EpDc Building

A director of new small company at Kemayoran Jakarta presented me a isometric drawing as shown in Figure KBJ 1.1. He had a Civil Mechanical Electrical (CME) Building Project at EJIP Bekasi, He had designed all Civil and Mechanical by himself except the Electrical then tried me to design Electrical Construction. That was my first designing. The TL lamps on the Figure KBJ 1.1 are rectangular boxes, the box with 2x36 WATT each.
This Post shows some tricks of electrical consultant company to design electrical construction of  Public Houses, Goverment, Business , High Risk , and Industrial Building with limiting voltage 220V, 380V and 20KV, also Electrical Network Distribution Low Voltage and Medium Voltage.
( With f = 50 hz, PUIL standard is adopted from IEC, NEC Standard). Each problem and solution that  Autocad File ( Autocad 2009 version or above) is enclosed

Figure KBJ 1.1 Isometric View Building

The position of AC and Exhaust Fan are shown as figure KBJ 1.2. But the director didn't know how many WATT of them (.all these pdf file in high quality are suggested to download. )

Figure KBJ 1.2 Layout

Question : make the electrical construction of layout Figure KBJ 1.2.

Answer :
Follow these Steps:
Step 1 : Calculate the Total of Electrical Load in WATT unit , then convert into VA unit
Step 2 : Find the Main MCB and Main Cable refer to the Table or formula
Step 3 : Divide into several smaller groups ( Branch MCB ), then make the Single Line Diagram
Step 4 : Find the Grounding Cable on stick rod by formula
Step 5 : Describe  all groups  into Layout

Step 1 : Calculate the Total of Electrical Load in WATT unit , then convert into VA unit
By seeing figure KBJ 1.2 ,

a. The WATT of TL Lamp 2 x 36 WATT ----->  48 x ( TL Lamp 2 x36 WATT ) = 3456 WATT
b. The WATT of Exhaust Fan -----> 8 x 124 WATT = 992 WATT ( selected Exhaust Fan by searching google and ask for approval of the director )
c. The WATT of Loud Speaker -----> 1 x 400 WATT = 400 WATT ( selected Loud Speaker by searching google and ask for approval of the director )
d. The WATT of AC 2Hp -----> 6 x ( 2x 746 WATT ) = 11.936 WATT  ( 1 Hp = 746 WATT )
e. The WATT of Socket, we have to prepare sockets in case we need sometime  -----> 10 x 100 WATT = 1000 WATT

Total of Electrical Load in WATT = 3456 + 992 + 400 + 11.936 + 1000 = 17784 WATT

Convert WATT into VA -----------> VA = P/Cos Ø, where  P = Watt and Cos Ø = power factor,  In Indonesia the cos Ø usually about 0.85 or 0.8.
In this Blog we use Cos Ø = 0.8,  So, VA = P/Cos Ø = 17784/0.8 = 22230 VA

Step 2 : Find the Main MCB and Main Cable refer to the Table KBJ 1.a

NO	POWER ( VA )	MCB ( Ampere )	Main Cable	Phase Type
1	450	2	3 x 2.5 mm²	1Ø
2	900	4	3 x 2.5 mm²
3	1300	6	3 x 4 mm²
4	2200	10	3 x 4 mm²
5	3500	16	3 x 4 mm²
6	4400	20	3 x 4 mm²
7	5500	25	3 x 4 mm²
8	7700	35	3 x 6 mm²
9	11000	50	3 x 6 mm²
10	6600	3 x 10	4 x 4 mm²	3Ø
11	10600	3 x 16	4 x 6 mm²
12	13200	3 x20	4 x 10 mm²
13	16500	3 x 25	4 x 10 mm²
14	23000	3 x 35	4 x 16 mm²
15	33000	3 x 50	4 x 16 mm²
16	41500	3 x 63	4 x 25 mm²
17	53000	3 x 82	4 x 35 mm²
18	66000	3 x 100	4 x 50 mm²
19	82500	3 x 125	4 x 50 mm²
20	105000	3 x 160	4 x 70 mm²
21	131000	3 x 200	4 x 95 mm²
22	171000	3 x 250	4 x 120 mm²
23	197000	3 x 300	4 x 150 mm²
24	329000	3 x 500	4 x 240 mm²

Table KBJ 1.a  MCB and Cable Sizes  for Each Power ( VA)

Note :
The content of the table is adapted to the size of the MCB available in Indonesia Electrical Stores, or you can adjust the size of the MCB or Cable is available in your country by formula :

I = P / ( Vln x Cos Ø ) = VA / Vln       with Vln = V line netral = 220 Volt         …… for 1Ø
I = P / (1.73 x  Vll x Cos Ø ) = VA / ( 1.73 x Vll )    with Vll = V line line = 380 Volt  ...… for 3Ø

Example: A dozen lamps and 3 Electric Fan in your home with total 800 Watt,
So,  I = P ( Vln x cos Ø ) = 800 ( 220 x 0.85 ) = 4.3 Ampere, then you want to buy MCB at electric store, the clerk of the store simply  give you MCB 6 A, since MCB 4.3 A is not available at the store.

As described aboved that Rating Power 22230 VA associated with green color on the table KBJ 1.a , the main MCB is 3 x 35 Amperes type 3Ø, and and main cable is 4 x 16 mm²


Step 3 : Divide into several smaller groups ( Branch MCB ), then make the Single Line Diagram
For whom still don't know about 1Ø and 3Ø type can see illustrate of figure KBJ 1.3 below:

Figure KBJ 1.3 Illustrate of 1Ø and 3Ø types

As describe above, The Main MCB is 3 x 35 A type 3Ø but we have to divide the MCB 3Ø into 3 pieces of MCB 1Ø they are  MCB 35A 1Ø, MCB 35A 1Ø, MCB 35A 1Ø, but MCB 35A isn't abailable in Indonesia Electrical Store instead 40A, so we have to provide the main MCB 3x40A which 3Ø and 3 of MCB 40A type 1Ø.

See the single line diagram at Figure KBJ 1.4 below which contain of Figure KBJ 1.4a and Figure KBJ 1.4b.  At Figure KBJ 1.4a only a line is used for 23000 VA , but of course we can use the other 2 line  with different KWH Meter. Refer to figure KBJ 1.4 a and b, the MCB 16 A is a higher MCB for load distribution so we get the better choice of single line diagram as shown Figure KBJ xx .

Figure KBJ 1.4 Single Line Diagram

Figure KBJ xx Alternative choice single line diagram

Step 4 : Find the Grounding Cable on stick rod by formula
Grounding Cable sizing ( usually BC Type )  that connected to stick rod is found as follows:
if S ≤ 16 mm² ,  so BC grounding’s size is S mm²
If 17 mm² ≤  S ≤ 35 mm³ , so BC grounding’s size is only 16 mm²
But if S ≥ 35 mm² , BC grounding’s size is S/2
Where S = Cable Size
So, according this equation, we got BC cable grounding that connected to stick rod about BC 16 mm²

Step 5 : Describe  all groups  into Layout
If we put all groups at once that would look be over crowded so we put one by one as shown Figure KBJ 1.5a, 1.5b and 1.5c below :

Figure KBJ 1.5a Construction for Group A

Figure KBJ 1.5b Construction for Group B

Figure KBJ 1.5c Construction for Group C

 NOTE :

Try to look the single line diagram of figure KBJ 1.5a, the both cable sizes of MCB 16A and 10A is NYM 3x4 mm2, that's not mean we have to use this size into electrical load because of too expensive, we need cheaper but secure or safety. We can divide them into several smaller size of MCB like sevral MCB 6A or 2A. Again we can divide the by ignoring MCB 6A or 2A with only using Cable 2.5 mm2 as shown in Figure KBJ 1.5a, 1.5b and 1.5c. Some Lamps and Electrical Motor 1Ø (the sample of Motor 1Ø are Fan, Refrigerator, water pump at home, ironing, hand drier, etc ) are using cable NYM or NYY 2x2.5 mm2 or 3x2.5 mm2. For figure KBJ ....you can see that lamps and Exhaust Fan are similar. The Lamps and Exhaust Fan is combineed in paralel since they have  WATT number less than 1500 WATT. But you can't do the same way using 2.5mm2 size into some AC, each AC has number WATT greater rhan 1500 WATT, we have to make wiring each AC separately. The only way to make them a paralel combine is by using 3x4 mm2 cable size.
The Lamps using cable 2x2.5 mm2 but socket using cable 3x2.5 mm2, The number 3 of socket is related to grounding if you still don,t know about this grounding on socket, you can see the illustration of Figure KBJ 1.6. Cable NYM is indoor cable type and has white color of cover, we can install this cable at home with or without pipe. The NYY type is outdoor cable and has black color of cover, we can use this cable as underground cable with put into pipe. Cable NYFGBY type is specialize underground cable without using pipe. KWH meter is usually placed  outdoor 1.8 meter high from floor and must be easy to be reach by electrical technician company. Panel is usually placed  indoor 1.6 meter high from floor and mus be easy to be reach by owner's house. Socket and Switch is usually placed  indoor 1.2 meter high from floor near rooms or doors and but the switch or socket is not hidden or covered while we open the door,You can download Autocad File version here of the PDF fictures above if you need to

Figure KBJ 1.6 Socket use 2 line and Lamp uses 3 line for wiring