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Hi Jon,

Its fantastic that you want to build such as system. My advice woudld be to start small and build up.

The emonTx and AC mains non-invasive V3 energy monitors which are documented on the site work by cliping at CT sensor round either the positive or negative supply cable. This works well for monioring total household consumption since the CT can easily be clipped round one of the positive or negative 'tails' where they are seperate as they feed into utility meter.

To you a CT to monitor individual applications you will need to bae able to clip a CT sensor round the individual (positive or negtive) cable going to the individual applience. Access to where the positive and negative wires are seperate can be difficult. 

In therory multiple emonTx's communicating wirelessly to an emonBase web connected base station could perform this task. 

Like I said my advice would be to start small and build up, maybe get a total house consumption monitor up and running first. Setting up an emonTx and emonBase requires some solidering skills and familiarity with the Arduino enviroment and C++ is usefull.

Good luck, 

Glyn,

have you experimented with the max possible length for the CT sensors? Given a EmonTx has three inputs, it may be helpful for it to collect data for all appliances say in 2m range if the cable permits that length.
Maybe some adjustments to the calibration need to take place if the cable length is too great?

I'm not sure what the maximum length for a CT sensor cable is. A long length would effect the signal more when measuring light loads since the current will be small. 2m should be fine