Fluke i40s el 3pk current clamp transformer set for mains analyser 1730 fluke 4357438 the fluke i40s el is a clamp on current transformer that is used in conjunction with the fluke 1730 three phase electrical energy logger for low current measurement it is suitable for making measurements up to 40a and also measures accurately on 1a and 5a secondary current transformers the i40s el jaw is capable of being clamped on current conductors up to 15mm in diameter fluke i40s el 3pk current clam