When stripping wire with any of the tools mentioned, observe the following precautions:

• Do not attempt to use a hot-blade stripper on wiring with glass braid or asbestos insulation. These insulators are highly heat resistant.
• When using the hot-blade stripper, make sure the blades are clean. Clean the blades with a brass wire brush as necessary.
• Make sure all stripping blades are sharp and free from nicks, dents, and so forth.
• When using any type of wire stripper, hold the wire perpendicular to the cutting blades.
• Make sure the insulation is clean-cut with no frayed or ragged edges; trim if necessary.
• Make sure all insulation is removed from the stripped area. Some types of wire are supplied with a transparent layer between the conductor and the primary insulation. If this is present, remove it.
• When the hand strippers are used to remove lengths of insulation longer than 3/4 inch, the stripping procedure must be done in two or more operations.
• The strippers will only strip about 3/4 inch at one time.
• Retwist strands by hand, if necessary, to restore the natural lay and tightness of the strands.
• Strip aluminum wires with a knife as described earlier. Aluminum wire should be stripped very carefully. Care should be taken not to nick the aluminum wire as the strands break very easily when nicked.

Q.1 What are the basic requirements for any splice or terminal connection?
Q.2 What is the preferred method for stripping wire?
Q.3 What stripping tool would NOT be used to strip glass braid insulation?
Q.4 What tool should be used to strip aluminum wire?

TYPES OF SPLICES

There are six commonly used types of splices. Each has advantages and disadvantages for use. Each splice will be discussed in the following section.

Western Union Splice

The Western Union splice joins small, solid conductors. Figure 2-5 shows the steps in making a Western Union splice.

Figure 2-5. - Western Union splice.

Prepare the wires for splicing.

• Enough insulation is removed to make the splice.
• The conductor is cleaned.
• Bring the wires to a crossed position and make a long twist or bend in each wire.
• Wrap one end of the wire and then the other end four or five times around the straight portion of each wire.
• Press the ends of the wires down as close as possible to the straight portion of the wire. This prevents the sharp ends from puncturing the tape covering that is wrapped over the splice. The various types of tape and their uses are discussed later in this chapter.

Staggering Splices

Joining small multiconductor cables often presents a problem. Each conductor must be spliced and taped. If the splices are directly opposite each other, the overall size of the joint becomes large and bulky. A smoother and less bulky joint can be made by staggering the splices.

Figure 2-6 shows how a two-conductor cable is joined to a similar size cable by using a Western Union splice and by staggering the splices. Care should be taken to ensure that a short wire from one side of the cable is spliced to a long wire, from the other side of the cable. The sharp ends are then clamped firmly down on the conductor.

The figure shows a Western Union splice, but other types of splices work just as well.

Figure 2-6. - Staggering splices.

Rattail Joint

A splice that is used in a junction box and for connecting branch circuits is the rattail joint (figure 2-7).

Figure 2-7. - Rattail joint.

Wiring that is installed in buildings is usually placed inside long lengths of steel or aluminum pipe called a conduit. Whenever branch or multiple circuits are needed, junction boxes are used to join the conduit.