Dimensions of anti-bolts in distribution boxes

Anti-bolts in distribution boxes are typically high-tensile, concealed, or stainless steel bolts designed to prevent unauthorized access, with dimensions varying according to box size and mounting requirements.

General Specifications

Anti-bolts are used to secure the cover of a distribution box to its base, ensuring tamper resistance and safety. They are often concealed behind the door or collar of the box to prevent direct access from outside . Common features include:

• Material: Stainless steel or high-tensile steel to resist corrosion, rust, and tampering .
• Mounting: Usually fitted with nuts on the inside of the box or with adjustable studs for easy removal of the pan assembly .
• Quantity: Typically, three or more anti-bolts are used for small LT distribution boxes, while larger boxes may have four or more, depending on the cover size and security requirements .

Typical Dimensions

While exact dimensions vary by manufacturer and box size, standard anti-bolts for LT distribution boxes generally follow these ranges:

• Diameter: 6 mm to 12 mm (M6 to M12 metric bolts are common)
• Length: 20 mm to 50 mm, depending on the thickness of the box wall and cover
• Thread Type: Metric coarse threads (M6, M8, M10) are standard for easy assembly and secure fastening
• Head Type: Often hex or tamper-proof heads, sometimes with concealed nuts inside the box For larger distribution boxes or transformer-mounted boxes, bolts may be hot-dip galvanized and longer to accommodate mounting on plinths or MS channels .

Installation Considerations

• Anti-bolts should be tightened securely but not over-torqued to avoid cracking the box material, especially for thermosetting plastic (SMC) boxes .
• The cover should rest on the collar of the base, with bolts positioned so that external access is not possible .
• For metal boxes, high-tensile screws are used to secure detachable covers, often in combination with neoprene gaskets for weatherproofing .

Summary

Anti-bolts in distribution boxes are concealed, corrosion-resistant fasteners designed for security and durability. While exact dimensions depend on the box type and manufacturer, M6–M12 bolts with lengths of 20–50 mm are typical for LT distribution boxes, with larger boxes requiring longer or more robust bolts. Proper installation ensures both tamper resistance and safe operation .