An electrical protection device including: at least two input terminals (2, 3) for electrically connecting respectively to an active conductor and a neutral conductor of an electrical power source that is upstream of the protection device; at least two output terminals (12, 13) for electrically connecting to a load having a conductive chassis that is downstream of the protection device, the load drawing a load current; a first sensor for providing a first signal derived from the load current, characterised in that the electrical protection device further includes: a second sensor for providing a second signal derived from a voltage differential between the chassis and a voltage reference; a processing unit that is responsive to a combination of both the first and second signals for selectively generating a fault signal, wherein the processing unit includes a processor that executes a predetermined algorithm which is responsive to the first and second signals for selectively generating the fault signal; and a switching unit that is responsive to the fault signal for progressing from a first state to a second state, wherein: in the first state the input terminals (2, 3) are electrically connected to the output terminals (12, 13) to allow the load current to be drawn from the source to the load; and in the second state the input terminals (2, 3) are electrically isolated from the output terminals (12, 13) and prevent the load current being drawn from the source to the load. at least two input terminals (2, 3) for electrically connecting respectively to an active conductor and a neutral conductor of an electrical power source that is upstream of the protection device; at least two output terminals (12, 13) for electrically connecting to a load having a conductive chassis that is downstream of the protection device, the load drawing a load current; a first sensor for providing a first signal derived from the load current, characterised in that the electrical protection device further includes: a second sensor for providing a second signal derived from a voltage differential between the chassis and a voltage reference; a processing unit that is responsive to a combination of both the first and second signals for selectively generating a fault signal, wherein the processing unit includes a processor that executes a predetermined algorithm which is responsive to the first and second signals for selectively generating the fault signal; and a switching unit that is responsive to the fault signal for progressing from a first state to a second state, wherein: in the first state the input terminals (2, 3) are electrically connected to the output terminals (12, 13) to allow the load current to be drawn from the source to the load; and in the second state the input terminals (2, 3) are electrically isolated from the output terminals (12, 13) and prevent the load current being drawn from the source to the load. a second sensor for providing a second signal derived from a voltage differential between the chassis and a voltage reference; a processing unit that is responsive to a combination of both the first and second signals for selectively generating a fault signal, wherein the processing unit includes a processor that executes a predetermined algorithm which is responsive to the first and second signals for selectively generating the fault signal; and a switching unit that is responsive to the fault signal for progressing from a first state to a second state, wherein: in the first state the input terminals (2, 3) are electrically connected to the output terminals (12, 13) to allow the load current to be drawn from the source to the load; and in the second state the input terminals (2, 3) are electrically isolated from the output terminals (12, 13) and prevent the load current being drawn from the source to the load.