A fuse system for a munitions projectile , the system comprising: a first electro-optic transmitter ; a first electro-optic receiver ; the first electro-optic transmitter being arranged to receive first electrical power , and to use that received first electrical power to transmit a first optical signal to the first electro-optic receiver; the first electro-optic receiver being arranged to receive the first optical signal, and to use that first received optical signal to transmit electrical power to an element of the fuse system connected to the first electro-optic receiver; the fuse system further comprising a second electro-optic transmitter ; the second electro-optic transmitter being arranged to receive second electrical power , and to use that received second electrical power to transmit a second optical signal to the first electro-optic receiver; the first electro-optic receiver being arranged to receive the second optical signal, and to use that received second optical signal to transmit electrical power to the element of the fuse system connected to the first electro-optic receiver; wherein the second electro-optic transmitter is arranged to receive first electrical power from a power source of the fuse system, wherein the first electro-optic transmitter is arranged to receive second electrical power from a power source external to the fuse system; wherein the element is only able to receive power derived from the power source external to the fuse system via the first optical signal sent via the first electro-optic transmitter and first electro-optic receiver; and wherein the element is only able to receive power derived from the power source of the fuse system via the second optical signal sent via the second electro-optic transmitter and first electro-optic receiver. a first electro-optic transmitter ; a first electro-optic receiver ; the first electro-optic transmitter being arranged to receive first electrical power , and to use that received first electrical power to transmit a first optical signal to the first electro-optic receiver; the first electro-optic receiver being arranged to receive the first optical signal, and to use that first received optical signal to transmit electrical power to an element of the fuse system connected to the first electro-optic receiver; the fuse system further comprising a second electro-optic transmitter ; the second electro-optic transmitter being arranged to receive second electrical power , and to use that received second electrical power to transmit a second optical signal to the first electro-optic receiver; the first electro-optic receiver being arranged to receive the second optical signal, and to use that received second optical signal to transmit electrical power to the element of the fuse system connected to the first electro-optic receiver; wherein the second electro-optic transmitter is arranged to receive first electrical power from a power source of the fuse system, wherein the first electro-optic transmitter is arranged to receive second electrical power from a power source external to the fuse system; wherein the element is only able to receive power derived from the power source external to the fuse system via the first optical signal sent via the first electro-optic transmitter and first electro-optic receiver; and wherein the element is only able to receive power derived from the power source of the fuse system via the second optical signal sent via the second electro-optic transmitter and first electro-optic receiver. <EOS>