Split core CTs can be extended with 600V rated twisted pair wire to cover much longer distances. STP (shielded twisted pair) is recommended, as it will reduce noise and interference. If you need to extend a CT wire farther than approximately 100 ft (30m), contact eGauge support to see if a custom factor will be necessary in your software settings.
Note that CT leads longer than approximately 100ft (30m) can cause a decrease in accuracy. This is especially true of CTs with high maximum amperage ratings which are reading extremely low amperages.
eGauge typically recommends 600V rated CAT 5 Ethernet cable, as it is generally easy to obtain and can be used to extend up to 4 CTs. However, any shielded twisted pair wire with appropriate insulation and wire gauge can be used.
Please see the CT selection guide for full details regarding CTs.