How to choose the right dead end clamp？
The selection of the dead end clamp is mainly determined according to the different conditions of the power line conductors.
There are two common situations. Malon Dead End Grip Manufacturers will explain to you.
1. Selection of line strain clamps when LGJ and LJ conductors are used
When using LGJ or LJ wire, since the dead end clamp is clamped on the outer diameter of the wire when used, the model of the
dead end clamp used should be selected according to the outer diameter of the wire. For example, the LGJ-185/30 wire is used
in the power line. After calculation, it can be found that its outer diameter is 18.88mm. From the above table, it is known that
the dead end clamp should be NLL-4, NLL-5 or NLD-4.
It should be noted here that the outer diameter of LGJ wire is calculated from the cross-section of aluminum wire 185mm and the cross-section of steel core 30mm. It is not simply calculated by the cross-section of aluminum wire 185mm. LGJ wires of the same specification have different steel core cross-sections and wire outer diameters, so thedead end clamp used for LGJ wires of the same specification are not necessarily the same. If it is an LJ wire,since it does not have a steel core, the cross-section of the aluminum stranded wire can be used to calculate the outer diameter of the wire.
In addition, since the dead end clamp is clamped on the outer diameter of the wire, we require that the outer layer of LGJ or LJ wire be covered with aluminum tape during construction to prevent damage to the wire during crimping.
2. Selection of line dead end clamp when insulated wire is used
In densely populated, wooded, and polluted areas, we are increasingly using insulated wires instead of bare wires. Compared with bare wires, it has the advantages of higher safety and reliability, lower wire loss, and less wire corrosion. When using insulated wires, we need to pay attention to the fact that the dead end clamp is clamped on the outer diameter of the “wire” instead of the outer diameter of the “conductor” when used, so it should be based on the outer diameter of the wire instead of the outer diameter of the “conductor”. The outer diameter of the conductor is used to select the type of dead end clamp used. For example, JKLGYJ-150/8 steel core reinforced cross-linked polyethylene insulated aerial cable is used in the power line. It is calculated that its conductor outer diameter is 15.30mm, plus its insulation thickness of 3.4mm and conductor shielding thickness 0.5mm, it can be seen that the outer diameter of its conductor is 23.1 mm. Check the above table to know that the strain clamp that should be used is NLL-5. If we select the equipment clamp according to the conductor outer diameter 15.30mm at this time, the selectedequipment clamp cannot be used.
In addition, we must tighten the screws evenly when installing the dead end clamp. It is required that the wire stress does not increase at the contact surface between the wire and the metal after installation, so as to prevent the wire from being damaged and caused by breeze vibration or other wire vibration. Ensure that the grip strength of the dead end clamp/dead end grip on the wire is not less than 95% of the wire breaking force.