Electricity:
Making a Lamp by Wiring a Light Socket and Plug.


The purpose of this section is to assemble a basic lamp. This will provide a familiarity with some basic household electrical hardware. While the lamp is a fairly simple electrical device, all of the assembly steps must be executed in the proper fashion. Failure to do so may lead to a hazardous situation.

Collection of graphics used

IMPORTANT
Do not attempt to plug in your lamp at anytime during this exercise.
It must first be checked by an instructor.
The lamp is to be plugged-in and tested only by an instructor or TA and only at the designated testing location.
 
 

Wiring the plug.

1. Locate the plug.

2. Unscrew the two screws next to the prongs that hold the plug together. Do not lose the screws. Pull the plug apart and set the components aside.

3. Locate the brown line cord (this type of wire is also called zip cord or lamp cord).

4. On one end, separate the wire as shown in Figure 1. Use the orange razor knife to start the split. Be careful the knife is sharp. Always cut away from yourself. Use the cardboard as a cutting surface. Do not cut directly on the table. Separate about 2 inches of wire.

5. Tie the underwriter’s knot in the wire as shown in Figure 2 and on the chalk board in the front of the room.

6. After tying the knot, use the wire cutters to cut the wires so about 1 inch is left after the knot.

7. Use the red wire strippers to remove 1/2 to 3/4 inch length of insulation from each of the two wires on one end of the cord. See Figure 3. There should be an extra piece of wire in the tool box on which you can practice using the wire strippers.

8. Put the wire through the plug housing as shown in Figure 4.

9. Twist each wire so the wire strands are tightly packed (as in Figure 3). It is important to twist all of the fine strands into a tightly packed bundle. Loose wires can cause a short circuit.

10. Using the pliers, bend a small loop in the wire (refer to Figure 4). It is preferable to use pliers rather than your fingers. Using pliers it is possible to make a neat loop.

11. Loosen the screws on the prongs of the plug. Continue turning them out until they stop but do not force them all of the way out.

12. Put the hook of wire around the screw. Put the wire on so the hook faces in a clockwise direction. In this way tightening the screw also tightens the loop. Tighten screw to secure the wire. This step is illustrated in Figure 5.

13. Make sure there are not any loose strands. If there are loose strands, remove wire, twist strands together and reconnect.

14a. Attach the other wire to the other prong as above.

DO NOT reassemble the plug yet! Have the plug checked and obtain initials below.

14b. Reassemble plug. To do this, push the prongs into the plug housing (as shown in Figure 6). The wire should fit neatly into the plug housing. Secure the housing by using the two small screws that you removed earlier.
 

Wiring the Lamp Socket

15. Locate lamp socket. Open socket by pressing and pulling on upper part where it is marked "Press." Identify the parts as shown in Figure 7.

16. Separate 2 1/2 inches of cord on end and put through center tube and base as shown in Figure 8.

17. Tie the underwriters knot. This is illustrated in Figure 7 or on the chalk board in the front of the room. Look closely at Figure 7, make sure the wire goes through the base plate BEFORE you tie the knot.

18. Strip off the insulation from 1/2 to 3/4 inch from the end of each wire. Twist strands of each wire into a tight bundle. Use the pliers to form a half-loop in each wire.

19. Loosen the terminal screws on the lamp socket. Do not force the screws all of the way out.

20. Wrap one wire around each terminal screw in clockwise direction and tighten screws. This is shown in Figure 7.

21. Make sure there are not any loose strands. If there are loose strands, remove wire, twist strands together and reconnect.

22. Before final assembly have lamp socket checked and obtain initials below.

23. Reassemble lamp socket. The wire should fit neatly into the bottom of the socket.

24. Once lamp has been checked and assembled, bring to testing station to be checked.

Do not plug it in yourself.

Once your working lamp has been checked, disassemble the components.

 General Aspects of Electricity
 Parts List
 Tools

 Additional Information for Instructors
 How It Works
 Laboratory Questions to Answer

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© 2001 John J. Krupczak, Jr.
All rights reserved. Reproduction in whole or in part in any form or medium without express written permission of the author is prohibited.