This work proposed a new real time monitoring system in distribution transformer with communication through a ZigBee network. It obtains the voltage, current, power, energy and frequency of all loads connected at the distribution transformer. The information collected in the measurements are send to a server through a ZigBee network for safe the information. The new real time system build a wireless network with low energy consumption and a large transmission distance with enough conditions to work in an urban distribution electric network. This system make possible a low cost infrastructure to do a task of save electric magnitude as well as possible diagnostic of the electrical network.