Connected load in an industry

Connected load is the sum of the rated (nameplate) powers of all electrical equipment connected to the supply system of an industry, expressed in kW or kVA.

In an industry it includes:

• Motors of machines, pumps, fans, compressors, cranes and conveyors
• Heating loads such as furnaces, ovens, boilers and welding sets
• Lighting (lamps with ballast/driver losses) and fans
• Socket outlets and office equipment
• Air conditioning and other building services

Points to note:

• Connected load is not the load the plant actually draws. Machines run below full rating and not all at once, so the actual maximum demand is less (demand factor = MD / connected load, typically 0.5–0.8 in industry).
• It is the starting point for load estimation: maximum demand is found from it using demand and diversity factors (or ku and ks).
• The utility uses it to classify the consumer and to approve the connection.

Example: a small factory has 10 motors of 7.5 kW, 2 furnaces of 20 kW, 60 lamps of 40 W and 4 kW of office load.

Connected load = 10×7.5 + 2×20 + 60×0.04 + 4
               = 75 + 40 + 2.4 + 4
               = 121.4 kW