new earth testers from megger - states® earth testers from megger paul swinerd 2 megger - earth...
TRANSCRIPT
1
New Earth Testers from Megger
Paul Swinerd
2
Megger - Earth Testing Pioneer
Dr George Tagg pioneered earth testing at Megger
Designing, manufacturing and selling for well over 50 years
3
Days gone by
4
Existing products
Direct 2 terminal & 3 terminal earth electrode testing• DET3TA• DET3TD• DET3TC• DET3/2
2 & 3 terminal and 4 terminal soil resistivity testing• DET5/4D• DET5/4R• DET2/2
Stakeless testers• DET10C-EU and DET20C-EU
5
Products being replaced
DET5/4DDET5/4R
• Last orders plan to be maximum 6 months from release of new products, so June 2007
• This is for sales of products – not support and repair of the products which we plan to continue for a further five years
Why?• DET5/4 has been around for many years, now dated• Although sound design, has basic user interface and
feature set
6
The new family New family to replace DET5/4D and DET5/4R
• DET4TC– 2, 3 and 4 pole ground tester digital display–Selective (ART) and Stakeless test capability
• DET4TCR– As DET4TC but rechargeable
• DET4TC + KIT–Fully kitted with ICLAMP and VCLAMP
• DET4TCR + KIT–Fully kitted with ICLAMP and VCLAMP
7
DET4TC/RExcellent user interfaceFull diagnosticsNew case design
(as DET3TD/TC)Backlit displayARTStakeless testing
8
DET4TC/R + KIT
Fully Kitted optionICLAMPVCLAMPStakeless test calibration loopInstrument calibration check boxRight angle adaptor kit
9
Earth Testing theory
10
Two Basic Test Types
Soil resistivity• Choose location and design for earth system
Earth system resistance• Check resistance low enough
11
Soil Resistivity
Theory
12
Soil Resistivity
Purpose of this test:• Find lowest possible resistance in an area• Obtain the values needed to design the earth system
Factors affecting soil resistivity• Soil composition• Moisture in the ground• Temperature
Consider• Resistivity will vary through the year• Moisture more constant at water table• Stable temperature below the frost line
13
Soil Resistivity test methods
Purpose: Survey a site for the lowest resistance connections for Earth.
Methods: 4-pole (Wenner method).
A A A <A/20
C1 (E) C2 (H)P1 (ES) P2 (S)
Imeas
Emeas
Soil resistivity, ρ = 2πAR (Ωcm)
R = Emeas/Imeas
14
Soil Resistivity test terms
Average soil resistivity, ρ = 2πAR (Ωcm)Variables
• ρ is average soil resistivity to depth A in ohm-cm • A is the distance between the spikes• R is the resistance read from the earth tester
For example• Planning to install 3m long electrodes?• Then measure soil resistivity with spacing, A, between
spikes at 3m• The depth of test probes should be less than 3/20 = <15cm
15
Soil Resistivity test terms
Soil resistivity is of interest because by rearranging the formula and knowing its value from tables we can calculate the resistance of the earth electrode required.
ρ = 2πAR (Ωcm) therefore electrode resistance R = ρ / 2πA
16
Earth System Resistance
Theory
17
But First
Earth system definitionsWhy test?Component parts of earth electrode resistance
18
Earth system definitions
Simple• Generally consists of a single ground electrode driven into
the ground
Complex• Multiple ground rods connected, mesh or grid networks
– More common in sub stations, cell sites etc
19
Why test earth system?
Why a low earth resistance is required:• Enable protective devices to operate in good time• Reduce ground potential rises (GPR)• Danger of shock from GPR (during fault)
– Step potential– Touch potential– Adjacent conductors
20
Step and touch voltages
V V
Step Touch
21
Resistance and GPR from earth electrode
0.0
0.4
0.8
1.2
1.6
2.0R
esis
tanc
e (O
hms)
0
200
400
600
800
1000
Volta
ge (V
)
Resistance GPR
22
Component parts of earth electrode resistance
1 – Resistance of the electrode and the connections to it 2 – Contact resistance of the surrounding soil to the electrode 3 – Resistance of the surrounding body of earth around the electrode – these can be thought of as “shells” and create a sphere of influencesphere of influence
23
Earthing System Resistance - theory
Purpose: Measure resistance of earthing system to Earth - ascertain that prospective fault current can be conducted safely to Earth and thus limit “touch voltage”.Methods:
• 2-pole: Direct measurement.• 3-pole: Fall of Potential – Full method• 3-pole: Fall of Potential – short method• 3-pole: Slope Method.• Selective measurements: ART• Stakeless measurements: Earth Clamp.
24
2-pole: Direct measurement
Measure “coupling” between two earth points; measure resistance of earth electrode to Earth.
C1 (E)C2 (H)P1 (ES)P2 (S)Imeas
Emeas
Earth electrode under test
Second earth electrode or other low resistance, conductive connection to Earth.
Measures resistance of the two Earth electrodes in series.
R = Emeas/Imeas
25
2-pole: Direct measurement disadvantages
A series measurement of a resistance loop.Accuracy depends on assumption that all other elements in loop are of low resistance.Must disconnect individual ground electrodes to measure them.
26
3-pole: Fall of Potential (full method)
Classic method for measuring resistance of a single earthing electrode, or of a system of electrodes to Earth.
A
B
C2 (H)P2 (S)
C1 (E)P1 (ES)
Imeas
Emeas
Earth electrode under test
Auxiliary test electrodes
R = Emeas/Imeas
27
Fall of Potential - Full Method
Vary location of P2 (Potential) spike by regular steps along a straight line between the electrode under test and the C2 (Current) electrode.Plot graph of resistance measurements to distance of PResistance of system taken where slope is flat.Note: The C spike must be outside the sphere of influence to achieve a viable reading
28
Fall of potential - Current Probe Sphere of Influence
AuxiliaryCurrent
Probe (C)
AuxiliaryPotentialProbe (P)
GroundElectrode
Under Test (X)
P probe must be outside of both spheres of influence for correct measurement
29
Fall of potential – test and result
CurrentProbe
Position
Distance of Potential Probe from X (dp)Ground
ElectrodePosition
X C
Res
ista
nce
in O
hms
CurrentProbe (C)
PotentialProbe (P)Positions
GroundElectrode
Under Test (X)
30
Fall of potential – test and result
CurrentProbe
Position
Distance of Potential Probe from X (dp)Ground
ElectrodePosition
X C
Res
ista
nce
in O
hms
CurrentProbe (C)
PotentialProbe (P)Positions
GroundElectrode
Under Test (X)
31
Fall of potential – test and result
CurrentProbe
Position
Distance of Potential Probe from X (dp)Ground
ElectrodePosition
X C
Res
ista
nce
in O
hms
CurrentProbe (C)
PotentialProbe (P)Positions
GroundElectrode
Under Test (X)
32
Fall of potential – test and result
CurrentProbe
Position
Distance of Potential Probe from X (dp)Ground
ElectrodePosition
X C
Res
ista
nce
in O
hms
CurrentProbe (C)
PotentialProbe (P)Positions
GroundElectrode
Under Test (X)
33
Fall of potential – test and result
CurrentProbe
Position
Distance of Potential Probe from X (dp)Ground
ElectrodePosition
X C
Res
ista
nce
in O
hms
CurrentProbe (C)
PotentialProbe (P)Positions
GroundElectrode
Under Test (X)
34
Fall of potential – test and result
CurrentProbe
Position
Distance of Potential Probe from X (dp)Ground
ElectrodePosition
X C
Res
ista
nce
in O
hms
CurrentProbe (C)
PotentialProbe (P)Positions
GroundElectrode
Under Test (X)
35
Fall of potential – test and result
CurrentProbe
Position
Distance of Potential Probe from X (dp)Ground
ElectrodePosition
X C
Res
ista
nce
in O
hms
CurrentProbe (C)
PotentialProbe (P)Positions
GroundElectrode
Under Test (X)
36
Fall of potential – test and result
CurrentProbe
Position
Distance of Potential Probe from X (dp)Ground
ElectrodePosition
X C
Res
ista
nce
in O
hms
CurrentProbe (C)
PotentialProbe (P)Positions
GroundElectrode
Under Test (X)
37
Fall of potential – test and result
CurrentProbe
Position
Distance of Potential Probe from X (dp)Ground
ElectrodePosition
X C
Res
ista
nce
in O
hms
CurrentProbe (C)
PotentialProbe (P)Positions
GroundElectrode
Under Test (X)
38
Fall of potential – test and result
CurrentProbe
Position
Distance of Potential Probe from X (dp)Ground
ElectrodePosition
X C
Res
ista
nce
in O
hms
CurrentProbe (C)
PotentialProbe (P)Positions
GroundElectrode
Under Test (X)
39
Fall of potential – test and result
CurrentProbe
Position
Distance of Potential Probe from X (dp)Ground
ElectrodePosition
X C
Res
ista
nce
in O
hms
CurrentProbe (C)
PotentialProbe (P)Positions
GroundElectrode
Under Test (X)
40
Fall of potential – test and result
CurrentProbe
Position
Distance of Potential Probe from X (dp)Ground
ElectrodePosition
X C
Res
ista
nce
in O
hms
CurrentProbe (C)
PotentialProbe (P)Positions
GroundElectrode
Under Test (X)
41
Fall of potential – test and result
CurrentProbe
Position
Distance of Potential Probe from X (dp)Ground
ElectrodePosition
X C
Res
ista
nce
in O
hms
CurrentProbe (C)
PotentialProbe (P)Position
GroundElectrode
Under Test (X)
True system resistance measured here
42
Fall of potential – test and result
CurrentProbe
Position
Distance of Potential Probe from X (dp)Ground
ElectrodePosition
X C
Res
ista
nce
in O
hms
CurrentProbe (C)
PotentialProbe (P)Position
GroundElectrode
Under Test (X)
True system resistance measured here
Usually approx 62% of X to C distance
43
Typical Probe Spacing
Single electrode• C probe 15m away• P probe 9.5m away
Large system, several electrodes or plates• C probe 60m away• P probe 38m away
Above only rough guide – look up tables available
44
Fall of Potential Method – Disadvantages
Extremely time consuming and labour intensive.- Temporary probes must be placed.- Cables must be run to make connections.
Space constraints can make it hard to place remote probes. (probes usually many meters away)Must disconnect individual ground electrodes to measure them.
45
3-pole: Fall of Potential (short method)
Reduced method based on fewer measurements, saving time
Earth electrode
under test
B
C2 (H)P2 (S)
Emeas
C1 (E)
P1 (ES)
Imeas
0.62B
Auxiliary test electrodes
R = Emeas/Imeas
46
3-pole: Fall of Potential (short method)
Site P2 (Potential) spike at 62% of B and take resistance measurement.Locate P2 ± 0.1B around the 62% point and take additional resistance readings, Rb and Rc.If the three readings are within an agreed accuracy limit, the system resistance is the average
47
Fall of Potential Method (short method)–Disadvantages
Not as accurate as less measurements are madeSpace constraints can make it hard to place remote probes.Must disconnect individual ground electrodes to measure them
48
3-pole: Slope Method
Alternative method applicable for physically constrained sites.
B
C1 (E) C2 (H)
P1 (ES)
P2 (S)
Imeas
Emeas
Earth electrode
under test
0.4B
0.6B
0.2B
Auxiliary test electrodes
R = Emeas/Imeas
Distance to C probe (B) Now 2 to 3 times the maximum dimension of earth system.
49
3-Pole: slope method
Distance of Potential Probe from X (dp)
Res
ista
nce
in O
hms
CurrentProbe (C)
PotentialProbe (P)
GroundElectrode
Under Test (X)
No flat area
50
3-pole: Slope Method
Vary location of P2 (Potential) spike by regular steps along a straight line between the electrode under test and the C2 (Current) electrodeMeasure resistance at each step and plot a graph of R versus distance.Measure resistance at 0.2B, 0.4B and 0.6B: R1, R2 and R3.Slope coefficient, m=(R3-R2)/(R2-R1) relates distance B and ideal distance of the voltage spike (P2) for measuring the resistance.
51
3-pole: Slope Method
Measure R1 at 20% distance to C2
C2 (H)
Earth electrode
under test
B
C1 (E)
P1 (ES)
Imeas
Emeas
0.2B
R1
C2 (H)
μ=(R3-R2)/(R2-R1)
R1= 9.3 ohm
R = Emeas/Imeasμ = (R3-R2) / (R2 – 9.3)
52
3-pole: Slope Method
Measure R2 at 40% distance to C2
C2 (H)
Earth electrode
under test
B
C1 (E)
P1 (ES)
Imeas
Emeas
0.4BR2
C2 (H)
μ=(R3-R2)/(R2-R1)
R1= 9.3 ohmR2= 16 ohm
R = Emeas/Imeasμ = (R3– 16) / (16 – 9.3)
53
3-pole: Slope Method
Measure R3 at 60% distance to C2
C2 (H)
Earth electrode
under test
B
C1 (E)
P1 (ES)
Imeas
Emeas
R30.6B
C2 (H)
μ=(R3-R2)/(R2-R1)
μ = (19.2 – 16) / (16 – 9.3)
R1= 9.3 ohmR2= 16 ohmR3= 19.2 ohm
R = Emeas/Imeas
54
3-pole: Slope Method
Calculate value of μ
C2 (H)
Earth electrode
under test
B
P2 (S)C1 (E)
P1 (ES)
Imeas
Emeas
0.4B
0.6B
0.2B
Auxiliary test electrodesR3R2R1
C2 (H)C2 (H)
μ=(R3-R2)/(R2-R1)
R = Emeas/Imeasμ = (19.2 – 16) / (16 – 9.3)
μ =0.478
55
3-pole: Slope Method
Tables of values for the co-efficient of slope against actual P spike distance is published in the instrument user guide.Take calculated value of m and look up ideal distance of the voltage spike (P2) for measuring the electrode resistance
56
3-pole: Slope Methodμ =0.478
57
3-pole: Slope Method
Measure electrode resistance at 0.632B
Earth electrode
under test
C2 (H)
B
C1 (E)
P1 (ES)
P2 (S)
Imeas
Emeas
0.632B
Auxiliary test electrodes
C2 (H)C2 (H)
R = Emeas/Imeas
58
3-pole: Slope Method - Disadvantages
Less accurate than the full fall of potentialRequires mathsMust disconnect individual ground electrodes to measure them
59
Selective Measurements ‘ART’
Attached Rod Technique No need for the earth electrode to be disconnectedUses current clamp ‘ICLAMP’ to measure current flowing in electrode under test.
60
Application of ART
Potential Probe (P) CurrentProbe (C)
GroundElectrodes
Building earthconnection/s I Total
I System
Ie1
Ie 2Ie 3 Ie test Test
Ie Test > I Total20
X Connection
61
ART with 4 pole measurement
Potential Probe (P) CurrentProbe (C)
GroundElectrodes
Under Test (X)
Building earth connection/s
I TotalI System
Ie 1 Ie 2Ie 3Ie Test
C1 and P1 connections
62
Effects of Earth Coupling
X Test point
C P P
X Test point
C
Result – Clamp low symbol or unexpected high reading
Answer use 3 pole method – disconnect electrode
63
Misuses – Telecom Guy Lines
Current CPotential P
X Connection
We MUST fully understand the test current path
64
The Best Application of ART
Field of earth / Earth FarmsPole mounted transformersDomestic TT (earth electrode) systemsSingle guy lines on towers (isolated)Lightning protection electrodes
65
Measuring Earth Leakage Current
Building earth connection/s
System leakage current
Ie 1 Ie 2Ie 3 Ie 4 leakage (mA)DET4TC set to A range
Using ICLAMP to measure electrode leakage current
66
“Stakeless” MeasurementsNo need for the earth electrode to be disconnectedNo need for test spikes to be used
67
Clamp-On / Stakeless Methodology
Inject a voltage and measure the resultant current produced in a ground loop.Requires a complete electrical circuit to measure.Measures the complete resistance of the path (loop) the signal is taking.In a multiple ground system the circuit can be considered a loop comprising:- The individual ground electrode.- A return path via all other electrodes.- The mass of earth.
68
Clamp-On / Stakeless Methodology
In a multiple ground system the circuit can be considered a loop comprising:- The individual ground electrode.- A return path via all other electrodes.- The mass of earth.The single electrode will have a higher resistance than the remainder of grounds connected in parallel.Inject a voltage and measure the resultant current produced in a “single turn” ground loop.
69
Clamp-On / Stakeless Methodology
GroundElectrode
Under Test
Building earth connection/s
ICLAMP
VCLAMP
70
Clamp-On / Stakeless Methodology
ICLAMP
VCLAMP
R testR1R2R3R425 Ohms 22 Ohms 19 Ohms 25 Ohms 45 Ohms
R Meas.= 50.6 Ohms
R Meas. = R test + 1 / (1/R1 + 1/R2 + 1/R3 + 1/R4)
71
Clamp-On/Stakeless Methodology
For 6 similar electrodes each with a resistance of 10Ω
• Rloop = 10Ω + 2Ω = 12Ω reading on DET4TC/R
For 60 similar electrodes with a resistance of 10Ω• Rloop = 10Ω + 0.17Ω = 10.17Ω reading on DET4TC/R
The more electrodes the more accurate the reading
72
Clamp-On /Stakeless Method - Advantages
Test is quick and easy• No disconnecting the ground rod from the system.• No probes need to be driven/cables connected.
Includes the bonding and overall connection resistance• Not available with Fall of Potential
Can measure the leakage current flowing through the system.
.
73
Clamp-On /Stakeless Method - Disadvantages
Effective only in situations with multiple grounds in parallel (pole grounds).Cannot be used on isolated grounds (no return path)
• Not applicable for installation checks/commissioning new sitesCannot be used if an alternate lower resistance return exists not involving the soil
• Cellular towers• Substations
Subject to influence if another part of the ground system is in “resistance area”
• Result will be lower than true resistance.Test is carried out at a high frequency (enables the transformers to be small)
• Less representative of a fault at power frequency but easier to filter out noise
74
Requires a good return path• Poor return path may give high readings.
Connection must be on the correct part of the loop for the electrode under test
• Requires thorough understanding of the system• Wrong connection can give a faulty result.
Susceptible to noise from nearby substations and transformers (no reading).No basis for the test in standards – no objective reference for the test resultsLess effective for very “low” grounds• Extraneous elements in reading become comparatively large.
Clamp-On /Stakeless Method - Disadvantages
75
Applications – Service Entrance/Meter
GroundRods
ServiceBox
Pole-MountedTransformer
ServiceMeter
76
Applications – Lightning Protection
Removable links(Jug handles)
Link removed for2 pole measurement
Lightning protection tape
Normal 2 Pole method
77
Applications – Lightning Protection
Removable links(Jug handles)
ICLAMP and VCLAMP
Lightning protection tape
Using ‘Stakeless’ method no need to remove link
78
SubstationGrounded Perimeter
Fence
E
Clamp-OnGroundTester
Substation Ground System
TestCurrent
Misuses – Substations
79
Misuses – Lightning ProtectionTest current flowing around loopOf lighting protection tape.
Lightning protection tape
80
The Best Application of “Stakeless” Testing
Field of earth / earth farmsPole Mounted transformer electrodesPole mounted transformer guy line when connected to earth systemEarthing in Sub-station cable cellars
• It is often impossible to drive in test spikes so this is an ideal application for stakeless measurements
Single guy lines on towersLightning protection electrodes
81
DET4TC/R
82
New product common philosophy
Intuitive to useOne button operationAutomatic checking to avoid mistakes and poor connections, indicated on displayComplete and ready to start testing kit, including calibration certificateCompetitively priced to sell, including distributionCombination of features, benefits and price makes these ground testers the most attractive on the market
83
New product common features
Like DET3TD, based on building wiring housing Delivered in plastic carry caseIncludes stake and wire kit with each modelHigh quality large and easy to read backlit LCDIncludes batteriesHas quick start guide on the lidEasy to use wearing glovesComes with calibration certificate as standardThree year warrantyAvoids language variants for easy stock holding
84
Basic specification – DET4TC/R2 terminal test, no links required 3 terminal earth electrode test, no link required4 terminal Resistivity test to 20k OhmsART (Attached Rod Technique)‘Stakeless’ measurementsEarth voltage measurementEarth leakage current measurement (with ICLAMP)Automatic checking of
• Current spike resistance• Voltage spike resistance• Earth noise voltage• Blown fuse• Battery status
Rechargeable batteries on DET4TCR
85
DET4TC/R specifications - electrical
Resistance range (2,3 & 4 pole): 0.01 to 20kΩMaximum P & C spike resistance: 100kΩ (50V output)ART range: 0.01 to 20kΩStakeless range: 0.01 to 200ΩEarth voltage range: 0 – 100VEarth current range (DET4TC/R + ICLAMP): 0.5mA to 19.9ATest frequency: 128 HzTest voltage: 25V or 50V selectable (Factory set 50V)Earth noise rejection: 40V peak to peakBattery type: 8 off AA cells or rechargeableApproximate battery life: 700 consecutive testsSafety: EN61010-1 CATIV 100VEMC: EN61326-1:1998 heavy industrial
86
Common specifications - Mechanical
IP54Terminals: 4mm plug typeDimensions: 203 x 148 x 78mmWeight: 1kgOperating temperature range: -15 to 55°CStorage temperature range: -40 to 70°CHumidity: 95% RH non-condensing at 40°C
87
DET4TC/R Accessories
Standard• Hard carry case• Stake and wire kit (15m, 10m, 10m, and 3m)• External AC/DC adaptor – interchangeable plugs
Optional• ICLAMP• VCLAMP (includes calibration check pcb)• Calibration check box – 6220-824• Right angled terminal adaptor set – 6220-803• Black crocodile clip - 6220-850• Vehicle 12V charger lead – 6280-375
88
DET4TC/R + KIT Accessories
Standard• Hard carry case• Stake and wire kit (15m, 10m, 10m, and 3m)• External AC/DC adaptor – interchangeable plugs• ICLAMP• VCLAMP (includes calibration check pcb)• Calibration check box – 6220-824• Right angled terminal adaptor set – 6220-803
Optional• Black crocodile clip - 6220-850• Vehicle 12V charger lead –
89
Accessories – terminal adaptor set
90
DET4TC/R Competitors
91
4620/30 / CA 6460/2• Disadvantages
– 42V output only– P and C high ind. combined– No cal. Cert.– IP50– No leads or case etc. std.– Only 2kΩ range– Links required
• Advantages– However many lead kit
options
DET4TC/R• Advantages
– Superior noise rejection– CATIV 100V– Much lighter– ART and Selective
capability– Earth leakage current
range– Earth voltage range– Superior diagnostics
AEMC / Chauvin Arnoux
92
AEMC / Chauvin Arnoux6470
• Advantages– 2 & 4 pole DC bond check– 0 – 100kΩ range– 16 or 32V output– Auto frequency control– 50Hz earth resistance test– Wenner method rho calc.– Schlumburger method rho
calc.– Memory for 512 tests– Software supplied
• Disadvantages– IP54 but only with lid closed– Rechargeable only
DET4TC/R• Advantages
– ART & Stakeless capability
– 25 or 50V output– 128Hz only– Much lighter– Easy to use– Hard carry case
93
Fluke1623 (Saturn Geo Plus)
• advantages– Battery life 3000 tests– 125 or 128Hz– 2 years warranty– ART noise current
rejection better at 3A– Stakeless noise current
rejection better at 10A <20Ω
• Disadvantages– IP54 but battery door IP40– Only CAT II, 300V rated– Only supplied with 2 leads
DET4TC/R• Advantages
– Full diagnostics– Superior temp specs.– Superior noise rejection– 25 and 50V output– No links required– Ground voltage range– Ground current range– Better ART accuracy– 12V charging– Much easier to use– Competitive price
94
Fluke1625 (Saturn Geo X)
• Advantages– ART noise current
rejection better at 3A– Stakeless noise current
rejection better at 10A <20Ω
– Battery life 3000 tests– Automatic frequency
control– DC continuity with buzzer– Test lead compensation– Display resolution 0.001Ω
• Disadvantages– IP54 but battery door IP40
DET4TC/R• Advantages
– CATIV 100V– Superior temp specs.– Superior noise rejection– Much easier to use– Free cal. Cert.– Competitive price
95
MetrelM2124C
• Advantages– 2 pole DC bond check– Wenner method rho
calc.– 125 or 128Hz– Result memory– Output to PC
• Disadvantages– Large 30cm required
between clamps– Many accuracies not
specified
DET4TC/R• Advantages
– Better quality– Accuracy– 25 and 50V output– Back lit display– Superior noise rejection– Superior temp specs.– Ground voltage range
96
Features and Benefits
Tough rubber armoured IP54 rated instrument case• Instrument will last a long time, and will be ready to test
when required
Supplied in tough blow moulded carry case• Helps prevent loss of accessories, also makes ideal ‘tray’
to put the instrument on when testing. Saves having to lay the instrument directly onto muddy ground.
Supplied with calibration certificate, test leads and spike kit
• Saves time having to source separate leads and spikes. No waiting for calibration to be carried out. No hidden costs. Convenient.
97
Features and Benefits
‘Attached Rod Technique’ capability, ART• Saves both time and aggravation having to undo rusted
connections. No need to shut down supply to ensure safety
‘Stakeless’ testing capability• Allows testing in areas when driving test spike is
impossible. E.g. Sub station cable cellars, or when testing lightning protection in concreted locations
One button operation with automatic noise check and automatic P and C spike resistance check
• Little time required learning operation, and time saved not having to spend considerable time troubleshooting poor connections etc.
98
Features and Benefits
User selectable output voltage – 25V or 50V• The ability to test in agricultural locations as per
IEC61557-5. 25V will not harm livestock
40V Pk to Pk Noise rejection• Can be used in most locations with ground noise such as
sub-stations, near transformers etc.
Back light• Easier to operate when not having to use a torch to be
able to read the display
99
Potential Customers
Existing DET5/4 customersPetro-chemical companiesUtilities, MaintenanceRailwaysRepair Organisations (Industrials), Telecoms and Datacoms installers Specialist grounding/earthing companies and consultantsService providersInsurance companies
100
Available?
New family in stock Dover from January LaunchDET5/4
• Declare intention to be made obsolete June 2007• Last orders accepted June 2007• Repaired and calibrated for a further 5 years.