Model 4630 performs both ground resistance and soil resistivity tests. This tester measures from 0 to 2000 Ohm, and is auto-ranging, so it automatically seek out the optimum measurement range. Easy-to-use: simply connect the leads, press-to-measure and read the results. The large LCDs (nearly 3/4 inches high characters) are easy-to-read, and also indicate low battery status, overrange, test lead shorts and lead reversals. 3 LED indicators on the front panel continuously warn the user of measurement problems to ensure accurate and reliable tests. Model 4630 is fuse protected up to grater than 250VAC against accidental connection to live circuits. In the event of a system fault, it can withstand 250VAC with spikes of up to 3000VAC or 1000VDC. The heavy-duty field case is sealed against dust and water when closed. The meter itself is self-contained within an inner case providing additional environmental and insulation protection. The test button is also sealed against the elements. Model 4630 is powered by a 9.6V, 3.5 Ah NiMH rechargeable battery pack. A built-in recharge circuit, powered from 120/230V 50/60Hz line, also provides for testing while recharging. Model 4630 is rugged, easy-to-use instruments ideal for maintenance crews performing numerous tests. This model exceed mechanical and safety specifications for shock, vibration and drop tests called out in IEC standards. They are designed to reject high levels of interference, so they can be used under difficult conditions such as high stray currents that normally affect accuracy. Measures soil resistivity (4-point) method; measures ground resistance (2- and 3-point) fall-of-potential method; step voltage tests and touch potential measurements. Auto-ranging: automatically selects the optimum range; designed to reject high levels of noise interference; extremely simple to operate: connect-press-read.