The installation of crossarms for power distribution lines is a delicate task requiring consideration of multiple factors.
First, the crossarm's installation position should be opposite to the power supply side. That is, the crossarm for straight poles should be installed on the load side, while the crossarms for corner poles, branch poles, terminal poles, and poles with unbalanced conductor tension should be installed on the guy wire side.
Furthermore, the installation of crossarms must meet specific distance requirements.
For example, when the conductors are arranged horizontally, the distance from the horizontal plane of the upper crossarm to the top of the pole should be no less than 300 mm; while when the conductors are arranged in a triangular pattern, the distance from the upper crossarm to the top of the pole is generally 500 mm.
For single crossarm installations, regulations stipulate that straight poles should be installed on the power receiving side, while corner poles, T-shaped poles, and terminal poles should be installed on the guy wire side.
During installation, it is also necessary to ensure that the crossarm is level and straight, with an vertical tilt not exceeding 20 mm.
Meanwhile, there are specific rules for the direction of bolt insertion: bolts should be inserted from the power supply side along the line direction, from left to right towards the power receiving side across the line, and from bottom to top vertically.
Regarding bolt configuration, the exposed length of the bolt thread must be at least two thread pitches, and double nuts must expose at least one thread pitch. Bolts under tension should have double nuts, and long holes must have double washers, no more than two at each end. Wire must not be wrapped around the bolt to replace washers.
Single nuts should have a spring ring and a flat washer, and must be tightened securely.
In general, the installation of crossarms for power distribution lines requires meticulous operation based on actual conditions and regulations to ensure correct installation position, appropriate spacing, and complete and compliant bolt configuration.