Electronic Energy Meter role of two current signals

Not to prevent reverse stealing the zero line of fire is to prevent a fire in one place stealing, simple point that ordinary energy meter is only collected
FireWire current, can be  electric transformer  wiring or changing the current passing through the meter FireWire smaller or zero, in order to  Circuit breaker stealing. In this case the zero line of fire  circuit breakers  the meter currents are the same size, while the fire detecting the zero line current, the current by comparing the two signals, using the value of the current signal measured that way, to achieve anti-tamper results.