CM E1 - Multimeter BENNING - Free user manual and instructions

USER MANUAL CM E1 BENNING

FUNC REC REC NO. NOISE m VA

FUNC REC REC NO. NOISE m VA

Earth measuring clamp for - earth loop resistance measurement - AC current/ leakage current measurementTable of contents1. User instructions2. Safety instructions3. Scope of delivery4. Device description5. General information6. Ambient conditions7. Electrical specifications8. Measuring with the BENNING CM E19. Maintenance10. Environmental note1. User instructionsThis operating manual is intended for - skilled electricians and - electrotechnically trained personnel.The BENNING CM E1 is intended for measurements under dry ambient conditions. It must not be used in electrical circuits with a nominal voltage higher then CAT III 300 V (see section 6 „Ambient conditions“ for details).The following symbols are used in this operating manual and on the BENNING CM E1: Application around and removal from HAZARDOUS LIVE conductors is permitted.Warning of electrical danger! Indicates instructions which must be followed to avoid danger to persons.Attention! Must comply with documentation! This symbol indicates that the information provided in the operating manual must be complied with in order to avoid risks.CAT IIICAT III Measuring category III is applicable to testing and measuring circuits connected to the distribution circuit of the low-voltage mains installation of a building. This symbol on the BENNING CM E1 indicates that the BENNING CM E1 is equipped with pro-tective insulation (protection class II).Please observe the operating manual!This symbol appears on the display to indicate a discharged battery. (AC) Alternating voltage or current Ground (voltage against ground)09/ 2019

The instrument is built and tested in accordance with DIN VDE 0411 Part 1/ EN 61010-1 DIN VDE 0411 Part 2-032/EN 61010-2-032 DIN VDE 0413 Part 5/EN 61557-5 DIN VDE 0843-20 Part 1/EN 61326-1 and has left the factory in perfectly safe technical condition. To preserve this condition and to ensure safe operation of the device, the user must observe the notes and warnings given in these instructions at all times. Improper handling and non-observance of the warnings might involve severe injuries or danger to life.

WARNING! Be extremely careful when working with bare conductors or main line carrier! Contact with live conductors will cause an electric shock!

Before starting the current clamp multimeter, always check the device as well as all mea- suring leads for damages. If it can be assumed that safe operation is no longer possible, switch the device off immediately and secure it against unintended operation. Safe operation can be assumed to be no longer possible, if - the device exhibit visible damages, - the device no longer works, - the device has been stored under unfavourable conditions for a longer period of time, - the device was exposed to extraordinary stress during transport, or - if the device is are exposed to moisture.

Maintenance: Do not open the multimeter, because it contains no components which can be repaired by the user. Repair and service must be carried out by qualified personnel only!

Cleaning: Regularly wipe the housing by means of a dry cloth and cleaning agent. Do not use any polishing agents or solvents!

3. Scope of delivery

The scope of delivery of the BENNING CM E1 comprises:

3.1 One BENNING CM E1

3.2 One transport case with shoulder strap (10217859)

3.3 One reference earth resistance loop (10217860)

3.4 One 9 V block battery (IEC 6 LR 61)

3.5 One operating manual

Parts subject to wear: - The BENNING CM E1 is supplied by means of one 9 V block battery (IEC 6 LR61).

4. Device description

see figure 1: Appliance front face The display and operating elements shown in figure 1 are designated as follows:

Measuring clamp, for clamping the earthing conductor/earth connection

HOLD key, storage of the indicated measured value

Rotary switch, for selecting the measurement function

REC key, for starting the data logger/storage

▼ key, decreases the setting value

Opening lever, for opening and closing the current prongs

▲ key, increases the setting value

FUNC key, function key for selecting alarm thresholds, sampling rate and storage location number09/ 2019

see figure 2: Digital display The symbols shown in fig. 2 are designated as follows: A Secondary display, for function selection and storage location number B Digital display, for measured value, alarm threshold, sampling rate C Ω Ohm, unit of loop resistance measurement D mA, unit of current/ leakage current measurement E , loop resistance measurement with acoustic alarm function F NOISE, detection of interfering signals, measurement might be affected G , measuring clamp is not closed correctly H , battery status indication I NO., storage location number J REC, data logger is enabled K AP, automatic switch-off is enabled (APO active)

5. Functions of the earth measuring clamp

highest numerical value to be displayed is 9999.

5.1.2 The range exceedance is indicated by „OL“.

Attention, no other indication and warning in case of overload!

is intended for selecting the measuring function. The selection of the measur- ing range is automatic.

5.1.4 HOLD key function: The measuring result can be stored by pressing the HOLD key

. The “H” symbol simultaneously appears on the display

5.1.5 REC key function: for starting the data logger or storing a measured value in the internal memory

5.1.6 FUNC function key: function key for selecting the alarm thresholds “HI” (high), “LO” (low), the

sampling rate “SEC” (seconds) and storage location number “NO.” (1-116)

5.1.7 The nominal measuring rate of the BENNING CM E1 is 2 measurements per second.

5.1.8 The BENNING CM E1 is switched on and off with the rotary switch

. Shutdown position “OFF”.

5.1.9 The BENNING CM E1 switches off automatically after approx. 4 min. to 6 min. (APO, Auto-Power-

Off is enabled if the “AP” symbol K is shown on the display

It switches on again as soon as the rotary switch

is switched on again from switch position “OFF”. Automatic switch-off can be deactivated by pressing the FUNC key and by simultaneously switching on the BENNING CM E1 from the switching position “OFF”. The symbol AP K disap- pears from the display

5.1.10 The BENNING CM E1 is supplied by a fitted 9 V block battery (IEC 6 LR 61).

5.1.11 If the battery voltage drops below the specified operating voltage of the BENNING CM E1, then a

battery symbol H appears in the display

5.1.12 The battery life depends on the measuring function used and is intended for approx. 3000 mea-

5.1.13 Temperature coefficient of the measured value: 0.1 x (stated measuring accuracy)/ °C < 18 °C or

> 28 °C, related to the value for the reference temperature of 23 °C.

5.1.14 Dimensions of unit (length x width x height) = 276 x 100 x 47 mm

Weight of unit: approx. 750 g (incl. battery)

5.1.15 Widest prong opening: 38 mm

5.2 Setting the alarm thresholds of the earth loop resistance

To measure the earth loop resistance, an upper (HI) and lower (LO) alarm threshold can be set. Use the rotary switch

until the “HI” symbol or “LO” symbol appears on the secondary display A. By pressing the ▼ key

, the alarm threshold can be set from 0 ohms to 1510 ohms or “OL” respectively. After having set one alarm threshold or both, press the FUNC key

until the symbols on the secondary display A disappear. As soon as the rotary switch position Ω+ is selected, the earth measuring clamp compares the displayed value with the upper and lower alarm thresholds. If the displayed value is higher than the upper alarm threshold, a pulsating acoustic signal is emitted and the “HI--” symbol is displayed. If the displayed value is lower than the lower alarm threshold, a pulsating acoustic signal is emitted and09/ 2019

the “LO--” symbol is displayed. Note: - To disable the alarm thresholds, set the upper alarm (HI) to “OL” and the lower alarm (LO) to “0”. - The upper alarm (HI) cannot be lower than the lower alarm (LO), and the lower alarm (LO) cannot be higher than the upper alarm (HI). - When the data logger is enabled, the acoustic alarm function is disabled. - The alarm thresholds set remain stored until they are changed the next time.

5.3 Data logger function

The data logger function allows the automatic and manual storage of series of measurements (Funktion Ω/ Ω , mA/ A) with a predefined measuring interval (sampling rate) and up to 116 measured values. The measuring interval can be set from 1 s to 255 s. The measured values can be read out later by means of the display

several times until the “SEC” symbol appears on the secondary display A. The digital display B shows the sampling rate in seconds. Use the ▼ key

to set the sam- pling rate from 1 s to 255 s. Press and hold the keys to accelerate the setting process. Then, press the FUNC key

several times until the symbols on the secondary display A disappear. Note: To store only a single measured value, select a sampling rate of 0 s. Each time the REC key

is pressed, another measured value is stored in the internal memory and the storage location number is briefly shown on the secondary display A.

5.3.2 Starting and stopping the data logger

to start the data logger. At the same time, the REC symbol J appears on the digital display

. The measured values are stored in the internal memory taking into account the sampling rate set. The data logger can be stopped by pressing the REC key

and stops automatically as soon as the meas- ured value memory is full. The REC icon J on the digital display

several times until the “NO.” symbol I appears on the digital display

, the storage location number is selected via the secondary display A and the corresponding measured value is shown on the digital display B.09/ 2019

5.3.4 Deleting the measured value memory

Delete the complete measured value memory by pressing the REC key

and by simultaneously switching on the BENNING CM E1 from the switching position “OFF”. The “CL” symbol being shown on the display

means that the measured value memory has been deleted.

5.4 Functional principle of earth loop resistance measurement

Earth loop resistance measurement is one of the methods of measuring the earth resistance without using rods. It offers the advantage that no additional probes/auxiliary earth electrodes have to be installed and the earth connection itself does not have to be disconnected. The method is used, among other things, in electrical installations with several parallel earthing connections, such as overhead line networks with pole-type earth electrodes, lightning protection and street lighting systems. The BENNING CM E1 has a specially shielded measuring clamp

with integrated excitation winding and sensor winding. The excitation winding induces a current flow in the clamped earthing conductor/earth connection via a defined AC voltage E. The current flow I is measured via the sensor winding and the resistance of the entire earth loop Rs is calculated and displayed via the BENNING CM E1. Rs = E / I provided that: Rs = Rx + (R1 II R2 ... II RN) + Rb + Rl with (R1 II R2 …II Rn) << Rx and (Rb + Rl) < Rx results in Rs Rx This means that the earth loop resistance Rs measured by the BENNING CM E1 is always higher than the searched earth loop resistance Rx. The higher the number of parallel earth connections, the more accurate the displayed value Rs corresponds to the searched earth resistance Rx. If the displayed resistance value is too high, check the earth connection. Rs: Earth loop resistance (entire earth loop) Rx: Searched earth resistance R1 ... RN: Parallel earth connections, negligible the higher the number Rb: Resistance of the soil, usually <1 Ω Rl: Resistance of the earthing lines, usually <1 Ω see figure 3: Earth loop resistance measurement

6. Ambient conditions

- The BENNING CM E1 is intended for measurements under dry ambient conditions - Maximum barometric height for measurements: 2000 m - Overvoltage category / installation category: IEC 60664/ IEC 61010 → 300 V category III - Contamination class: 2 according to EN 61010-1 - Protection class: IP 30 (DIN VDE 0470-1, IEC/ EN 60529) IP 30 means: Protection against access to dangerous parts and protection against solid impurities of a diameter > 2.5 mm, (3 - first index). No protection against water, (0 - second index). - Operating temperature and relative humidity: For operating temperatures from 0 °C to 50 °C: relative air humidity lower than 85 %, noncondensing. - Storage temperature: The BENNING CM E1 can be stored at temperatures between - 20 °C and + 60 °C, at a relative air humidity lower than 75 % without batteries.

7. Electrical specifications

Note: The measuring accuracy is specified as the sum of: - a relative part of the measured value and - a number of digits (i.e. counting steps of the last digit). This measuring accuracy applies to temperatures from 23 °C ± 5 °C and a relative air humidity lower than 80 %.09/ 2019

7.1 Loop resistance ranges

Measuring range Resolution Measurement accuracy

valid for purely ohmic resistances, external magnetic field <30 A/m, external electric field <1 V/m Measuring frequency: 3.333 kHz Accuracy of the reference resistance loop: approx. ± 1 % Alarm threshold Range Resolution Upper alarm (HI) 0 - 1510 Ω 1 Ω Lower alarm (LO) 0 - 1510 Ω 1 Ω

7.2 AC current/ leakage current

The measured value is obtained and displayed as real r.m.s. value (True RMS, AC coupling). Its calibration is adapted to sinusoidal curves. In case of deviations from this curve shape, the accuracy of the displayed value decreases. Crest factor < 3.5 Measuring range Resolution Measurement accuracy in frequency range 50 Hz - 60 Hz

8. Measuring with the BENNING CM E1

8.1 Preparation for measuring

Operate and store the BENNING CM E1 at the specified storage and operating temperatures only! Do not permanently expose the device to sunlight. - Strong sources of interference in the vicinity of the BENNING CM E1 might involve unstable readings and measuring errors.

8.2 Loop resistance measurement

Do not exceed the maximum permitted voltage with respect to earth potential! Electrical danger! - Open the measuring clamp and check whether the metallic contact surfaces inside the clamp are free of dust and contamination. - Let the jaws of the measuring clamp snap together several times (open and close them) in order to establish a safe contact. - Use the rotary switch

to select the function Ω (loop resistance) or Ω+ (loop resistance with alarm). Wait until the end of the self-calibration (CAL 7, CAL 6, ..., CAL 2, CAL 1) is confirmed by an acoustic signal and the “.OL” symbol appears on the digital display B.09/ 2019

- Open the measuring clamp and clamp the earthing conductor/earth connection to be tested. Let the jaws of the measuring clamp snap together again several times. - The measured value of the earth loop resistance can be read on the digital display B. Note: - During self-calibration, do not place the measuring clamp

around a conductor or open the measuring clamp. - If self-calibration does not stop, check whether the metallic contact surfaces inside the clamp are free of dust and contamination. - If interfering signals (current >3 A, voltage >30 V) are detected during the measurement, the “NOISE” symbol F appears on the digital display

and the measurement might be affected. - If the clamp was not closed correctly during the measurement, the symbol G appears on the digital display

see fig. 3: Earth loop resistance measurement

8.3 AC current/ leakage current measurement

Do not exceed the maximum permitted voltage with respect to earth potential! Electrical danger! - Use the rotary switch

of the BENNING CM E1 to select the desired function mA or A. - Open the measuring clamp

and clamp the earthing conductor/earth connection to be tested. - The measured value of the leakage current can be read on the digital display B. see figure 4: AC current/ leakage current measurement

Before opening the BENNING CM E1, strictly observe that the device is free of voltage! Electrical danger!

9.1 Securing the device

Under certain circumstances, safe operation of the BENNING CM E1 might no longer be ensured, e.g. in case of: - visible damage of the casing. - incorrect measuring results, - recognizable consequences of prolonged storage under inadmissible conditions and - recognizable consequences of extraordinary stress due to transport. In such cases, immediately switch off the BENNING CM E1, disconnect it from the measuring points and secure it against further use.

Clean the exterior of the device with a clean dry cloth (exception: special cleaning wipers). Do not use any solvents and/or abrasives to clean the device. Make sure that the battery compartment and the battery contacts are not contaminated by leaking battery electrolyte. If there are electrolyte contamination or white deposits in the area of the battery or the battery compart- ment, clean these areas as well by means of a dry cloth.

9.3 Battery replacement

Before opening the BENNING CM E1, strictly observe that the device is free of voltage! Electrical danger! The BENNING CM E1 is fed by a 9 V block battery. The battery must be replaced (see fig. 5) when the battery symbol H appears in the display

. When the BENNING CM E1 is switched on, a battery test is carried out. Proceed as follows to replace the battery: - Switch off the BENNING CM E1. - Put the BENNING CM E1 face down and unscrew the screws of the bottom part of the housing. - Lift the bottom part of the housing off the front part. - Lift the discharged battery from the battery compartment and disconnect the battery supply lines from the battery.09/ 2019

- The new battery have to be connected to the battery supply lines, and arrange these such that they are not crushed between the housing parts. Then, insert the new battery into the front part at the provided place. - Lock the bottom part of the housing into place on the front part and tighten the screws. see figure 5: Battery replacement

Make your contribution for environmental protection! Do not dispose of discharged bat- teries via the household waste. Instead, return them to a collecting point for discharged batteries or spezial waste. Please look for information in your community‘s facilities.

Benning guarantees compliance with the technical and accuracy specifications stated in the operating manual for the first 12 months after the delivery date. To maintain accuracy of the measuring results, the device must be recalibrated in regular intervals by our factory service. We recommend recalibrating the device once a year. For this purpose, send the device to the following address: Benning Elektrotechnik & Elektronik GmbH & Co. KG Service Center Robert-Bosch-Str. 20 D - 46397 Bocholt

10. Environmental note

At the end of product life, dispose of the unserviceable device via appropriate collecting facilities provided in your community.09/ 2019 BENNING CM E1