Overvoltage protection assembly comprising at least: - a modular circuit breaker comprising at least a first phase line comprising at least a first phase connection terminal and a second phase connection terminal, a first neutral line comprising at least a first neutral connection terminal and a second neutral connection terminal, and a first housing, - a modular surge arrester comprising at least a second phase line comprising at least a third phase connection terminal, a second neutral line comprising at least a third neutral connection terminal, a first earth line comprising at least a first earth connection terminal, and a second housing, - electrical and mechanical connection means comprising at least a first phase electrical conductor and a second neutral electrical conductor, said protection assembly being characterized: in that it further comprises a connection module comprising the electrical and mechanical connection means comprising the first phase electrical conductor configured to be connected on the one hand to the second phase connection terminal of the modular circuit breaker and on the other hand to the third phase connection terminal of the modular surge arrester, the second neutral electrical conductor configured to be connected on the one hand to the second neutral connection terminal of the modular circuit breaker and to be connected on the other hand to the third neutral connection terminal of the modular surge arrester, and a second earth connection terminal comprising an input intended to be connected to the first earth connection terminal of the modular surge arrester and an output, and a third housing, in that the modular circuit breaker, the modular surge arrester and the connection module form a first entity delimited by the first housing, a second entity delimited by the second housing, and a third entity delimited by the third housing, respectively. - a modular circuit breaker comprising at least a first phase line comprising at least a first phase connection terminal and a second phase connection terminal, a first neutral line comprising at least a first neutral connection terminal and a second neutral connection terminal, and a first housing, - a modular surge arrester comprising at least a second phase line comprising at least a third phase connection terminal, a second neutral line comprising at least a third neutral connection terminal, a first earth line comprising at least a first earth connection terminal, and a second housing, - electrical and mechanical connection means comprising at least a first phase electrical conductor and a second neutral electrical conductor, said protection assembly being characterized: in that it further comprises a connection module comprising the electrical and mechanical connection means comprising the first phase electrical conductor configured to be connected on the one hand to the second phase connection terminal of the modular circuit breaker and on the other hand to the third phase connection terminal of the modular surge arrester, the second neutral electrical conductor configured to be connected on the one hand to the second neutral connection terminal of the modular circuit breaker and to be connected on the other hand to the third neutral connection terminal of the modular surge arrester, and a second earth connection terminal comprising an input intended to be connected to the first earth connection terminal of the modular surge arrester and an output, and a third housing, in that the modular circuit breaker, the modular surge arrester and the connection module form a first entity delimited by the first housing, a second entity delimited by the second housing, and a third entity delimited by the third housing, respectively.