earth ground tester 3 pole fall of potential

{"cid":"91202321","title":"Fluke 1623-2 GEO Earth Ground Tester Kit 1623-2 GEO Earth Ground Resistance Meter","imgUrl":"https:\/\/img.chinax.com\/nimg\/30\/21\/676d698b271ee3f5c7a270272188-200x200-1.jpg","attrs":{"Price":"USD$1450\/PC","Brand Name":"Fluke","Model Number":"1623-2","Minimum Order Quantity":"1","Delivery Time":"1 Weeks","Certification":"CCC,CE","Place of Origin":"USA","Payment Terms":"L\/C, D\/A, D\/P, T\/T, Western Union, MoneyGram","Supply Ability":"100","Packaging Details":"Original","Product Type":"Earth Ground Resistance Meter","Display":"Display with special symbols, digit height 25 mm, fluorescent backlight","Operating temperature":"-10\u00b0C to 50\u00b0C","Storage temperature":"-30\u00b0C to 60\u00b0C","Temperature coefficient":"\u00b10.1% of reading\/\u00b0C","Measure frequency":"128 Hz","Short-circuit current":"> 50 mA","Measuring voltage":"Vm = 48 V AC"}}