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B. Cable Grips

When using a cable grip to pull cables, the maximum tension should not exceed the value shown in the following two tables, or the formula used in the table above.

Pulling Grips Maximum Pulling Tension (lbs)     
Type of Cable PE, XLP Single Cable Insulated Multiple Cables EPR Single Cable Insulated Multiple Cables
Unshielded, with or without Jacket 2000 2000 2000 2000
Concentric Wire URD with Jacket 10000 5000 10000 10000
Concentric Wire URD without Jacket 10000 5000 6000 3000
Taped Shielded with Jacket 10000 5000 10000 10000
Fine Wire Shielded with Jacket 10000 5000 10000 10000
LC Shielded with Jacket 8000 4000 5000 2500
Polymeric Armored Cables (See Note 3) 10000 10000
Interlock Armor with PVC Jacket 5000† 5000†
Interlock Armor with Poly Jacket 5000† 5000†
Lead Sheathed Cables See Subsequent Table

 
† Interlock Armor pulling tension using pulling grips should be limited to the lesser of the value provided above or 50% of value of Tmax calculated using “Pulling Eye” formula.

Note 1: The above tensions correspond to three cables in one grip. The stress on the cable conductor should not exceed 16,000 psi (0.013 lbs/cmil) for annealed copper conductors when using a grip.  For stranded ¾ and full hard aluminum conductors the stress should not exceed 14,000 psi (0.011 lbs/cmil) and 10,000 psi (0.008 lbs/cmil) for solid ½ to full hard aluminum conductors. The allowable conductor stress should be based on two cables sharing a load for three single conductor cables in parallel and triplexed configurations.

Note 2: The manufacturer of the cable(s) used should be contacted to determine the mechanical limitations of the cable(s).

Note 3: It is recommended that pulling grips be used during installation of Polymeric Armored Cables, due to their higher sidewall bearing pressure capabilities.

Pulling Grips Maximum Pulling Tension (psi)

Type of Cable PE, XLP Insulated EPR Insulated Paper Insulated
Single
Cable
Multiple
Cables
Single
Cable
Multiple
Cables
Single
Cable
Multiple
Cables
Lead Shielded 16000
(Note 4)
16000
(Note 4)
8000
(Note 5)
8000
(Note 5)
1500
(Note 6)
1500
(Note 6)

Note 4: The maximum pulling tension stress limit for pulling grips on lead sheathed cable with XMPLE/TRXLPE insulation is 16,000 psi of lead sheath area for a single cable as well as one grip on three cables (per AEIC CG5-2005).

Note 5: The maximum pulling tension stress limit for pulling grips on lead sheathed cable with EPR insulation is 8,000 psi of lead sheath area for a single cable as well as one grip on three cable (per AEIC CG5-2005).

Note 6: The maximum pulling tension stress limit for pulling grips on lead sheathed cable with Paper insulation is 1,500 psi of lead sheath area for a single cable as well as one grip on three cables (per IPCEA P-41-412-1958).


Sidewall Bearing Pressure (Static Conditions)

The dynamic radial pressure of cable which is pulled around a bend under pulling tension should be kept as low as possible and not exceed the following values listed in the table. To calculate these values use the following formula:

PSW = Te ÷ Br

Where:

PSW = Sidewall Bearing Pressure in pounds per foot of bend radius
Te = Pulling Tension as cable exits the bend (lbs)*
Br = Bend radius, in feet

*Note: The maximum pulling tension determined by the above formulas must be observed.


Sidewall Bearing Pressure (Dynamic Conditions)

To calculate the minimum bending radii for dynamic conditions, use the following formula:

MBR = (Te ÷ PSW) x 12

Where:

MBR = Minimum Bending Radius (in)
Te = Pulling Tension as cable exits the bend (lbs)*
PSW = Maximum Sidewall Bearing Pressure in pounds per foot of bend radius from following table

*Note: The maximum pulling tension determined by the above formulas must be observed.

Sidewall Bearing Pressure (lbs/ft of bend radius)*

Type of Cable PE, XLP
Insulated
EPR
Insulated
Unshielded, without Jacket 1200 500
Unshielded, with Jacket 1200 1000
Interlock Armor with PVC Jacket Single Conductor & Three Conductor having round core (100% fillers) 800 800
Interlock Armor with Poly Jacket Single Conductor & Three Conductor having round core (100% fillers) 1000 1000
Concentric Wire URD, without Jacket 1200† 1000†
Concentric Wire, Encapsulating Jacket 2000 2000
Concentric Wire, with Sleeved Jacket 1500 1500
LC Shielded with Jacket 1500 1500
Taped Shielded with Jacket 1500 1500
Fine Wire Shielded with Jacket 1500 1500
Teck-90 Cable, Single Conductor & Three Conductor having round core (100% fillers) 800 800
Teck-90 Cable, Three Conductor with minimal or no fillers 350 350
Lead Sheathed (Solid Dielectric) 2000** 2000**
Polymeric Armored Cables Air Bag® 2400
AirGuard® 3000
Lead Sheath (PILC) 400

† Value shown corresponds to a single conductor cable pull. Maximum Sidewall Bearing Pressure limits of 750 and 200 lbs. per foot, respectively, are recommended for a three-conductor pull.

* For a pulling eye/pulling grip, the maximum pulling tension must be observed in addition to the maximum sidewall bearing pressure limit.

** These values are based on the cross-sectional area of one lead sheath.

Note 1: It is recommended that the manufacturer of the cable(s) in question be contacted concerning the mechanical limitations of the cable.