This structure is a type of distribution transformer, designed to replace the overhead pole-mounted units used in older neighborhoods and is enclosed in a robust, tamper-resistant metal housing, often painted green or gray. The large, green metal box sitting low to the ground in a yard is a common sight in modern suburban and residential neighborhoods utilizing underground power distribution. These enclosures often generate curiosity because they are securely locked, marked with danger signs, and located on what. As the name implies, an electrical transformer box is a metal unit that contains a piece of electrical equipment called a transformer. These diagrams provide a visual representation of the connections and components that make up the utility pole, such as transformers, meters. Most likely a Telecom box that houses phone lines, internet fiber etc, I agree with Thomas, underground telephone and or cable lines most likely leading to that box next to the gas meter on the side of the house. Haven't seen one of these green boxes before. On top of the pole and usually carries 12,000 volts of electricity from a substation.
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