A system of protection from unauthorized access to a valve of a fuel-gas tank, comprising: a valve comprising an inlet portion configured for enabling execution of operations of filling of the tank; and blocking means that co-operate with said valve for blocking, between a closing position and an opening position, access to said valve; said blocking means being operated between the closing and opening positions by actuator means supplied with electrical energy, said system comprising a terminal in the form of a wireless terminal configured for governing said actuator means, said wireless terminal comprising means for sending a charging signal that includes a data signal portion and a supply portion, which carries energy via electromagnetic induction, in particular a WPC (Wireless Power Consortium) signal; said blocking means being configured for receiving electrical energy from said supply portion of said charging signal in order to operate said actuator means, said blocking means further comprising control means in the form of a control module that enables operation of said actuator means according to said data signal portion of the charging signal exchanged with corresponding control means in the form of a control module of the wireless terminal, said blocking means in said closing position being blocked on the valve preventing access to the inlet portion characterized in that said blocking means comprise sensor means for detecting the position of the actuator means and sensor means for detecting the position of the valve, and moreover the control module of the blocking means comprises a module configured for comparing the information of said two sensor means (31, 20a). a valve comprising an inlet portion configured for enabling execution of operations of filling of the tank; and blocking means that co-operate with said valve for blocking, between a closing position and an opening position, access to said valve; said blocking means being operated between the closing and opening positions by actuator means supplied with electrical energy, said system comprising a terminal in the form of a wireless terminal configured for governing said actuator means, said wireless terminal comprising means for sending a charging signal that includes a data signal portion and a supply portion, which carries energy via electromagnetic induction, in particular a WPC (Wireless Power Consortium) signal; said blocking means being configured for receiving electrical energy from said supply portion of said charging signal in order to operate said actuator means, said blocking means further comprising control means in the form of a control module that enables operation of said actuator means according to said data signal portion of the charging signal exchanged with corresponding control means in the form of a control module of the wireless terminal, said blocking means in said closing position being blocked on the valve preventing access to the inlet portion characterized in that said blocking means comprise sensor means for detecting the position of the actuator means and sensor means for detecting the position of the valve, and moreover the control module of the blocking means comprises a module configured for comparing the information of said two sensor means (31, 20a).