The 330B allows for non invasive current measurements. It measures AC current up to 1000A, AC voltage to 750V, DC voltage to 1000V and resistance to 2000M ohms.
The B&K Precision Model 325 AC/DC True RMS Power Clamp Meter provides safe, non-invasive measurements of up to 400KW, 400 Amps AC, and measures up to 600 Volts AC/DC.