An electrical installation comprising control and/or monitoring means connected to a field device by means of an electrical communications circuit, in which the communications circuit comprises a power supply, a communications device, the field device as a load thereof, and Intrinsic Safety means, in which the communications device is adapted to send and receive signals over the communications circuit to and from the field device, in which the field device is adapted to send and receive signals over the communications circuit to and from the communications device, in which the Intrinsic Safety means renders all or part of the communications circuit Intrinsically Safe, in which the field device is located in an Intrinsically Safe part of the communications circuit, characterised in which the communications circuit is adapted to carry DSL signals, and in which the communications device and the field device communicate with one another according to the DSL protocol.