Stringing blocks are used in conjunction with pulling and tensioning equipment on the job site.
The style of the block depends on the size and type of the wire being pulled. Improper block selection will damage the conductor.
Stringing blocks are available with polished aluminum sheaves or urethane-lined sheaves. Ductile iron sheaves are available with smaller 7” blocks for installation of shield wire.
Following is an overview of some broad stringing block categories:
Universal Blocks
Custom Truck’s versatile universal blocks have a 7” sheave with a 2500 lb. safe working load or our new 11” sheave with a 4,000 lb. safe working load. The 7” block is available with an optional grounding stud and one of three opening options: spring-latch, twist latch, or detent pin. Universal blocks can be suspended or mounted on a cross-arm.
Full Frame Blocks
Full frame blocks have various sheave sizes ranging from 16” to 42”. Their large throats are designed for the safe, smooth passage of swivels, Kellems grips, and splices. These blocks are also available with a spring-loaded grounding arm and roller. Sheaves available for this product are polished aluminum and urethane lined.
Helicopter Blocks
Helicopter blocks earn their name because they are used in conjunction with a helicopter. However, due to their lightweight and functionality, linemen use them for conventional work as well. Sheave sizes range from 10” to 46”. Our helicopter blocks also accommodate the safe, smooth passage of swivels, Kellems grips, and splices. Additionally, this block is available with a spring-loaded grounding arm and roller. The helicopter blocks can be ordered with a bolt-on stand that allows for angle pullbacks. The polished aluminum or urethane-lined sheaves are available for helicopter blocks as well. Fly arms are always included at no extra cost.
8” Distribution Bundle Blocks
Our 8” distribution bundle blocks have three aluminum sheaves that can pull two or three conductors. This block can either be suspended or mounted on a cross arm with its integrated bracket.
Bundle Blocks
Our transmission bundle blocks, have sheave diameters ranging from 22” to 42”. They are urethane-lined and can be customized to fit several applications. Accessories include “Pacman” helicopter attachment, header bar, rope guides, and grounding rollers.
Custom Truck offers a variety of stringing blocks including but not limited to radius blocks, tandem blocks, hold-down blocks, uplift blocks as well as a full assortment of accessories.
Reach out to us with questions about our stringing block assortment if you are interested in renting or purchasing for upcoming jobs.
