Example of Scope of Works for Electrical Services

Below are the examples of Scope of Works for Electrical Services

a) Medium Voltage Distribution System
b) Low Voltage Distribution System
c) Standby Generator Set
d) Earthing System
e) Lightning Protection Installation
f) Light & Power Installation
g) Telephone System
h) Information Technology (ICT)
i) SMATV System
j) PA System
k) Security (CCTV System / IP Camera and Card Access System)
l) Parking System
m) Sound Reinforcement System
n) SMS System
o) External Lighting Installation
p) SMATV System

CALCULATION FOR EARTHING CABLE OF TRANSFORMER

Earth Fault Current = Rated Current / Impedence
where Rated Current = Rated KVA / (Rated KV x 1.732)


Example : 1600KVA TX , 11/0.433KV, Impedence : 6


--> Earth Fault Current = [1600KVA / (0.433 x 1.732] / 6
= 355.57A

Note :
To refer to catalogue to choose which size of cable that can carry 355.57A

Study Report 1 : Upgrading of Electrical Supply

1. Introduction:

To check the effect of load increase due to the new equipment to be installed in the factory

2. Reference Document:

a. as built drawings

b. latest electrical bill

c. on-hands information by the client's representative

3. Current installation:

a. Single chamber sub-station with 1000KVA Transformer

b. Current size of ACB is 1000A TPN with 1600A Busbar

c. Current MD is 600A

4. New Installation:

a. New equipment (MD = 720A)

b. New a/c load (MD = 86A)

5. Maximum Demand Load Analysis:

a. Future MD (A) = Current MD + New MD

= 600A + 720A + 86A

= 1406A

b. Future MD (KW) = 860KW

c. Future MD (KVA) = 1012KVA

6. Conclusion:

a. New load cannot be catered by existing TNB sub-station

b. Application on new load / increasing of the current load need to be submitted to TNB

c. New MSB need to be installed to cater for future load / to upgrade the existing MSB (1000A TPN ACB to 1600A TPN ACB)

Forms of Assemblies - FORM 4 (Part 4)

Note:
The above Form Code have been tabulated based on IEC 439-1, Part 1, Clause 7.7 - FORUM

Forms of Assemblies - FORM 3 (Part 3)

Note:
The above Form Code have been tabulated based on the IEC 439-1 Part1, Clause 7.7 - FORUM

Forms of Assemblies - FORM 1 & 2 (Part 2)

Note :

The above Form Code have been tabulated based on the IEC 439-Part 1, Clause 7.7 - FORUM

Forms of Assemblies (Part 1)

According to IEC 439-1, Clause 7.7 Forms of Assemblies can be obtained by means of partitions or barriers (metallic or non-metallic) into separate compartments or barriered sub-section.

Why is Forms of Assemblies is very important?

1. to enable a functional unit to remains in service - to reduce the risk of making accidential contact with the live part or adjacent units of busbars

2. to reduce the risk of loose part, tools, or even debris falling into or otherwise passing into an adjacent compartment

3. to limit the probability that ionised gas created by the operation of a short-circuit protective device, could cause flash over accross adjacent equipments or busbars

4. protection against contact with live parts belonging to the adjacent functional units

Note :

The above are a summarisation of Form Code IEC 439-Part 1, Clause 7.7 - FORUM