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You cannot do it if you have a 4-wire system. You will need an emonTx with 3 CTs, and run the 3-phase sketch.

You will probably be better using a Raspberry Pi and RFM69Pi radio board with an emonTx (or maybe without the radio board if you can use a serial connection), and load the emonCMS SD image onto your Pi.

(You could have done it with a 3-wire system, because then you need only 2 CTs.)

Thanks for the quick answer. My kit [ordered] has the following components:

3 x 100A max clip-on current sensor CT
1 x emonGLCD - LCD Display Unit - Kit
1 x emonTx V3 - Electricity Monitoring Transmitter Unit - 433MHz
1 x emonPi

So I assume, I can connect the emonTx to the emonPi and then use CT clips?

Where would I need to connect the clips to measure the total load for the building?

Take a look at the Resources > Building Blocks pages to see how to measure 3 phases - basically one on each phase. They need to go on the incomer before any distribution board, but they can be either side of your meter. The "connection" between your emonTx and emonPi is by radio. If you want to measure real power, you must have an ac adapter and load the 3-phase sketch into your emonTx. If you only want apparent power (VA), then the standard sketch is adequate. If you do not have the ac adapter, you cannot measure real power (because there is no voltage reference to determine relative phase) and the VA readings will be an approximation because you will be using the nominal system voltage rather than the actual.