A method and an arrangement are disclosed for monitoring connections of a switch intended for activating a safety function, the switch having at least two poles. The arrangement can supply voltages to first sides of two poles of the switch through first connections, and monitor the voltages supplied through the switch and further from second sides of the two poles of the switch to a device through second connections. The arrangement can form a voltage difference between the voltages to be supplied to the first sides of the two poles of the switch, and detect a connection failure when the difference between the voltages supplied to the device does not correspond with the formed voltage difference or when the difference between the voltages supplied to the device is substantially zero.