Safety of people in cities
The photo shows a concrete underground well. It houses cable joints for 110 kV single-core cables. There are 6 joints for 6 single-core cables, which means that there is a three-phase double-circuit cable line.
A fault (short-circuit) occurred in one of joints due to poor-quality installation, which led to an explosive increase in pressure in the well. As a result, the cast-iron cover of the well was thrown several meters to the side. A green tree located near the well was also burned. By a lucky chance, in a particular case, none of members of public were injured in this occasion. However, several cases with cable wells are already known when people received fractures due to a hit of a well сover or received burns of their limbs due to flames.
What is the danger of placing cable joints in such wells? There are risks of injury to members of public due to:
✅ being hit by a heavy well cover;
✅ being burned by flames that burst out of the well.
In addition, it is especially dangerous for the personnel of an electric grid company. If somebody was inside the well when the cable joint was damaged there, then he would get serious injuries up to fatal. What recommendations can be given to grid companies? It is recommended to bury the cable joints into the ground, and not to place them in any wells!
1️⃣ RECOMMENDATIONS to grid companies:
If cable joints are still planned to be placed in wells, then please:
✅ Equip wells away from pedestrian zones.
✅ Use measures to prevent the well cover from flying off (for example, well covers should be made on hinges so that they “open” in the event of an increase in pressure inside the well).
✅ Avoid personnel entering into the well if the cable lines are in operation.
2️⃣RECOMMENDATIONS to members of public:
Please, be aware of any well covers in the city and never step on them (you never know what is inside the well). This rule is not a guarantee of your safety, but some reduction in the risk of injury.