Lightning and Surge Protection for Weighbridges

Installed in open areas and built from a large steel surface with long cable runs, weighbridges are easily affected by lightning and mains-borne overvoltages. A weighbridge that stops weighing completely after a stormy night is one of the most common cases we encounter in our service records.

How Does Damage Occur?

Even if lightning does not strike the weighbridge directly, the voltage induced by a strike nearby can enter through load cell cables, the power line or the data line and damage the load cells, junction box and indicator.

Recommended Measures

• Equipotential bonding: Connecting the platform, load cells and weighbridge building to a common, low-resistance grounding system
• Earth bonding straps: Copper braided connections that carry current across each load cell
• Surge arresters and protection modules: Overvoltage protectors on power, load cell and data lines
• Cable protection: Routing cables inside protective conduit and along the shortest possible path
• Uninterruptible power supply: A quality UPS for the indicator and computer

Grounding resistance may change over time; we recommend measuring it during maintenance visits and recording the results.