EpDc Industrial Site

In October 2014, we were the small contractor employees surveyed a location of new candidate electrical project at Waste Processing Plant in Bogor Indonesia. The Chief engineer (Owner) of the Waste Processing Plant took us to look around the location, where the location would be used as the expansion of the electrical network were located approximately 900 m from the nearest power source ( POWER DISTRIBUTION SUBSTATION ). He started at point 1 with ended at point 4 as shown in Figure 1.1 below:

Figure plpi 1.1 Location

He needed the cable from point 1 to the point 2 to be underground cables where point 1 is the Power Distribution Substations with MCCB 400A on LVMDP. This MCCB 400A would be the main source of the whole Electrical Network Distribution plus the engineer said that Generator is added for Back up source with COS ( Change Over Switch )

Point 2 is planned to be a new panel with some MCBs FUJI brand.The Indonesian Contractors Employees are familiar with Scheneider brand but although the engineer was Indonesia native should use Fuji brand because of factory owners are Japanese. The point of no 3 at the Figure 1.1 is the existing panel that several MCCBs within panel will be modified . At last from point 3 to point 4 is the overhead electrical distribution network with a total of 10 pieces of electric poles. At the end of the Electric Pole there is a new panel that would supply a spot light on each after second Electrical Pole plus 7 pieces of 3Ø Pumps 3.7 KW each. The several of  Electrical Material are shown in Figure plpi 1.2. He wanted us to design electrical and expected to be completed no later than one week.

Figure plpi 1.2 Layout

As a contractor we will certainly work hard otherwise we would lose that job. By working mightily finally we completed our task. Previously in EPDC HOUSE and EPDC EXAMPLES INDUSTRIAL /BUSINESS there are five stages sequence that we had to do for designing of electrical construction, but in this case the stage is not applicable because the engineer couldn’t decide with certainty any electrical device that will be installed at the end point (point 4). Of course we obeyed his will by reason of job opportunities and money.

The Electrical Construction is described as follows:
Step 1: Build each panel at point no 1,2,3 and 4
Step 2: Determine cable type and size between each point
Step 3: Determine physics construction each and between point
Step 4: Combine them in layout

We will do step by step.

Step 1:

Panel A : Panel inside Power Distribution Substation at Point no 1 is named LVMDP ( Low Voltage Main Distribution Panel ) which have 2 MCCB 400A each as output. The Chief Engineer asked us to use one of the both MCCBs as main source then add COS which switch other source ( generator ) in case failure supply.

Panel B : There are two MCCB 3Ø 250A and six MCCB 3Ø. All MCCBs must be arranged starting from higher MCCB followed by the lower.

Panel C : MCCB 3Ø 150A and 100A are replaced by MCCB 3Ø 250A and 200A.

Panel D : Panel will supply 7 motors 3.7 Kilo watt and spotlight 1500Watt

  

We often see the size main MCCB panel become smaller than the sum of MCCB branch , this is not a problem because of the use of load simultaneity can only 60% or 70 %, for example in panel D : MCCB 100A has 6 sub MCCB 20A .

Panel A, B, C dan D which are to be design shown in Figure plpi 1.3

Figure plpi 1.3 Single Line Diagram

Step 2: cable type and size between each point

NO	POWER ( VA )	MCB ( Ampere )	Main Cable
1	450	2	3 x 2.5 mm²
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
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
25	414000	3 x 630	4 x 300 mm²

Table 1.a 

Cable between Panel A and B.
The cable size of MCCB 400A as a source in Panel A is between row no 23 and 24 in Tabel 1.a above ( blue color ). There is no NYY 4 x 270 cable available at electrical store . The best choice is 4 x 240 mm² but the chief engineer didn’t like it with reason quite difficult to be installed, then we choose double cable of NYY 4 x 195 mm². If it double cable, the size cable of 195 become 2x195 = 390 mm². It means cable become stronger , higher rating ampere and easier to be installed. Underground NYY cable type is have to use pipe AW type, the other choice is using NYFgbY type without pipe. In this case Chief Engineer approved NYFGbY type.

Cable between Panel B and C.
The source for current distribution to Panel C is MCCB 250A on Panel B. According to Table 1.a above, the cabel is NYY 4 x 120 mm² and would be distributed via tray.

Cable between Panel C and D.
Overhead distribution using Overhead Aluminium Cable, NFA2X 3 x 70 mm² + 1x 50 mm²
Type Aluminium. MCCB vs Twisted Cable ( Aluminium) as shown in Table 1.b

NO	MCB ( Ampere )	Main Cable
1	125	35 mm²
2	125	50 mm²
3	200	70 mm²

Table 1.b

Ten spotlights Total 1500 Watt. Each spotlight has 15 Watt and each second pole has 2 spotlight as shown in Figure plpi 1.4. Actually, the Lamps can be connected to a twisted cable using Photocell Switches , but the owner prefers Timer Switch in panel D so we add cable NYY.

Figure plpi 1.4  

Spotlight Cable

We usually found cable 2.5 mm² is connected to several lamps but concerning distance 400 m between EP1 and EP10, it’s necessary to calculate drop voltage, so we get the better cable size

Drop voltage while Lamps 1500 Watt is connected as shown in figure plpi 1.4 can be found according to formulas :

DROP VOLTAGE FORMULAS

Light or lamp is suggested drop voltage 2%, but in this case owner need higher quality voltage with drop voltage about 1.15% or (1.15%x220V) =2.5 Volt. If max drop voltage = 2.5 V, Find Cable size of Spottlight 

Refer to equation 2 in FORMULAS: q = (2L x P)/(V x ∆V x λ)

We get : ∆V = (2L x P)/(V x λx q)

And refer to Figure plpi 1.4 :

∆V9 = (2L x P)/(V x λx q) = (2L9 x P)/(220 x 56 x q)= (2.40 x 5.30)/(220.56.q) = (80 x 150)/(12320.q)=0.97/q

∆V7 = (2L x P)/(V x λx q) = (2L7 x P)/(220 x 56 x q)= (2.80 x 4.30)/(220.56.q) = (160 x 120)/(12320.q)=1.56/q

∆V5 = (2L x P)/(V x λx q) = (2L5 x P)/(220 x 56 x q)= (2.80 x 3.30)/(220.56.q) = (160 x 90)/(12320.q)=1.17/q

∆V3 = (2L x P)/(V x λx q) = (2L3 x P)/(220 x 56 x q)= (2.80 x 2.30)/(220.56.q) = (160 x 60)/(12320.q)=0.78/q

∆V1 = (2L x P)/(V x λx q) = (2L1 x P)/(220 x 56 x q)= (2.80 x 30)/(220.56.q) = (160 x 30)/(12320.q)=0.78/q=0.39/q

Then, ∆V = ∆V9 + ∆V7 + ∆V5 + ∆V3 + ∆V1  with ∆V= 2.5 Volt

2.5 = ∆V9 + ∆V7 + ∆V5 + ∆V3 + ∆V1  =  0.97/q + 1.56/q + 1.17/q + 0.78/q + 0.39/q = 4.87/q

So, q = 4.87/2.5 = 1.9 mm² ≈ 2.5 mm² or Cable NYY 2x2.5 mm² outdoor cable, if indoor type NYM.

Motor 3Ø (3.7KW) Cable
In order to find cable size of motor 1Ø or 3Ø, we need to calculate I(Ampere) of the motor first, with formulas:

Table 1.b MCB For Motor

I = P/(1.73 x VLL Cos Ø)= 3700/(1.73 x 380 x 0.85)= 6.6 A

MCB = 250% X 6.6 = 16.5 A ≈ 20 A
Regarding the relay or the motor sensor is an electronic parts so it is not discussed here.

Step 3 :
Physics Construction Between Point no 1 and 2 is Underground Cable NYFGbY 2x(4 x 95) mm² with length 280 M. Every Outdoor Panel is suggested using Grounding with R≤ 5 Ω.  EP use Grounding every 200 meter or every 5 EP with R ≤ 10 Ω. Grounding on EP is made every 200 meter but in this case grounding is placed on EP1 and EP10. Grounding on Panel is similar to EPDC Industrial/Business Example 1
The Complete Construction or detail is shown in As Built Drawing in Figure plpi 1.5 include Autocad File ( 2009 Version or above) here.