Ohmmètre de terre et de résistivitéOhmmètre de terre et de résistivité
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Ohmmètre de terre et de résistivité
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Ohmmètre de terre et de résistivitéOhmmètre de terre et de résistivité
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EarEar
th & Resistivity th & Resistivity
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Ear
th & Resistivity
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EarEar
th & Resistivity th & Resistivity
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ErEr
dungs- und Bodenwiderdungs- und Bodenwider
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Er
dungs- und Bodenwider
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ErEr
dungs- und Bodenwiderdungs- und Bodenwider
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OhmmetrOhmmetr
■
Ohmmetr
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OhmmetrOhmmetr
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ÓhmetrÓhmetr
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■■
o de tierra y de resistividado de tierra y de resistividad
Óhmetr
o de tierra y de resistividad
ÓhmetrÓhmetr
o de tierra y de resistividado de tierra y de resistividad
o di terra e di resistivitào di terra e di resistività
o di terra e di resistività
o di terra e di resistivitào di terra e di resistività
OhmmeterOhmmeter
Ohmmeter
OhmmeterOhmmeter
standsmesserstandsmesser
standsmesser
standsmesserstandsmesser
C.A 6460C.A 6460
C.A 6460
C.A 6460C.A 6460
C.A 6462C.A 6462
C.A 6462
C.A 6462C.A 6462
ENGLISH
User's manual
1
English
Meaning of symbol
Caution! Please consult the User Manual before using the device.
In this User Manual, failure to follow or carry out instructions
preceded by this symbol may result in personal injury or damage
to the device and the installations.
Meaning of symbol
This appliance is protected by double insulation or reinforced
insulation. It does not have to be connected to an earth protection
terminal for electrical safety .
Thank you for purchasing this C.A. 6460 or C.A. 6462 ohmmeter
for earth and resistivity measurement.
To obtain the best possible service from your instrument:
n read this operation manual carefully
n comply with the precautions for use.
PRECAUTIONS FOR USE
n Comply with the conditions for use: temperature, humidity,
pollution level.
n This instrument can be used on category III installations:
Category III meets severe reliability and availability
requirements, corresponding to permanent use on fixed
industrial installations (see IEC 664-1 Ed. 92).
n Only use the instruments on installations that are not live.
n T o prev ent the using mistakenly touching the terminal linked
to the mains electricity supply, you are advised to check
the voltage on the sockets bef ore connecting the instrument.
n Do not perform any measurements when the leads are
connected and the instrument’s buzzer is sounding.
n Check that all the terminals are disconnected before
replacing the fuse or the batteries (C.A 6460).
n Recharge the battery in accordance with the mains voltage
(C.A 6462).
n Make sure that you replace the battery pack (C.A 6462)
with an appropriate battery pack.
n Respect the value and type of the fuse to avoid damaging
7. TO ORDER ............................................................................. 35
20
1. PRESENTATION
The C.A 6460 and C.A 6462 are ohmmeters equipped with
digital displays for earth and resistivity measurements in the
field.
They are particularly well-adapted to use in difficult conditions,
in the presence of interference voltages, high earth currents
or highly resistive auxiliary connections, in accordance with
standards NF EN 61010-1 + A2, NF EN 61557 parts 1 and 5,
NF EN 61326-1 + A1.
For easier handling, the instrument is equipped with:
■ a single pushbutton for activation of measurement,
■ an automatic switching system f or the measurement calibre,
■ a large-size backlit liquid crystal display,
■ three LEDs indicating the presence of faults which may
invalidate the measurement result,
■ four coloured screw terminals to simplify connection of the
leads,
■ a captive connection strap.
2. DESCRIPTION
➀
➁
➂➃
➄➅
21
➀ Four measurement terminals marked E (X), ES (Xv), S
(Y) and H (Z)
➁ Mains socket equipped with a cover to protect it from
dust (only on C.A 6462).
Battery charge LED (only on C.A 6462); when it is lit
continuously , it indicates that the battery is being charged.
It changes colour when charging has finished.
➂ LCD display with backlighting which lights up whenever
the ➄ pushbutton is pressed.
The liquid crystal display includes the digital display of
the measured values, the related units and symbols. The
“minus” sign indicates reversal of the measurement
conditions.
The “1” sign alone on the left of the screen indicates that
the measured resistance is greater than 1999 Ω.
indicates that the power supply is too low to make
a correct measurement.
➃ Fuse holder
➄ Fleeting control measurement pushbutton used for
starting up the equipment and tripping the measurements.
As soon as the pushbutton is released, the equipment is
turned off.
➅ Three indicator lights that flash when the measurement
is not valid (see § 3.5 fault signalling).
- “FAULT” : if the current circuit resistance is too high
- “HIGH RESISTANCE” : means that the measurement
- “HIGH NOISE” : if there is too much interference in the
The equipment is also provided with a cover and a transport
handle.
if the current circuit resistance is too high
if the fuse is defective
is liable to be over-affected by
the resistance in the S.ES
voltage circuit.
S.ES voltage circuit, it means that the
electronics saturated and the
measurement is no longer valid.
22
■■
■ Buzzer
■■
The equipment features a buzzer which buzzes when the
terminals of the equipment are connected to a voltage source.
The sound volume is proportional to the voltage up to
approximately 30 V then becomes stable.
3. USE
3.1Implementation
■ Connect the cords to the equipment using the forked
terminals and in compliance with the terminal colours.
■ Pay out the cords and set the stakes at the ends.
■ Connect the cords to the stakes using the alligator clips.
■ Return to the equipment, press the pushbutton and read
the measurement results.
3.2Earth resistance measurement
To measure the earth resistance, it is advisable to use the
“62%” method (method using two stakes). This measurement
requires the use of the earth Kit components
7 to order).
rod Srod H
(see paragraph
Earth
connection
Turn off the installation power supply and disconnect it
from the earth by opening the ground terminal bar.
1. Short-circuit the terminals E and ES using the
corresponding terminal bar and connect them to the earth
point to be measured.
2. Push rod H as deep as possible into the ground at a
distance “a” from the earth to be measured.
Note: the deeper the earth the greater this distance should
be (larger area of influence). If possible , it is advisable to
have a distance “a” > 25 m
3. Inser t rod S into the ground on a line between the earth
connection E and rod H, at a distance of 62% of “a”.
23
4. Connect the rods to their respective terminals on the
instrument, using the leads.
5. Press the ➄ button until the measurement is displayed.
Make sure that none of the three indicators is flashing,
otherwise check the setup (see § 3.5 Fault signalling)
and start measuring again.
Checking the measurement:
6. Note the measurement value previously obtained.
7. Redo a measurement a few moments later.
8. Move rod S toward H over a distance of 10% of “a”.
Measure and note the result.
9. From the initial position, move the rod S toward E over a
distance of 10% of “a”. Measure and note the result.
If the three measurements are of the same magnitude, the
measurement is correct. Otherwise, increase “a” and start
the entire operation again.
Note: To counter the resistance of the lead E (approximately
22.5 mΩ / m for the lead supplied in the kit), it is better to
disconnect the terminal bar and connect the ES terminal to
the earth to be measured.
Remember to reconnect the earth terminal strip once you
have finished measuring !
3.3Measurement of earth resistivity
This measurement is used for choosing, when possible, the
best location and shape of the earth point before it is built.
This measurement is made using the WENNER method
described below It requires the use of the components of the
resistivity kit
(see para. 7 o order).
rod E
rod ESrod Srod H
1. Check that the terminal bar is disconnected between the
terminals E and ES.
2. Set out the four rods in a straight line at a constant interval “a”,
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3. Connect the rods to their respective terminals on the
instrument, using the leads.
4.
Press the ➄ button until the measurement is displayed.
Make sure that none of the three indicators is flashing,
otherwise check the setup (see § 3.5 Fault signalling) and
start measuring again.
5. Make a note of the measured resistance R.
6. The ground resistivity at point O is obtained by calculation:
ρ = 2π x R x a (with ρ in Ωm, R in Ω and a in metres)
3.4Measurement of coupling
This measurement can be made to determine the coupling
resistance between two earth points. For instance, between
the neutral earth point and the ground earth point (EDF
distribution).
ground earth
point
Cut off the installation power supply and disconnect the
earth points.
1. Open the ter minal bar between the E and ES terminals.
2. Using separate leads, connect the E and ES terminals to
the ground earth point and the H and S terminals to the
neutral earth point.
3.
Press the ➄ button until the measurement is displayed.
Make sure that none of the three indicators is flashing,
otherwise check the setup (see § 3.5 Fault signalling) and
start measuring again.
4. Note the Rmn value displayed.
5. By also measuring Rm (ground earth resistance) and Rn
(neutral earth resistance) using the 62% method described
in § 3.2, the coupling coefficient can be calculated:
Rc
k =
hence
Rc++=
Rm
25
2
neutral earth
point
RmnRnRm
This coupling coefficient k must be < 0.15 (EDF
recommendation)
Remember to reconnect the earth terminal strip once you
have finished measuring !
3.5Fault signalling
■■
■ If the FAULT indicator light flashes:
■■
- either the fuse is defective
- or the circuit is cut off.
- or the rod resistance is too high or the spurious voltage is
excessive.
To check the fuse continuity, shor t circuit the H and E
terminals and make a measurement. If the indicator light
continues to flash, replace the fuse from the front panel
(see para. 5.1.3. Maintenance) If the indicator light no longer
flashes, the fuse is serviceable. You then need to check
the connections.
■■
■ If the HIGH RESISTANCE indicator light flashes: the
■■
resistance in the voltage circuit (between the S and ES
terminals) is too high, or the voltage circuit is cut off. You
then need to check the connections.
■■
■ If the HIGH NOISE indicator light flashes: the spurious
■■
voltage is too high in the voltage circuit In this case, move
the rods because they are in an area where there is too
much interference.
■ If there is interferences and the measurement fluctuates
(and none of the indicator lights is flashing). Measure the
minimum and maximum then calculate the average to obtain
the result.
To be more sure, make two consecutive measurements at
intervals of a few seconds
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4. FUNCTIONAL CHARACTERISTICS
4.1Reference conditions
Influence quantitiesReference values
Temperature23°C ±3 K
Relative humidity45 to 55% HR
Supply voltage9.5 V ±0.2 V
Auxiliary resistances RH, RS, RES and REzero
Spurious voltages (Ac and DC)zero
Serial inductanceszero
Electrical field< 1 V/m
Magnetic field< 40 A/m
4.2Metrological properties
4.2.1Voltage detection
Measurement range: 20 to 250 VAC between the H and E
terminals or between the S and E terminals.
Frequency: DC at 450 Hz
* at the rating consuming most power
The load limit of the power supply is indicated by the display
.
The capacity after this display is approximately 50
measurements of which only 20 are with rechargeable cells.
4.4Environmental parameters
4.4.1Climatic
■■
■ Nominal range of use
■■
- from -10°C to +55°C
- from +20°C to +90 % HR without condensation
■■
■ Storage (without battery or rechargeable cell but with battery
■■
depending on model):
- 40 to +70 °C
- from +20°C to 90 % HR without condensation
■■
■ Climatic conditions:
■■
Reference range
Storage rangeOperating range
90
80
70
60
50
40
30
Relative humidity in % RH
20
10
0
-50
-40 -30 -20 -1001020 3040506070
Temperature in °C
28
4.5Construction specifications
■ Overall dimensions of the unit (L x W x H):
273 x 247 x 127 mm
273 x 280 x 127 mm with handle extended
■ Weight: 2.850 kg (C.A 6460)
3.350 kg (C.A 6462)
4.6Compliance with international standards
■ Electrical safety as per:EN 61010-1 + A2 (ed. 95),
EN 61557 (ed. 97)
■ Dual insulation:
■ Pollution level 2
■ Installation category III
■ maximum operating voltage: 30 V rms
4.6.1. Electromagnetic compatibility
As per NF EN 61326-1, ed. 98)
4.6.2Mechanical protection
The C.A 6460 and 6462 have successfully undergone all the
required mechanical tests (vibration/ rigidity / resistance to
impact / free fall) and therefore meet all the requirements of
the standards NF EN 61557 and NF EN 61010-1.
29
4.6.3Variations in operating range
-Negligib le
(0.% ±0,3 Ω)/10 kΩ(1% ±0.6 Ω)/10 kΩ
(1)
(1)
(2)
Influence quantitiesOperating range limitsTypical measurement variations Maximum measurement variations
T emperature-10 to +55°C(0.% ±1 pt)/10 °C(1% ±1 pt)/10°C
in series with S (50 Hz0 to 13 Vpeak0.2 % ± 1 pt0.5 % ± 2 pt
60 Hz or their harmonicsat 16,67, 50, 60 or 400 Hz
Inductance in series with H and S0 to 13 mH-Negligib le
1) Beyond 3 k
(2) Risk of flashing HIGH RESISTANCE indicator light flashing beyond 4.5 V.
(
30
4.6.4Typical measurements
The following measurements are representative on-site
Common measurement conditions
- Ambient temperature
- 10.5 V power supply voltage
Measurement of three wire ground resistance
- with 5 kΩ in each of the rods H and S,
- with 5 VRMS sinusoidal spurious v oltage at 50 Hz in H and in S,
The error with respect to the real Rx values is less than 4%
±5 pt. (For resistance included between 0 and 20 Ω, the
measurement can be displayed for calibre 2).
Four wire resistitivity measurement
- with 5 kΩ in each of the four rods,
- with 5 Vrms sinusoidal spurious voltage at 50 Hz in H and in S,
The error with respect to the real Rx values is less than 4%
±5 pt. (For resistance included between 0 and 20 Ω, the
measurement will be displayed for calibre 2).
Note: The same measurements with rod resistances of 1 kΩ
instead of 5 kΩ would give an error of less than 1% ±2 pt.
4.6.5Limits
According to NF EN 61557 part 5, free of damage when
connected to 120 % of the network voltage to which it is
assigned. The user must not be e xposed to voltage exceeding
the contact voltage and the protection devices must not
activate.
C.A 6460 and C.A 6462 are designed to operate with the
network de-energised but if wrong manoeuvres are carried
out, the equipment is designed to withstand and overload
applied permanently between any two terminals for: 250 VAC
or 100 VDC, with the possible blowing of the fuse.
31
5. MAINTENANCE
For maintenance, use only specified spare parts. The
manufacturer will not be held responsible for any accident
occuring following a repair done other than by its After
Sales Service or approved repairers.
5.1Servicing
When the symbol is displayed, replace all the
batteries of the CA 6460 or recharge the battery of the CA
6462. Check that no other terminals are connected before
opening the equipment.
5.1.1Replacing the batteries or rechargeable cells
■ Detach the four captive screws under the housing
■ Then remove the shell + front panel assembly of the y ellow
housing
■ Then undo the two screws closing the battery compartment
cover
■ Take out the 8 cells and replace them
Note: It is possible to replace the batteries by rechargeable cells
(1.2 V - 2 Ah or above, NiCd or NiMH, of same size):
■ Remove the plug under the batteries
■ Set the switch to the position: NiCd / NiMH
■ Replace the plug.
■ Insert the 8 rechargeable cells
Then in both cases:
■ Replace the battery cover
■ Undo the two screws closing the battery compartment
cover.
■ Replace the shell + front panel assembly in the yellow
housing then tighten the four captive screws under the
housing
5.1.2Recharging all replacing the battery (C.A. 6462)
■ Connect the battery charge connector to the mains
■ The CHARGE indicator light comes on steadily in red
■ When the battery is charged, the CHARGE indicator light
comes on steadily in green
■ The charge time is approximately six hours f or charging to
80% of the battery capacity. It is possible to top up the
charge.
(C.A 6460 only )
32
- disconnect the mains power cord; the green LED takes
approximately 20 s to go out.
- connect the mains lead again. The charge will resume
and at the end of the second charge, capacity will be
optimum.
■ The charge time is approximately six hours for charging to
80% of the battery capacity. It is possible to top up the charge.
- disconnect the mains power cord; the green LED takes
approximately 20 s to go out.
- connect the mains lead again. The charge will resume
and at the end of the second charge, capacity will be
optimum.
In the event of the unit not being used for some time,
recharge the battery before use.
Note: ½ h charge provides self-sufficiency for one day of
The battery should be replaced by Manumesure or by a
repairer approved by CHAUVIN ARNOUX.
Important: Replacement must be carried out using the model
recommended by CHAUVIN ARNOUX (see § 7. To order)
5.1.3Replacing the fuse
T o check the fuse continuity, short circuit the H and E terminals
and make a measurement. If the FAUL T indicator light flashes,
it means that the fuse has blown.
The fuse is on the front panel.
■ Using a screwdriver, turn the screw through a quarter turn
■ Take out the suppor t containing the fuse
■ Replace the fuse (FF 0.1 A - 250 V – 6.3 x 32 - 30 kA)
■ Replace the support and screw it back.
5.2Cleaning
The instrument must be disconnected from any source
of electricity.
Clean the housing of the equipment Carry out cleaning using
a damp cloth or soapy water. Do not use alcohol, solvents or
hydrocarbons.
5.3Storage
If the C.A 6460 instrument is not used for a long period (more
than two months), remove the batteries and store them
separately.
33
5.4Metrological verification
It is essential that all measuring instruments are regularly
calibrated.
For checking and calibration of your instrument, please contact
our accredited laboratories (list on request) or the Chauvin
Arnoux subsidiary or Agent in your countr y.
Maintenance
Repairs under or out of guarantee: please return the product
to your distributor.
6. WARRANTY
Our guarantee is applicable for twelve months after the date
on which the equipment is made available (extract from our
General Conditions of Sale, available on request).
34
7. T O ORDER
■■
■ C.A 6460 earth and resistivity ohmmeter .... P01.1265.01
■■
Supplied with batteries, this operation manual and a technical
booklet
■■
■ C.A 6462 earth and resistivity ohmmeter .... P01.1265.02
■■
Supplied with batteries, this operation manual and a technical
booklet
Spare parts for C.A 6460 or C.A 6462 :
■■
■ High breaking capacity
■■
fuse 0.1 A - 250 V (set of 10)........................ P01.2970.12
■■
■ Battery 1.5 V alkali LR14 (set of 8) .............. P01.2960.27