Lighting strikes produced during storms it is a risk factor that can damage the electronic equipment as load cells and weighing indicators, especially those that has components located outdoor as weighbridges and silos. 1. Effects of a lighting strike These can affect weighing instruments mainly in two ways: 1.1 Direct Impact Direct Impact can destroy any the component of a scale due to the high energy locally concentrated. 1.2 Indirect Impact Indirect Impact can induce currents at some hundred meters around the site affecting the weighbridge circuits. These currents are produced by the induction of an electromagnetic pulse and by a differential of potential created in the different points of the earth. 2. Protection Systems By using some principles of protection and specific protection devices these risks can be minimized: 2.1 Protection against Direct Impact Outdoor systems can be protected against direct impact of lighting strikes by the use of an adequate earthing mast for safely conduct the surge to the earth. 2.2 Protections against Indirect Impact Protection against Indirect Impact is performed by the use of several steps as: 2.2.1. All metallic structures and devices must be connected to common grounding point for potential equalization (Figure 1):
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