Benning CFlex 2 User manual

TRUE RMS
3000 A Ø 16 cm/L 46 cm
FLEXIBLE CURRENT METER
CFlex 2
BENNING CFlex 2
Operating manual

07/ 2014 BENNING CFlex 2
D  F E   I    
TRUE RMS
3000 A Ø 16 cm/L 46 cm
FLEXIBLE CURRENT METER
CFlex 2
Bild 1: Gerätefrontseite
Fig. 1: Appliance front face
Fig. 1: Partie avant de l‘appareil
Fig. 1: Parte frontal del equipo
Obr. 1: Přední strana přístroje
Σικόνα 1: Μπροστινή όψη
Ill. 1: Lato anteriore apparecchio
Fig. 1: Voorzijde van het apparaat
Rys. 1: Panel przedni przyrządu
Рис. 1: Вид спереди
Resim 1: Cihaz önyüzü
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07/ 2014 BENNING CFlex 2
D  F E   I    
TRUE RMS
3000 A Ø 16 cm/L 46 cm
FLEXIBLE CURRENT METER
CFlex 2
Bild 2 b: Wechselstrommessung
Fig. 2 b: Alternating current measurement
Fig. 2 b: Mesure de courant alternatif
Fig. 2 b: Medición de corriente alterna
obr. 2 b: Měření střídavého proudu
Σικόνα 2 b: Μέτρηση εναλλασσόμενης έντασης ρεύματος
ill. 2 b: Misura corrente alternata
Fig. 2 b: Meten van wisselstroom
Rys.2 b: Pomiar prądu przemiennego
Рис. 2 b: Измерение величины переменного тока
Resim 2 b: Alternatif akım ölçümü
Bild 2 a: Wechselstrommessung
Fig. 2 a: Alternating current measurement
Fig. 2 a: Mesure de courant alternative
Fig. 2 a: Medición de corriente alterna
obr. 2 a: Měření střídavého proudu
Σικόνα 2 a: Μέτρηση εναλλασσόμενης έντασης ρεύματος
ill. 2 a: Misura corrente alternata
Fig. 2 a: Meten van wisselstroom
Rys.2 a: Pomiar prądu przemiennego
Рис. 2 a: Измерение величины переменного тока
Resim 2 a: Alternatif akım ölçümü

07/ 2014 BENNING CFlex 2
D  F E   I    
25 mm 50 mm 75 mm
Bild 4: Batteriewechsel
Fig. 4: Battery replacement
Fig. 4: Remplacement de la pile
Fig. 4: Cambio de pila
Obr. 4: Výměna baterie
Σικόνα 4: Αντικατάσταση μπαταριών
Ill. 4: Sostituzione batterie
Fig. 4: Vervanging van de batterij
Rys. 4: Wymiana baterii
Рис. 4: Замена батареи
Resim 4: Batarya değişimi
Bild 3: Positionierungsfehler
Fig. 3: Positioning error
Fig. 3: Erreur de positionnement
Fig. 3: Error de posición
Obr. 3: Poziční chyba
Σικόνα 3: Σφάλμα θέσης
Ill. 3: Errore di posizione
Fig. 3: Positionering foutmarge
Rys. 3: Błąd położenia
Рис. 3: Погрешность позиционирования
Resim 3: Pozisyon hatası

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Operating Instructions
BENNING CFlex 2
Flexible digital TRUE-RMS AC current transformer for AC current measurement
Table of contents
1. User notes
2. Safety note
3. Scope of delivery
4. Unit description
5. General information
6. Ambient conditions
7. Electrical specifications
8. Measuring with the BENNING CFlex 2
9. Maintenance
10. Environmental note
1. User notes
These operating instructions are intended for
- qualified electricians and
- electrotechnically trained persons.
The BENNING CFlex 2 is intended for making measurements in dry environment. It must not be
used in power circuits with a nominal voltage higher than 600 V AC CAT IV/ 1000 V AC CAT III
(More details in Section 6. “Ambient conditions”).
The following symbols are used in these operating instructions and on the BENNING CFlex 2:
Application around and removal from NON-INSULATED HAZARDOUS LIVE
conductors is NOT permitted.
Warning of electrical danger!
Indicates instructions which must be followed to avoid danger to persons.
Important, comply with the documentation!
The symbol indicates that the information provided in the operating instructions must
be followed with in order to avoid risks.
This symbol on the BENNING CFlex 2 means that the BENNING CFlex 2 is totally
insulated (protection class II).
This symbol on the BENNING CFlex 2 means that the BENNING CFlex 2 complies
with the EU directives.
(AC) Alternating voltage or current.
Ground (Voltage against ground).

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2. Safety note
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 0411 part 031/ EN 61010-031
and has left the factory in perfectly safe technical condition.
To maintain this condition and to ensure safe operation of the unit, the user must observe the
notes and warnings given in these instructions at all times. Improper handling and non-obser-
vance 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!

The BENNING CFlex 2 may be used only in electrical circuits of over voltage
category IV with a maximum voltage of 600 V or of over voltage category III
with a maximum voltage of 1000 V between the conductor and ground.
Remember that work on electrical components of all kinds is dangerous. Even
low-voltages of 30 V AC and 60 V DC may be dangerous to human life.
Before starting the unit, always check it as well as all measuring lead and
wires for signs of damage.
Should it appear that safe operation of the unit is no longer possible, it should be shut down
immediately and secured to prevent that it is switched on accidentally.
It may be assumed that safe operation is no longer possible:
- if the device or the measuring lead exhibit visible damages,
- if the unit no longer works,
- after long periods of storage under unfavourable conditions,
- after being subject to rough transportation, or
- if the device or the measuring lead are exposed to moisture.
3. Scope of delivery
The scope of delivery for the BENNING CFlex 2 comprises:
3.1 One BENNING CFlex 2,
3.2 One compact protective pouch,
3.3 Two 1.5 V batteries of type AAA (IEC LR 03)
3.4 One operating manual
4. Description of AC current transformer
The BENNING CFlex 2 is a flexible digital TRUE-RMS AC current transformer for measuring
AC currents of up to 3000 A.
See figure 1: Appliance front face
The display and operator control elements specified in Fig. 1 are designated as follows:
Flexible measuring loop, for clamping the single-wire AC current-carrying (live) conductor
Closing mechanism of the measuring loop
Rotary switch, for selecting the measuring ranges
HOLD button, storage of the indicated measured value,
MIN/MAX button, storage of the highest and lowest measured values
6Illumination key, activates the display illumination for approx. 30 seconds
7 Digital display, for displaying the measured value and range exceedance,
8Battery compartment cover
5. General information
5.1 General details on the AC current transformer
5.1.1 The digital display 7is a 4-digit liquid crystal display with 13 mm high numerals, com-
plete with decimal point. The largest numerical value which can be displayed is 3150.
5.1.2 In case of a range exceedance (overflow), “-0.L-” is displayed.
Warning, no indication and prior warning in the event of an overload condition!
5.1.3 The rotary switch is intended for selecting the measuring ranges of 30 A, 300 A and
3000 A AC.
5.1.4 HOLD key function: The measuring result can be stored by pressing the HOLD key .
The “HOLD” symbol simultaneously appears on the display 7. Press the key again to
switch the device back to measuring mode.
5.1.5 The MIN / MAX key function automatically records and stores the highest and the

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lowest measured value. By pressing the key, the following values are displayed: “MAX”
shows the highest value stored, “MIN” shows the lowest value stored and “MIN/MAX”
shows the current measured value. Press the key for approx. 2 seconds to switch the
device back to normal operating mode.
5.1.6 The illumination key 6activates the illumination of the display 7. It is switched off by
pressing the key again or automatically after approx. 30 seconds.
5.1.7 The measuring rate of the BENNING CFlex 2 amounts nominally to 2 measurements
per second for the digital display.
5.1.8 The BENNING CFlex 2 is switched on and off with the rotary switch . Shutdown posi-
tion “OFF”.
5.1.9 The BENNING CFlex 2 switches off automatically after approx. 15 minutes (APO,
Auto-Power-Off is activated, if the symbol is shown on the display 7). It switches
on again, if the HOLD key or another key is actuated. Automatic switch-off can be
deactivated by pressing the HOLD key and by simultaneously switching on the
BENNING CFlex 2 from the switching position “OFF”. The symbol disappears from
the display 7.
5.1.10 The BENNING CFlex 2 is supplied by two 1.5 V batteries (IEC LR03/ AAA/ micro).
5.1.11 If the battery voltage drops below the specified operating voltage of the
BENNING CFlex 2, then a battery symbol appears in the display 7.
5.1.12 The battery life is approx. 120 hours (alkaline battery).
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 Length of the measuring loop: approx. 46 cm
5.1.15 Cable diameter of the measuring loop: approx. 8.5 mm
5.1.16 Cable length from measuring loop to housing: approx. 1.8 m
5.1.17 Housing dimensions: (L x W x H) = 120 x 70 x 26 mm
5.1.18 Weight of the device: 286 g
6. Ambient conditions
- The BENNING CFlex 2 is intended for making measurements in dry environment.
- Maximum barometric elevation for making measurements: 2000 m,
- Overvoltage category: IEC 60664/ IEC 61010 → 600 V category IV, 1000 V category III
- Contamination class: 2 (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 80 %, non-
condensing
- Storage temperature: The BENNING CFlex 2 can be stored at temperatures between - 10
°C and + 60 °C, at a relative air humidity lower than 70 % without batteries.
7. Electrical specifications
Note: The measuring precision is specified as the sum of
- a relative fraction of the measured value and
- a number of digits (counting steps of the least significant digit).
This specified measuring precision is valid for temperatures in the range from 23 °C ± 5 °C and
relative humidity less than 80 %.
7.1 Alternating current ranges
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 < 1.6 up to 100 % of the final measuring range value
Crest factor < 3.2 up to 50 % of the final measuring range value
Measuring Range Resolution Meas. precision* within
the frequency range 45 Hz - 500 Hz protection Overload
30 A 10 mA ± (3.0 % of the measuring value + 5 digit) 3000 A
300 A 100 mA ± (3.0 % of the measuring value + 5 digit) 3000 A
3000 A 1 A ± (3.0 % of the measuring value + 5 digit) 3000 A
* The measuring accuracy is specified for a sinusoidal curve. The stated accuracy is specified
for conductors that are centrally clamped by means of the measuring loop (see figure 3).
For conductors that are not centrally clamped, an additional error has to be considered.

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Distance from the middle Positioning error
25 mm ± (1.0 % of the final measuring range value)
50 mm ± (2.0 % of the final measuring range value)
75 mm ± (3.0 % of the final measuring range value)
8. Measuring with the BENNING CFlex 2
8.1 Preparing the measurement
Operate and store the BENNING CFlex 2 at the specified storage and operating temperatures
only! Do not permanently expose the device to sunlight.
- Nominal voltage and nominal current of the enclosed safety measuring lead comply with the
respective values of the BENNING CFlex 2. The safety measuring lead is firmly connected
with the BENNING CFlex 2 and is not detachable.
- Check the insulation of the safety measuring lead. If the insulation is damaged, the
BENNING CFlex 2 must be scrapped immediately.
- Strong sources of interference in the vicinity of the BENNING CFlex 2 might involve unsta-
ble readings and measuring errors.
Do not exceed the maximum permitted voltage with respect to earth potential!
Electrical danger!
The highest voltage that may be applied to the BENNING CFlex 2 with respect to earth potential
is 600 V CAT IV / 1000 V CAT III.
8.2 AC current measurement
- Select the measuring range (30 A, 300 A or 3000 A) by means of the rotary switch .
- Clamp the single-wire live conductor centrally by means of the flexible measuring loop .
- Read the measured value from the digital display 7.
See Figure 2 a: Alternating current measurement
See Figure 2 b: Alternating current measurement
9. Maintenance
Before opening the BENNING CFlex 2, make sure that it is free of voltage!
Electrical danger!
Work on the opened BENNING CFlex 2 under voltage may be carried out only by skilled elec-
tricians with special precautions for the prevention of accidents.
Make sure that the BENNING CFlex 2 is free of voltage as described below before opening
the instrument:
- First, remove the BENNING CFlex 2 from the object to be measured.
The BENNING CFlex 2 AC current transformer is not equipped with a fuse.
9.1 Securing the instrument
Under certain circumstances safe operation of the BENNING CFlex 2 is no longer ensured, for
example in the case of:
- Visible damage of the casing.
- Incorrect measurement results.
- Recognisable consequences of prolonged storage under improper conditions.
- Recognisable consequences of extraordinary transportation stress.
In such cases, immediately disconnect the BENNING CFlex 2 from the measuring point and
secure it against further use.
9.2 Cleaning
Clean the exterior of the housing with a clean dry cloth (exception: special cleaning wipers). Avoid
using solvents and/ or scouring agents for cleaning the instrument. It is important to make sure
that the battery compartment and battery contacts are not contaminated by leaking electrolyte.
If electrolyte contamination or white deposits occur in the area of the batteries or battery com-
partment, clean them too with a dry cloth.
9.3 Battery replacement
Before opening the BENNING CFlex 2, make sure that it is free of voltage!
Electrical danger!

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The BENNING CFlex 2 is supplied by means of two 1.5 V batteries of type AAA (IEC LR03).
Battery replacement (see figure 4) is required, if the battery symbol appears on the display 7.
Proceed as follows to replace the batteries:
- Remove the BENNING CFlex 2 from the object to be measured.
- Switch the rotary switch to position “OFF”.
- Put the BENNING CFlex 2 face down and unscrew the screw of the battery compartment
cover 8.
- Lift off the battery compartment cover (in the area of the housing slots) at the bottom part of
the battery compartment.
- Replace the exhausted batteries by two new ones of type AAA (LR03). Make sure that the
new batteries are inserted with correct polarity!
- Place the battery compartment cover onto the bottom part and tighten the screw.
See figure 4: Battery replacement

Make your contribution to environmental protection!
Do not dispose of discharged batteries in the household garbage. Instead, take
them to a collecting point for discharged batteries and special waste material.
Please inform yourself in your community.
9.4 Calibration
To maintain the specified accuracy of the measurement results, the instrument must be recali-
brated at regular intervals by our factory service. We recommend a recalibration interval of one
year. Send the unit to the following address:
Benning Elektrotechnik & Elektronik GmbH & CO. KG
Service Centre
Robert-Bosch-Str. 20
D - 46397 Bocholt
10. Environmental note
At the end of the product’s useful life, please dispose of the device at collection points
provided in your community.

Benning Elektrotechnik & Elektronik GmbH & Co. KG
Münsterstraße 135 - 137
D - 46397 Bocholt
Telefon ++49 (0) 2871- 93 - 0 • Fax ++49 (0) 2871- 93 - 429
www.benning.de • eMail: [email protected]