An electrical device, the device comprising: a device startup or activation circuit; a power line sensor coupled to the device startup or activation circuit; and wherein the power line sensor is configured to dynamically sense electrical properties of power supplied by a power supply line for the device, and wherein the device startup or activation circuit is configured to slow or delay device startup or activation upon a sensed voltage drop on the power supply line at or about device startup or activation and/or about a peak power draw by the device from the power supply line, characterised in that the device further comprises: a signal-generating circuit configured to generate a signal indicative of power demand or use by the device, and in that the signal indicative of power demand or use by the device is at least one of: transmitted by the device according to a collision avoidance protocol, wherein the collision avoidance protocol includes transmission of the signal a random time interval after a determination that no other signal indicative of power demand or use by another electrical devices is present or detected propagating on the power supply line; and transmitted by the device according to a collision avoidance protocol, wherein the collision avoidance protocol includes transmission of the signal a device-specific time interval after a determination that no other signal indicative of power demand or use by another electrical devices is present or detected propagating on the power supply line. a device startup or activation circuit; a power line sensor coupled to the device startup or activation circuit; and wherein the power line sensor is configured to dynamically sense electrical properties of power supplied by a power supply line for the device, and wherein the device startup or activation circuit is configured to slow or delay device startup or activation upon a sensed voltage drop on the power supply line at or about device startup or activation and/or about a peak power draw by the device from the power supply line, characterised in that the device further comprises: a signal-generating circuit configured to generate a signal indicative of power demand or use by the device, and in that the signal indicative of power demand or use by the device is at least one of: transmitted by the device according to a collision avoidance protocol, wherein the collision avoidance protocol includes transmission of the signal a random time interval after a determination that no other signal indicative of power demand or use by another electrical devices is present or detected propagating on the power supply line; and transmitted by the device according to a collision avoidance protocol, wherein the collision avoidance protocol includes transmission of the signal a device-specific time interval after a determination that no other signal indicative of power demand or use by another electrical devices is present or detected propagating on the power supply line. transmitted by the device according to a collision avoidance protocol, wherein the collision avoidance protocol includes transmission of the signal a random time interval after a determination that no other signal indicative of power demand or use by another electrical devices is present or detected propagating on the power supply line; and transmitted by the device according to a collision avoidance protocol, wherein the collision avoidance protocol includes transmission of the signal a device-specific time interval after a determination that no other signal indicative of power demand or use by another electrical devices is present or detected propagating on the power supply line.