Abstract: An alarm system for warning of unbalance or failure of one or more phases of a multi-phase load circuit which is convenient and practical to use even where the load circuit is drawing a large current and where the flow of power to the load may be controlled by various devices, said alarm system including a three-phase resistance bridge circuit with a phantom neutral point at the common juncture of three similar resistances connected in a Y-pattern and each shunted across a secondary winding of transformers having magnetic cores encircling the power leads to the load circuit and with the outer terminals of these resistors connected through resistance elements to the adjustable taps of three potentiometers included in the respective legs of a second Y pattern having the outer ends of these legs connected to the respective load phases for defining a second neutral point at their common junction.