A power system configured to generate and distribute DC electrical power, the power system comprising: a photovoltaic, "PV", system comprising: an array of PV modules (102; 406) electrically coupled to a combiner box; and an inverter (116; 316; 402) positioned to receive DC electrical power from the array of PV modules and output AC electrical power; a signal generator (220; 320; 414) coupled to a first portion of the PV system, characterized in that the signal generator is an acoustic generator configured to generate a first signal as an acoustic signal; and in that the power system further comprises: a signal detector (222; 322; 416) coupled to a second portion of the PV system, the signal detector configured to detect second signals generated at a loose connection of an electrical joint in the PV system in response to the acoustic signal, wherein the second signals result from the acoustic signal generated by the signal generator (220; 320) wherein the signal generator (220; 320; 414) and the signal detector (222; 322; 416) are positioned such that the acoustic signal generated by the signal generator and detected by the acoustic signal detector does not pass through the loose connection but passes to one or more electrical components adjacent the loose connection at which the detected second signals are generated. a photovoltaic, "PV", system comprising: an array of PV modules (102; 406) electrically coupled to a combiner box; and an inverter (116; 316; 402) positioned to receive DC electrical power from the array of PV modules and output AC electrical power; an array of PV modules (102; 406) electrically coupled to a combiner box; and an inverter (116; 316; 402) positioned to receive DC electrical power from the array of PV modules and output AC electrical power; a signal generator (220; 320; 414) coupled to a first portion of the PV system, characterized in that the signal generator is an acoustic generator configured to generate a first signal as an acoustic signal; and in that the power system further comprises: a signal detector (222; 322; 416) coupled to a second portion of the PV system, the signal detector configured to detect second signals generated at a loose connection of an electrical joint in the PV system in response to the acoustic signal, wherein the second signals result from the acoustic signal generated by the signal generator (220; 320) wherein the signal generator (220; 320; 414) and the signal detector (222; 322; 416) are positioned such that the acoustic signal generated by the signal generator and detected by the acoustic signal detector does not pass through the loose connection but passes to one or more electrical components adjacent the loose connection at which the detected second signals are generated. a signal detector (222; 322; 416) coupled to a second portion of the PV system, the signal detector configured to detect second signals generated at a loose connection of an electrical joint in the PV system in response to the acoustic signal, wherein the second signals result from the acoustic signal generated by the signal generator (220; 320) wherein the signal generator (220; 320; 414) and the signal detector (222; 322; 416) are positioned such that the acoustic signal generated by the signal generator and detected by the acoustic signal detector does not pass through the loose connection but passes to one or more electrical components adjacent the loose connection at which the detected second signals are generated.