Ordinary bolts shall meet the following requirements as permanent connecting bolts:
1. For general bolted connections, flat washers should be placed under the bolt heads and nuts to increase the bearing area.
2. Flat washers should be placed on the bolt head and nut side respectively. The flat washers placed on the bolt head side should not be more than two, and the flat washers placed on the nut side should not be more than one.
3. For the bolts and anchor bolts that are required to be loosened, the nuts or spring washers of the anti-loose device should be used. The spring washers must be placed on the side of the nut.
4. For bolted connections that bear dynamic loads or important parts, spring washers should be placed as required by the design. Spring washers must be placed on one side of the nut.
5. For the I-beam and channel steel, the inclined washer should be used when the inclined surface is connected, so that the bearing surface of the nut and the bolt head is perpendicular to the screw.
Bolt use position classification requirements
According to the position and function of the distribution line bolts, the bolts can be divided into three types: electrical connection type, electrical equipment fixed type and iron attachment fixed type. The following details:
1. Electrical connection: Outdoor primary wiring should be connected by hot-dip galvanized bolts. The bolts used should have flat washers and spring washers. After the bolts are tightened, the bolts should be exposed with 2~3 buckles. One bolt is equipped with two flat washers, a spring washer, and a nut. A flat washer is placed on the side of the bolt head during installation, and a flat washer and a spring washer are placed on the nut side, wherein the spring washer is placed against the nut.
2. Electrical equipment fixing type: transformer, distribution box base and iron attachment connection. When connecting with channel steel inclined bolts, one bolt is equipped with one nut, one inclined washer (for the slope side of the channel) and a flat washer (planar) 2 side use). When bolted with a channel bolt, one bolt is fitted with two flat washers, a spring washer, and a nut. A flat washer is placed on the side of the bolt head during installation, and a flat washer and a spring washer are placed on the nut side, wherein the spring washer is placed against the nut. For the connection of the isolating switch, the drop fuse, the arrester and the iron accessory, in principle, use the mounting bolts supplied by the equipment manufacturer.
3. Iron attachment type: When the iron attachment bolt hole is a round hole, one bolt is equipped with one nut and two flat washers. When the iron attachment bolt hole is a long hole, one bolt is equipped with one nut and two square washers. Install a flat washer (square washer) on the bolt head side and the nut side during installation. When the iron attachment is connected with a stud, each end of the bolt is provided with a nut and a flat washer (square washer). For bolted joints on the inclined faces of channel and I-beam flanges, use inclined washers as much as possible so that the bearing surfaces of the nut and bolt head are perpendicular to the screw.
Bolting requirements
1. For the three-dimensional structure: the horizontal direction is from the inside to the outside; the vertical direction is from the bottom to the top.
2. For the plane structure: in the direction of the line, the double-sided members are from the inside to the outside, the single-sided members are penetrated by the power transmission side or in a uniform direction; the horizontal line direction, the sides are from the inside to the outside, and the middle is from the left to the right (facing the power Side) or in a uniform direction; vertical direction, from bottom to top.
3. Transformer gantry plane structure: take the high and low voltage terminals of the transformer as the reference direction, and wear from the low voltage terminal end to the high voltage terminal; take the transformer and the pole as the reference direction, and wear from the transformer side to the pole side (from the inside out wear).
Bolt tightening requirements
The connecting bolts shall be tightened one by one, and the tightening torque of the bolts shall not be less than that specified in Table 4. If the screw and nut thread are found to have slippery teeth or the edges of the nut are worn so that the wrench is slippery, the bolt and nut should be replaced.
Table 4: Bolt tightening torque standards
Bolt assembly
1. Visually check the bolts, nuts or wire holes of the connected parts before assembly. There should be no bumps or scratches, which conforms to the standards quoted in the drawings or this specification.
2. Do not scratch the threaded portion of the bolt during assembly.
3. The head of the bolt and the washer on the end face of the nut should be in uniform contact with the plane of the part to be fastened. It should not be inclined, nor should it be touched by a hammer to make the two planes contact. The screw should be free from bending deformation.
4. The connected parts should be evenly pressed, closely attached to each other, and the connection is firm.
5. It is forbidden to use an unsuitable wrench when tightening bolts and nuts.
6. When assembling bolts and screws, you should screw in more than 2 to 3 pitches by hand, and then tighten with a wrench or power tool.
7. When assembling bolts and nuts, pay attention to protect the paint film, plating layer and bolt and nut head of the jointed parts, and do not damage them.
8. After the nut is tightened, the bolt head should expose 2 to 3 pitches of the nut end face. The nut and the washer face the connected body with the reverse side (the side marked with the nut is the front side and the side of the smooth side of the washer is the front side).
9. After the bolt is tightened, the paint mark is generally marked with red paint at the contact point of the bolt and the nut. Colors can vary depending on where you use them, but the colors must be clearly differentiated.