Assumption University
Thailand
EE4503
Electrical Systems Design
Load Calculation
1
Assumption University
Thailand
Topics
• Load Calculation (E.I.T.)
• Load Calculation by Adding Branch
Circuit
• Load Calculation for condominium
• Load Estimation
2
Assumption University
Thailand
Load Calculation (E.I.T.)
lighting
Building
Residential Area
Lighting (VA)
 2,000
> 2,000
Hospital
 50,000
> 50,000
Hotel, Condominium  20,000
20,001 – 100,000
> 100,000
Warehouse
 12,500
> 12,500
Other
Demand Factor (%)
100
35
40
20
50
40
30
100
50
100
3
Assumption University
Thailand
Load Calculation (E.I.T.)
receptacles
Non residential area
Total Load from Demand
Receptacle
Factor (%)
100
 10kVA
> 10kVA
Residential area
50
𝐿𝑚𝑎𝑥 + 0.4𝐿𝑟
4
Assumption University
Thailand
Load Calculation (E.I.T.)
Demand Factor of Appliances
Building
Residential
Area
Lighting (VA)
Kitchen
Hot Water
Air Condition
Office, Store Kitchen
Hotel, Other
Demand Factor (%)
10A+30% of extra
first two + 25% of other
100
First maximum device + 80% of
the second max. + 60% of the rest
Hot Water
100% of the largest + 25% of the
rest
Kitchen
Same as Office
Hot Water
Same as Office
Air Condition 75
5
Assumption University
Thailand
Load Calculation
by Adding Branch Circuit
• Add of all branch circuit
• Then multiply by the demand factor
Number of Panels
1
2-3
4-6
7-10
> 10
Demand Factor (%)
100
90
80
70
60
6
Assumption University
Thailand
Load Calculation
for Condominium
• Load: common area + individual room
Type
Residential
Number of Rooms Coincident Factor (%)
1-10
90
11-20
80
21-30
70
31-40
60
> 41
50
Non residential 1-10
100
> 11
85
7
Assumption University
Thailand
Load Estimation
• Quick estimate of the load
• Many common tables, just refer to one
8
Assumption University
Thailand
Load Estimation
http://static.schneider-electric.us/assets/consultingengineer/appguidedocs/section3_0307.pdf
9
Assumption University
Thailand
Load Estimation
http://static.schneider-electric.us/assets/consultingengineer/appguidedocs/section3_0307.pdf
10
Assumption University
Thailand
Load Estimation (E.I.T.)
lighting
Type
School
Computer Center, Meeting Room, Kitchen
Walk way, Balcony
Cafeteria
Hospital – Operation Room
Hospital – Patient Room
Office, Shopping Store
Drawing Room
Laboratory
VA/m2
25
20
8
18
100
14
30
60
50
11
Assumption University
Thailand
Load Estimation (E.I.T.)
receptacles
Type
Auditorium, Cafeteria, Church, Sport
Complex
Drawing Room
Hospital
Machine Room
Office
School
VA/m2
2
7
10
15
10
7
12
Assumption University
Thailand
Load Estimation (E.I.T.)
air condition
Type
Bank
Department Store
Hospital
Office
Grocery Store
Cafeteria
VA/m2
80
50
70
70
90
90
13
Assumption University
Thailand
Reference
• Electrical Systems Design: ประสิ ทธิ ์ พิทยพัฒน์
14