Split core current transformers from the QI-SC range are available with secondary at 5 A in the following sizes:

QI-SC-24: Internal diameter 24 mm for 100, 200 and 300 A currents, including 1 metre integrated cable
 QI-SC-36: Internal diameter 36 mm for 300, 400 and 600 A currents, including 1 metre integrated cable
 QI-SC-DBP23: Internal diameter 20 x 30 mm for 100, 200, 300 and 400 A currents
QI-SC-DBP58: internal diameter 50 x 80 mm for 400, 600, 800 and 1000 A currents