Maximum Allowable Pulling Tension with a Basket Weave Grip

The equations below calculate the maximum pulling tension if a basket-weave grip is used.

PILC Cable:

(3/C Cables)

ALS = p t (d - t)

Tmax = 2000 x ALS

Where:

ALS = Area of lead sheath (in)

Tmax = Maximum pulling tension (lb)

t = Thickness of lead sheath (in)

d = Outside diameter of lead sheath (in)

Solid Dielectric Cables:

Tmax = 2000 lb (600V, each)

Tmax = 4000 lb (Primary, each)

-- OR --

Tmax from the Maximum Pulling Tension Using Pulling Eye table.

Compare; choose the lower Tmax

Tension on a Single Cable

On a single cable pull, the basket-weave grip grips the entire circumference of the cable equally and transfers the force to the center of the cable. The maximim tension can be exerted on one cable.

Tension on Multiple Cables

On multiple cable pulls (more than one cable in a single grip) the entire grip does not tighten over all the cable as effectively as it does on a single cable. Therefore, there is an unequal distribution of the force on the cables. The equations for determining the maximum pulling tension for multiple cable pulls are:

Tension Distributed on Cables

If multiple cables pulls are:

Follow table number:

Same size, parallel lay (not triplex or quadruplex)

1

Different sizes caused by including a separate neutral of a smaller size than the phase conductor

2

Triplex or quadruplex

3

Tension on Same Size Cables, Parallel Lay

Number of Cables

Equation

2

TTmax = Tmax x 1.5

3

TTmax = Tmax x 2.0

4

TTmax = Tmax x 3.0

Where:

TTmax = Total maximum pulling tension

Tmax = Maximum pulling tension/phase conductor

Tension on Multiple Cables with Separate Neutrals

If:

And:

Then Use Equation:

In a three cable pull where the neutral is the third cable

The neutral is the same size or one stock size less than the phase conductor

TTmax = Tmax x 2.0

The neutral is more than one stock size less than the phase conductor or bare

TTmax = Tmax x 1.5

In a four cable pull where the neutral is the fourth cable

The neutral is the same size or one stock size less than the phase conductor

TTmax = Tmax x 3.0

The neutral is more than one stock size less than the phase conductor or bare

TTmax = Tmax x 2.0

Tension on Triplex and Quadruplex Cables

Number of Cables

Equation

Triplex

TTmax = (Tmax x 2.0) + NTmax

Quadruplex

TTmax = Tmax x 3.0) + NTmax

Where:

TTmax = Total maximum pulling tension

Tmax = Maximum pulling tension/phase conductor

NTmax = Maximum pulling tension/neutral conductor

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