SEW 1120ER 3 Wire Digital Earth Resistance Tester
Earth resistance can be measured directly from 0.01 ohms up to 1999 ohms. The reading is displayed on a large, easy-to-read digital display. The reading can be adjusted to 0Ω as a baseline control reading when shortcircuiting all of the test leads.
The SEW 1120 ER makes measurements by passing a constant current through the device being tested and measuring the voltage across it. The earth resistance is then calculated by Ohm’s Law.
The advanced circuitry of SEW 1120 ER permits the instrument to operate with minimal influence from earth voltage and earth resistance of the auxiliary spikes.
. The calibration of the instrument is performed with the included test leads. When using all three test leads in the three-terminal method, accuracy is assured for most common applications. Alternatively, two-terminal measurements, though generally less accurate than three-terminal measurements, are also possible by shorting the P and C terminals or by using the simplified measurement probe.
The test frequency of 820Hz avoids stray currents at power frequencies and their harmonics. Additionally, the 1120 ER utilizes a built-in filter to reject unwanted signals. The batteries are constantly being checked while in use. The rugged case is ideal for outdoor work. Earth electrode testing, which is an important part of electrical installation and maintenance procedures, is made easy with the 1120 ER. It can be used by electrical contractors or maintenance engineers to check the effectiveness of their earth electrode systems.
SEW 1120ER Specifications:
|Measuring ranges|| Earth resistance
0-20Ω / 0-200Ω / 0-2000Ω
|Accuracy|| Earth resistance
±(2%rdg+2dgt) at 200/2000Ω
±(2%rdg+0.1Ω) at 20Ω
Earth voltage ±(1%rdg+2dgt)
| Earth resistance
| 0-20Ω : 0.01Ω
0-200Ω : 0.1Ω
0-2000Ω : 1Ω
|Measuring system|| Earth Resistance by constant
current inverter 820Hz approx. 2mA
|Display||3½ digit (2000 counts)|
| Open circuit
|LED will be unlit|
| Low battery
|“Battery” symbol appears on the display|
| Data hold
|“Hold” symbol appears on the display|
| Over range
|Dimensions||250(L) × 190(W) × 110(D)mm|
|Power source||1.5V (AA) × 8|
|Safety standards|| EN 61010-1 CAT III 300V
IEC 61557-1 IEC 61557-5