DET14C.

DET14C and DET24C Digital Earth Clamps DET14C and DET24C Digital Earth Clamps ■■ Elliptical clamp shape improves access to earth cables and straps up to 50 mm ■■ Low maintenance flat jaw interface ■■ Measures ground resistance from 0.05 Ω to 1500 Ω ■■ Measures true RMS ground leakage current from 0.5 mA rms to 35 A rms ■■ CAT IV 600 V safety rating ■■ Backlit LCD Display DESCRIPTION The DET14C and DET24C represent a new generation of earth/ ground clamp-on resistance testers. These instruments induce a test current into earth systems and measure ground resistance in multi ground installations without needing to disconnect the ground. They offer market leading access, advanced features, simple operation and CAT IV 600 V safety protection. Designed with flat core ends they prevent dirt build up, ensuring measurement integrity and improved reliability over products with interlocking teeth. Other enhancements over current generation products include improved accuracy and up to 300% increase in battery life. In electrically noisy environments the built-in filter function offers increased noise immunity. DET14C and DET24C also offer a true RMS AC current measurement facility up to 35 Amps. The instrument’s ability to measure current flowing in an earth cable is a useful safety feature, especially if the earth cable has to be disconnected. A high current flow to earth could draw an arc on dis-connection with potentially severe consequences. The elliptical shaped head design offers improved access to cables and earth straps in space constrained locations. The clamp head accommodates up to 37 mm diameter cable and 50 mm earth tapes making them suitable for use in power stations, substations, towers and many more facilities. Operation in dark and restricted areas is facilitated by a display with backlight and an audible tone associated with the hold key. Optimised jaw opening mechanism ensures proper jaw closure without excessive use of force when opening the jaws. The DET14C offers storage of results for later on-screen recall and the DET24C supports a download of results via Bluetooth® into PowerDB and PowerDB Lite, Megger’s acceptance and maintenance test data management software. Stored data is indexed using a sequential serial number together with a time and date stamp for each record. APPLICATION The earth resistance clamp meters are particularly suitable for measuring earth resistance in various installations such as buildings, pylons and RF transmitter sites without system disconnection. In addition, they can be used for the inspection and verification of lightning protection systems and virtually any installation where a current loop can be generated. FEATURES AND BENEFITS nn Auto-current measurement safety feature nn Memory to record and view results nn Automatic self calibration nn Auto ranging nn High and low alarms nn Real time clock for date and time stamping of results DET24C ADDITIONAL FEATURES nn Bluetooth® stored test results transfer to PC nn Advanced memory functionality with download nn Megger PowerDB/PowerDB Lite™ compatible DET14C and DET24C Digital Earth Clamps SPECIFICATIONS Resistance measurements Maximum jaw opening 39 mm Ground resistance certainty Resolution Intrinsic range Maximum jaw inner dimensions 39 mm x 55 mm 0.05 Ω to 0.99 Ω 0.01 Ω ±1.5% ±0.05 Ω Display 4 + 6 digit with backlight 1.00 Ω to 9.99 Ω 0.01 Ω ±1.5% ± 0.1Ω Battery type 4 x 1.5 V IEC LR6/AA alkaline 10.0 Ω to 99.9 Ω 0.1 Ω ±2% ±0.5 Ω 100.0 Ω to 199.9 Ω 0.1 Ω ±5% ±1 Ω 200 Ω to 400 Ω 1 Ω ±10% ±10 Ω 400 Ω to 600 Ω 1 Ω ±10% ±10 Ω Battery life 24 hours continuous testing - see Note 1 Note 1: Whilst measuring a 25 Ω resistance without backlight 600 Ω to 1200 Ω 10 Ω ±20% 1200 Ω to 1500 Ω 10 Ω ±35% Auto power down 300 s (reset by jaw action or button press) Data logging DET14C 256 records DET24C 2 k records Frequency of measurement 1390 Hz. The specification stated above is only maintained if the Jaws of the DET14C and DET24C are kept clean at all times. Alarm settings Alarm type Range Resolution Threshold 1 1 Ω to 1500 Ω 1Ω Threshold 2 1 Ω to 1500 Ω 1Ω Current range (RMS) Current range Resolution Intrinsic Certainty 0.5 mA to 0.99 mA 0.01 mA ±2% ±0.05 mA 1.00 mA to 9.99 mA 0.01 mA ±2% ±0.05 mA 10.0 mA to 99.9 mA 0.1 mA ±2% ±0.1 mA 100 mA to 999 mA 1 mA ±2% ±1 mA 1.00 A to 9.99 A 0.01 A ±2% ±0.01 A 10.0 A to 35.0 A 0.1 A ±2% ±0.1 A True RMS readings up to a crest factor of 5.0 (peak current 40 A). Accuracy guaranteed for 50 Hz and 60 Hz. Data download Bluetooth® interface (DET24C only) Range Selection: Automatic within each mode Sampling time