The Siemens 7KT1670 is the direct-connected 80 A variant of the PAC1600 series with S0 pulse output. It wires directly into the three-phase supply without external current transformers, making it the simplest PAC1600 to install for loads up to 80 A. The S0 pulse interface feeds energy data to pulse counters, data loggers, and BMS digital inputs.

Direct 80 A connection — when does this work and when do I need CTs?

With 80 A direct connection, the meter's internal current path carries the full load current through screw terminals sized for conductors up to 25 mm². This works for most branch circuits, small distribution panels, and individual machine supplies. However, the 80 A rating is the maximum continuous current — if your load exceeds 80 A, you must use a CT-connected model (7KT1672 or 7KT1673) with appropriately sized external current transformers. There is no way to extend the 7KT1670's range with external CTs.

What does the S0 pulse interface give me — and what does it not?

The S0 output provides accumulated energy pulses (active and reactive on two separate channels) to external counters. Each pulse equals a fixed energy quantum. This is ideal for: remote totalization via pulse counter, input to a BMS or energy data logger with digital inputs, and simple kWh monitoring without a communication network. What S0 cannot do: transmit instantaneous values (voltage, current, power factor), support remote configuration, or provide alarm/warning flags. For those capabilities, consider the Modbus RTU or M-Bus variants.

Frequently Asked Questions

What cable size fits the 80 A direct terminals?

The screw terminals accept conductors up to 25 mm², which is adequate for 80 A continuous current with standard PVC-insulated copper cable. Always follow local wiring regulations for conductor sizing and overcurrent protection upstream of the meter.

Does the 7KT1670 need an auxiliary power supply?

No. Like all PAC1600 three-phase meters, the 7KT1670 is self-powered from the measured voltage — no separate auxiliary supply wiring is needed. The meter powers up as soon as voltage is present on the L-N terminals.