Post-Type Insulators The post insulators are used on distribution, substation, and transmission lines and are installed on

Figure 4-22.- A two-layer porcelain pin insulator.

Figure 4-23.- Steel clamp pin. wood, concrete, and steel poles. The line-post insulators are manufactured for vertical or horizontal mounting. The line-post insulators are usually manufactured as one-piece solid porcelain units or fiber glass epoxy-covered rods with metal end fittings and

rubber weather sheds. The insulators are fabricated with a mounting base for curved or flat surfaces, and the top is designed for tying the conductor to the insulator or fitted with a clamp designed to hold the conductor. Line-post insulators designed for vertical mounting are mounted on crossarms. This type of construction is often used for long span rural distribution circuits.

Figure 4-25 showsdistribution circuits constructed with porcelain horizontal line-post insulators. This armless construction, using post insulators, permits the construction of subtransmission and transmission lines on narrow rights-of-way and along city streets.

Figure 4-24.- Steel pin

Figure 4-25.- Post insulators for armless construction. Suspension Insulator In

figure 4-26 you see the common suspension insulator. The suspension insulator, as its name implies, is suspended from the crossarm and has the line conductor fastened to the lower end. It is designed for ease of linking units together. Linking of these insulators gives you the versatility of ordering one insulator to be used with varying voltages.