Electrical Cables and Conductors National Certificate I PDF

FACILITATING AND LEARNING MATERIAL FOR ELECRICAL ENGINEERING TECHNOLOGY PROGRAMME **National Certificate I** **CABLES AND BARE CONDUCTORS** **This facilitating and learning material covers all the Learning Outcomes for Cables and bare conductors for the National Certificate I programme** ![](med...

FACILITATING AND LEARNING MATERIAL FOR ELECRICAL ENGINEERING TECHNOLOGY PROGRAMME **National Certificate I** **CABLES AND BARE CONDUCTORS** **This facilitating and learning material covers all the Learning Outcomes for Cables and bare conductors for the National Certificate I programme**  **UNIT--9** LEARNING OUTCOMES ================= **1** **Demonstrate knowledge of electrical cables.** ------- ------------------------------------------------------------------ **2** **Demonstrate knowledge of types electrical cables.** **3** **Demonstrate skill in using electrical cables and conductors.** No Table of Contents Page ------ -------------------------------------------------------------------------- ------ 1 Introduction 3 LO1 **Demonstrate knowledge of cables** 5 PC a Explain cables PC b State types of cables PC c Identify colour codes of cables PC d Explain importance of using cable colour codes Self-assessment References LO2 **Demonstrate knowledge of types of cables** 10 PC a Explain cables PC b State types of cables PC c Outline sizes of cables PC d Identify colour codes of cables PC e Explain importance of using cable colour codes Self-assessment activities References LO3 **Demonstrate skill in using electrical cables and conductors** 16 PC a Select correct size of electrical cables and conductors for a given task PC b Select a particular colour of cable for a given task PC c Use cables and conductors for a given task PC d Adhere to safety practices Self-assessment activities References **1.0 Introduction and Preliminary Notes** In this unit, you will learn about electrical cables. After the learning, you will be able to explain electrical, state the types of cables and identify color code of electrical cables. The knowledge gained about conductors and cables will lead you to be able to apply electrical cables and conductors to a given task This learning material should be used with the unit specification given as the unit specification will guide you on the standards stated with all the range statements. You should also be guided by the evidence requirements so that your learning is relevant to the required standards. The way the learning material is written is to encourage learner autonomy and initiative (i.e., activities that require the learner to work independently of the facilitator and to make decisions concerning how he/she might approach a task) so that you as a learner can take ownership of your own learning. Follow the instructions and the steps indicated in the learning material and work as independently as possible. Table1: Icons and their Meaning +-----------------------+-----------------------+-----------------------+ | ICONS AND THEIR MEANI | | | | NGS | | | | ===================== | | | | === | | | +=======================+=======================+=======================+ | **\#** | **Icon** | **Meaning** | +-----------------------+-----------------------+-----------------------+ | 1 | j0293844 | Learning Outcome | +-----------------------+-----------------------+-----------------------+ | 2 |  | | +-----------------------+-----------------------+-----------------------+ The meaning of each icon is provided in Table 1. You should know what each icon represents. Carefully observe the icons and their meanings. Congratulations on going through the icons and their meanings! We will next look at the activities under LO 1. LO 1 Demonstrate knowledge in electrical conductors.  ========================================================================== This LO is developed to help you acquire knowledge in electrical conductors. ============================================================================ To achieve this, you will go through PCs (a) -- (d). In this learning session, you will be learning the basics, before you proceed, you have to explain the term electrical conductor. **PC (a) Explain electrical conductor** --------------------------------------- A conductor is a material which allows electrical current to flow through it. Examples of conductors are metals like copper, aluminium and their alloys. In an electrical conductor, the electric charges move from atom to atom when the potential difference is applied across it. Figure 1 shows a conductor. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- **PC (b) State types of Conductors** ------------------------------------ In the previous PC you learnt about the conductor. This PC will introduce you to types of conductors. There are various types of electrical conductors but for this PC, we will consider the following types: 1. 2. 3. 4. **PC (c) Explain types of conductors** As you have learnt about the types of conductors in the previous PC, it is time to also explain the types of conductors. 1. This type of conductor has high tensile strength, high electrical conductivity, long life, and high scrap value. It is most suitable for distribution work where spans and tapping are more. Figure 2 shows a Hard drawn copper conductor.  2. This type of conductor is a mixture of copper and cadmium. The tensile strength of the copper is increased by approximately 50 percent by adding about 0.7 to 1.0 percent cadmium to it, but the conductivity is reduced by about 15 to 17 percent. The property of higher tensile strength enables the conductor to be erected on longer spans with the same sag. This conductor possesses the advantages of easy joining, more resistance to atmospheric condition, better resistance to wear, easy machinability, etc. Figure 3 shows the picture of cadmium copper conductor. 3. The cost of the copper conductor is very high, and hence it is replaced by the aluminium conductor. The handling, transportation and erection of aluminium wires is very economical. It is used in distribution lines in the urban area and short transmission line with the lower voltages. Figure 4 shows a picture of Hard-drawn aluminium conductor.  4. In steel cored copper conductor one or two layers of copper strands surround a steel cored copper conductor. The steel core increases the tensile strength of the conductor. Figure 5 shows a steel-cored copper conductor **PC (d) Explain importance of using conductors** This PC is developed to let you understand the importance of using conductors. Conductors are important because they find use in many real-life applications. For example: 1. 2. 3. 4. 5. **Self-Assessment 1** This learning outcome (LO) has a little quiz at the end. I recommend you take this whole quiz without looking back for any of the answers. This is meant to help you determine how well you have understood this learning outcome. Now assess yourself with the questions below: 1. A material which allows electrical current to flow through it is termed \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_. 2. Mention three types of conductors? 3. State two properties of cadmium copper conductor. 4. Two applications of conductors are: LO 2 Demonstrate knowledge in electrical cables. ================================================ This LO is developed to help you acquire knowledge in electrical Cables. ======================================================================== To achieve this, you will go through PCs (a) -- (e). In this learning session, you will be learning the basics, before you proceed, you have to explain the term electric Cable. **PC (a) Explain cables** ------------------------- An electric cable is a conductor or group of conductors for [transmitting](https://www.britannica.com/dictionary/transmitting) [electric power](https://www.britannica.com/technology/electric-power) or telecommunication signals from one place to another. ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Electric communication cables transmit voice messages, computer data, and visual images through electrical signals to telephones, wired radios, computers, teleprinters, facsimile machines, and televisions. There is no clear distinction between an electric wire and an electric cable. Usually the wire refers to a single, solid metallic conductor, with or without insulation, while the latter refers to a stranded conductor or to an assembly of insulated conductors. Figure 6 shows a cable.  **PC (b) State types of electric cables** ----------------------------------------- In the previous PC we learnt about the conductor. The PC will introduce you to types of conductors. There are various categories of cables but for this PC, we will consider the categories of cables shown in Table 1: **\#** **Cable** **Image** -------- ------------- ------------------------ 1 Single core 2 2 Core  3 3 Core 4 4 Core  **PC (c) Outline sizes of cables** This PC is developed to let you outline the sizes of cables. There are various sizes of cables but for this PC, we will consider the sizes of cables shown in Table 2.. **\#** **Cable Size** -------- ------------------------ 1 2  3 4  5 6  **PC (d) Identify colour codes of cables** As you have learnt about the types of cables and their sizes, it is time to also learn about the color codes of the types of cables. There are many wire identification standards, and many of them rely on color codes. Table 3 presents the international standard color codes for electrical cables. +-----------------------+-----------------------+-----------------------+ | **Cable** | **Image** | **Colour code** | +=======================+=======================+=======================+ | Single core | | Blue or Brown or | | | | Yellow | +-----------------------+-----------------------+-----------------------+ | 2 Core |  | Brown -- Line | | | | | | | | Blue -- Neutral | +-----------------------+-----------------------+-----------------------+ | 3 Core | | Brown -- Line | | | | | | | | Blue -- Neutral | | | | | | | | Green/Yellow -- | | | | Ground | +-----------------------+-----------------------+-----------------------+ | 4 Core |  | | | | | Black -- Line | | | | | | | | Gray -- Line /Neutral | | | | | | | | Green/Yellow -- | | | | Ground | +-----------------------+-----------------------+-----------------------+ **PC (e) Explain importance of using cable color codes** This PC presents the importance of using electrical cable colour codes. Electric cable color code is an internationally accepted form of communication among Electricians. The color codes of electric cables are set in place to ensure that the wiring on an installation is correct to prevent shock and damage to equipment. The codes on the cable defines which conductor is ground, neutral and line for proper connection to supply and equipment. **Self-Assessment 1** This learning outcome (LO) has a little quiz at the end. I recommend you take this whole quiz without looking back for any of the answers. This is meant to help you determine how well you have understood this learning outcome. Now assess yourself with the questions below: 1. 2. 3. LO 3 Demonstrate skill in using electrical cables and conductors.  ======================================================================================= This LO is developed to help you acquire skill in using electrical Cables and conductors. ========================================================================================= To achieve this, you will go through PCs (a) -- (c). In this learning session, you will be learning the basics, before you proceed. **PC (a) Select correct size of electrical cables and conductors for a given task** In the previous LO you learnt about cable sizes. This PC is developed to let you select the correct sizes of cables for a given task. Generally, different electrical cable sizes have distinct uses due to variations in their current carrying capacity. Table 4 shows a list of tasks and the appropriate cable sizes to perform them. +-----------------------+-----------------------+-----------------------+ | **\#** | **Cable Size** | **Task** | +=======================+=======================+=======================+ | 1 | | Lighting circuitry | | | | and switches | +-----------------------+-----------------------+-----------------------+ | 2 |  | socket wiring | +-----------------------+-----------------------+-----------------------+ | 3 | | High power ring | | | | mains, plug and | | | | socket wiring | +-----------------------+-----------------------+-----------------------+ | 4 |  | Mains supply | | | | electricity, cooker | | | | circuits | +-----------------------+-----------------------+-----------------------+ | 5 | | Shower installations, | | | | cooker circuits. | +-----------------------+-----------------------+-----------------------+ | 6 |  | - Garden Lighting. | | | | | | | | - Factory Lighting. | | | | | | | | - LED Garden | | | | Lighting. | | | | | | | | - Electric Gates. | | | | | | | | - Security | | | | Lighting. | +-----------------------+-----------------------+-----------------------+ The checklist below will be used to assess your learning **Check List 1: Selecting task according to cable sizes** ----------------------------------------------------------- ----------------------- ----- ---- No Yes No 1 Select task for 1.5mm 2 Select task for 2.5mm 3 Select task for 4mm 4 Select task for 6mm 5 Select task for 10mm 6 Select task for 16mm **PC (b) Select a particular color code of cable for a given task** This PC is developed to let you choose the appropriate colour code for a given task on a cable. The task performed by a particular code of a cable sometimes depends on the type of cable. Table 5 shows the color code of cables and their task. +-----------------+-----------------+-----------------+-----------------+ | **Cable type** | **Image** | **Colour code** | **Task** | +=================+=================+=================+=================+ | Single core | | Brown/Blue/ | Line/neutral/ | | | | Black/Yellow | Earth | | | | | | | | | | (single Phase) | +-----------------+-----------------+-----------------+-----------------+ | 2 Core |  | | | | | | Blue | Blue -- Neutral | | | | | | | | | | (single Phase) | +-----------------+-----------------+-----------------+-----------------+ | 3 Core | | Brown | Brown -- Line | | | | | | | | | Blue | Blue -- Neutral | | | | Green/Yellow | | | | | | Green/Yellow -- | | | | | Ground | | | | | | | | | | (single Phase) | +-----------------+-----------------+-----------------+-----------------+ | 4 Core |  | | | | | | Black | Black -- Line | | | | | | | | | Gray | Gray -- Line | | | | | /Neutral | | | | Green/Yellow | | | | | | Green/Yellow -- | | | | | Ground | | | | | | | | | | (three Phase) | +-----------------+-----------------+-----------------+-----------------+ The checklist below will be used to assess your learning **Check List 2: Select cable color code for a given task** ------------------------------------------------------------ ---------------------------------------------------------------------------------------- ----- ---- No Yes No 1 Single core: Brown/Blue/ Black/Yellow - Line/neutral/ Earth 2 2 Core: Brown -- Line and Blue -- Neutral 3 3 Core: Brown -- Line, Blue -- Neutral and Green/Yellow -- Ground 4 4 Core: Brown -- Line, Black -- Line, Gray -- Line /Neutral and Green/Yellow -- Ground **PC (e) Use cables and conductors for a given task** In the previous PCs you learnt about types of cables and cable color codes. This PC is developed to let you use a 3 core cable to wire a 13A socket outlet. Materials and tools: 13 A socket, pliers and screw driver. Procedure: 1. 2. 3. 4. 5. 6. 7. The checklist below will be used to assess your learning **Check List 3: Use cables and conductors for a given task** -------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------------------------------ ----- ---- No Yes No 1 Select the size of cable. 2 Identify the live, neutral, and ground terminals of the socket. 3 Identify the live, neutral, and ground cables as Brown, Blue and Green/Yellow. 4 Strip the ends of your wires. 5 Place the blue wire into the neutral terminal, brown wire into the live terminal and the green/yellow wire into the earth terminal 6 Make sure that the wires are fully inserted into the terminal and that no bare copper wire is visible. 7 Tighten the screws securely onto the wire, not the outer sheathing. Adherence to safety **Self-Assessment 1** This learning outcome (LO) has a little quiz at the end. I recommend you take this whole quiz without looking back for any of the answers. This is meant to help you determine how well you have understood this learning outcome. Now assess yourself with the questions below: 1. **Task** **Cable size** --- ----------------------------------------------- ---------------- A Lighting circuitry and switches B Ring mains, plug and socket wiring C High power ring mains, plug and socket wiring 2. +-----------------------+-----------------------+-----------------------+ | **Cable type** | **Colour code** | **Task** | +=======================+=======================+=======================+ | 2 Core | Brown | | | | | | | | Blue | | +-----------------------+-----------------------+-----------------------+ | 3 Core | Brown | | | | | | | | Blue Green/Yellow | | +-----------------------+-----------------------+-----------------------+ **References** 1. 2. 3. 4. 5.