A method of controlling access to data (DA, DB) relative to at least one electrical installation (12A, 12B), exchanged between a respective management unit (14A, 14B) of each electrical installation and a relay platform, the relay platform belonging to a global communication network and each management unit (14A, 14B) belonging to a respective local communication network (R1A, R1B), each management unit (14A, 14B) having a respective first identifier, each management unit (14A, 14B) being connected to the global communication network by a respective communication gateway (16A, 16B) having a second identifier on the global communication network, the method including the following steps: - exchanging at least one frame (TA, TB) between each management unit (14A, 14B) and the relay platform, each frame (TA, TB) including the data (DA, DB) and the second identifier of the communication gateway by which the frame (TA, TB) passes, - obtaining, for each exchanged frame (TA, TB), the first identifier of the management unit (14A, 14B) exchanging the frame, - receiving, by the relay platform, a request to access the data (DA, DB) exchanged with the one of the management units (14A, 14B), the request coming from a communication terminal and including an access parameter depending on the first identifier of the management unit (14A, 14B) and a third identifier, on the global network, of an element belonging to the global network and being at the origin of the transmission of the request on the global network, - determining the first identifier on which the access parameter depends, - comparing the third identifier with the second identifier comprised in the or at least one of the frames (TA, TB) exchanged by the management unit (14A, 14B) having the determined first identifier, - authorizing access, for the communication terminal, to the data (DA, DB) included in each frame exchanged by the management unit (14A, 14B) having the determined first identifier if, during the comparison step, the second and third identifiers are identical, the method comprising, for each management unit, the following step: - launching a respective time counter (CTA, CTB) from a respective reference moment, and, during the authorization step, the access to the data (DA, DB) included in each frame exchanged by the management unit (14A, 14B) having the determined first identifier is also authorized for the communication terminal, if the value of the time counter (CTA, CTB) of the management unit (14A, 14B) having the determined first identifier is less than or equal to a predetermined maximum value. - exchanging at least one frame (TA, TB) between each management unit (14A, 14B) and the relay platform, each frame (TA, TB) including the data (DA, DB) and the second identifier of the communication gateway by which the frame (TA, TB) passes, - obtaining, for each exchanged frame (TA, TB), the first identifier of the management unit (14A, 14B) exchanging the frame, - receiving, by the relay platform, a request to access the data (DA, DB) exchanged with the one of the management units (14A, 14B), the request coming from a communication terminal and including an access parameter depending on the first identifier of the management unit (14A, 14B) and a third identifier, on the global network, of an element belonging to the global network and being at the origin of the transmission of the request on the global network, - determining the first identifier on which the access parameter depends, - comparing the third identifier with the second identifier comprised in the or at least one of the frames (TA, TB) exchanged by the management unit (14A, 14B) having the determined first identifier, - authorizing access, for the communication terminal, to the data (DA, DB) included in each frame exchanged by the management unit (14A, 14B) having the determined first identifier if, during the comparison step, the second and third identifiers are identical, - launching a respective time counter (CTA, CTB) from a respective reference moment,