.5
```
A high load factor means equipment is used well and the cost per unit of energy is low. Running some loads (pumps, furnaces) in off-peak hours raises the load factor.

| Term | Unit / range | Used for |
|---|---|---|
| Connected load | kW, kVA | Starting point of design |
| Maximum demand | kW, kVA | Sizing, demand charge |
| Demand factor | ≤ 1 | Estimating MD |
| Load factor | ≤ 1 | Cost and utilization |

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What is the connected load of 6 motors of 15 kW, a 30 kW furnace and 10 kW lighting?
   A. 130 kW
   B. 78 kW
   C. 120 kW
   D. 100 kW
   Answer: A. 90 + 30 + 10 = 130 kW. (Key point: Connected load)

2. How is maximum demand measured?
   A. Sum of nameplates
   B. Total energy divided by 24
   C. Lowest load of the day
   D. Highest average over 15 or 30 minutes by an MD meter
   Answer: D. MD is the highest average over a short interval. (Key point: Maximum demand)

3. With MD of 78 kW and connected load of 130 kW, what is the demand factor?
   A. 1.67
   B. 0.5
   C. 0.6
   D. 0.78
   Answer: C. 78/130 = 0.6. (Key point: Demand factor)

4. With 936 kWh per day and MD of 78 kW, what is the load factor?
   A. 0.6
   B. 0.5
   C. 12
   D. 2.0
   Answer: B. Average = 936/24 = 39 kW, and 39/78 = 0.5. (Key point: Load factor)

## Related in Industrial Power Distribution and Illumination

- [Connected load, MD, demand, diversity, load factor](https://www.bctengineer.com/question.md?key=semester_6%2Findustrial_power_distribution_and_illumination%3Aload-terminology-five-terms) — Industrial Power Distribution and Illumination, chapter 1
- [Load centre, connected load, maximum demand](https://www.bctengineer.com/question.md?key=semester_6%2Findustrial_power_distribution_and_illumination%3Aload-centre-connected-load-md) — Industrial Power Distribution and Illumination, chapter 1
- [Load factor and demand factor numerical](https://www.bctengineer.com/question.md?key=semester_6%2Findustrial_power_distribution_and_illumination%3Aconsumer-load-demand-factor) — Industrial Power Distribution and Illumination, chapter 1
- [Demand factor and diversity factor of substation](https://www.bctengineer.com/question.md?key=semester_6%2Findustrial_power_distribution_and_illumination%3Aload-centre-demand-diversity-numerical) — Industrial Power Distribution and Illumination, chapter 1