Fluke 1520 User manual

September 2000 Rev.2, 2/03
©2000-2003Fluke Corporation. All rights reserved.Printedin USA
All product names are trademarks of their respective companies.
®
1520
MegOhmMeter
Users Manual

i
Table of Contents
Title Page
Unpacking the Meter......................................................................................... 1
Safety Information and Symbols....................................................................... 3
Key functions.................................................................................................... 6
Display.......................................................................................................... 8
Using the Meter ................................................................................................ 10
Connecting to the Circuit Under Test............................................................ 10
Auto-Shut-Off................................................................................................ 12
Measuring Insulation Resistance .................................................................. 12
Measuring Low Resistance........................................................................... 16
Measuring Resistance................................................................................... 18
Measuring Voltage........................................................................................ 18
Checking the Battery..................................................................................... 19
Maintaining the Meter....................................................................................... 20
Cleaning........................................................................................................ 20
Replacing and Disposing of the Batteries...................................................... 21
Testing and Replacing the Fuse.................................................................... 24
Replacement Parts and Optional Accessories.................................................. 27
Principle of Measurement for Resistance.......................................................... 28
Service Centers................................................................................................ 28
Specifications.................................................................................................... 29

ii

ii
List of Tables
Table Title Page
1. Key and Switch Descriptions..................................................................... 6
2. Display Description ................................................................................... 8
List of Figures
Figure Title Page
1. Shipment Content ..................................................................................... 2
2. Display...................................................................................................... 9
3. Connecting to the Circuit Under Test ........................................................ 11
4. Display Example ....................................................................................... 19
5. Replacing the Batteries............................................................................. 23
6. Replacing the Fuse................................................................................... 26

1
Fluke 1520
Unpacking the Meter
The Fluke Model 1520 MegOhmMeter (hereafter, “the meter”) is a handheld instrument
designed primarily to make resistance/insulation resistance measurements.
The MegOhmMeter includes the following items, see Figure 1:
•2 test leads, red and black, 1.5 m
•2 test probes, red and black
•2 alligator clips, red and black
•Hand strap
•Carrying case
•CD ROM (Not Pictured)

Fluke 1520
Users Manual
2
acf02f.eps
Figure 1. Shipment Content

MegOhmMeter
Safety Information and Symbols
3
Safety Information and Symbols
A Caution identifies conditions and actions that may damage the Meter. A W Warning
identifies conditions and actions that pose hazard(s) to the user. International symbols on
the Meter and in the manual are explained below.
YRisk of electric shock JEarth
WSee manual IFuse
TEquipment protected by double or
reinforced Insulation DAC or DC
MBattery Recycling information
Conforms to CSA C22.2 No 1010.1-92 +
Amendment 2 1997, UL 3111 and
ANSI/ISA SP82.01 1994 VDE Conforms to VDE
EN61010 (Pending)
PConforms to EU directives tConforms to UL 3111.1
CAT III
OVERVOLTAGE (Installation) CATEGORY ,,, , Pollution Degree 2 per IEC1010-1
refers to the level of Impulse Withstand Voltage protection provided. Equipment of
OVERVOLTAGE CATEGORY
,,, is equipment in fixed installations (e.g., electricity
meter and primary over-current protection equipment.

Fluke 1520
Users Manual
4
W
Safety Information
Use of instrument in a manner not specified by the manufacturer may impair
safety features/protection provided by the equipment. Read the following safety
information carefully before using or servicing the instrument. To avoid electric
shock or fire, do the following:
•Avoid working alone.
•Inspect the test leads for damaged insulation or exposed metal. Check test
lead continuity. Damaged leads must be replaced. Do not use the Meter if it
looks damaged.
•Be careful when working above 30 V ac rms, 42 V ac peak and
60 V dc. Such voltages pose a shock hazard.
•When using the probes, keep your fingers away from probe contacts. Keep
your fingers behind the finger guards on the probes.
•Measurements can be adversely affected by impedances of additional
operating circuits connected in parallel or by transient currents.
•Verify operation prior to measuring hazardous voltages (voltages above 30 V
ac rms, 42 V ac peak and 60 V dc).

MegOhmMeter
Safety Information and Symbols
5
W
Safety Information (cont.)
•Place test leads in proper input terminals.
•Disconnect the live test lead before disconnecting the neutral test lead.
•Do not use the Meter if the battery indicator (
G
) shows a battery empty
condition.
•Use only Fluke recommended batteries and fuse.
•Do not use the Meter with any parts or cover removed.
•Do not use the Meter around explosive gas, vapor or dust.
•Disconnect the test leads from power sources and from the Meter before
changing the batteries or fuse.
•Do not use the Meter in a wet environment.
•Use only Fluke specified test leads.

Fluke 1520
Users Manual
6
Key functions
Table 1. Key and Switch Descriptions
Rotary switch
To select a measurement function.
T
Used for the Insulation Resistance and Low Resistance test functions.
Press and hold this button until the main reading is stable.
L
Locks the test in Insulation Resistance or Low Resistance function.
To lock: press and hold TEST, then press LOCK and simultaneously release
both buttons. The icon VLOCK appears on the display.
•Insulation Resistance- this mode continuously applies the test voltage
to the circuit to be tested. The beeper sounds every 2 seconds to
remind you that you are in the Lock mode.
•Low Resistance- this mode continuously applies the test current to the
circuit to be tested.
To unlock: press LOCK or TEST again.

MegOhmMeter
Key functions
7
Table 1 (continued)
N
Resistance Beeper function
Turns the Beeper function ON and OFF. When ON, the
R
icon appears on
the display and the Meter beeps at short circuit.
Z
Low Resistance function
Turns the test lead resistance compensation ON.
The
X
icon appears on the display. To compensate, touch the probe tips
together, then press and hold ZERO until the Meter beeps. The main display
indicates 0.00.
C
Backlight button
Turns the display backlight ON and OFF.

Fluke 1520
Users Manual
8
Display
Table 2 and Figure 2 describe the display.
Table 2. Display Description
1 Voltage applied to the probes in Insulation Resistance function.
2 Low Resistance/Resistance function indicator.
3 Resistance reading held from the last measurement in Insulation Resistance or Low
Resistance function.
4 Beeper symbol shows if beeper function is turned on in Resistance function.
5 Zero symbol is on if test leads are zeroed out.
6 Main reading display for all functions.
7 Analog bar graph displays resistance on a logarithmic scale and voltage on a linear
scale. The value always tracks the main reading.
8 High voltage warning symbol flashes if voltage ≥30 V ac or dc is present on the probes.
9Battery life indicator. Displays briefly when the Meter is first switched to a function.
Displays the amount of battery voltage left in increments of 25 %.
10 Lock symbol is on if the TEST mode is locked in Insulation or Low Resistance functions.

MegOhmMeter
Key functions
9
1 32
6
7
9
10
8
45
acf12f.eps
Figure 2. Display

Fluke 1520
Users Manual
10
Using the Meter
Connecting to the Circuit Under Test
Figure 3 shows the proper connections.
W
Warning
To prevent electric shock when performing resistance tests, remove all
power from the circuit to be measured.
W
Warning
To prevent electric shock, first connect the test leads to the Meter inputs
before you make connection to the circuit under test.

MegOhmMeter
Using the Meter
11
acf04f.eps
Figure 3. Connecting to the Circuit Under Test

Fluke 1520
Users Manual
12
Auto-Shut-Off
The Meter automatically turns off after 15 minutes of non-use. In Lo Ohms mode, the meter
turns off after 5 minutes of non-use. To turn the meter back on, turn the rotary switch to
OFF, then to the desired function.
Measuring Insulation Resistance
W
Warning
•Measuring insulation resistance requires the application of potentially
dangerous voltages to the circuit. This may include exposed bonded
metalwork.
•Before proceeding, ensure that the installation is correctly wired and no
personnel are endangered by any tests.

MegOhmMeter
Using the Meter
13
To measure insulation resistance, do the following:
1. Select the test voltage.
2. Connect the probes to the circuit to be measured.
The meter automatically detects if the circuit is energized,
and displays the detected voltage.
W
Warning
A repetitive beep and the flashing high voltage symbol (
Y
)
warn the user if voltage more than 30 V ac or dc is present.
If the voltage is >30 V ac or dc, remove the voltage from the
circuit under test before proceeding with the next step. acf05f.eps
3. Push and hold the TEST button. The upper left display shows the test voltage applied
to the circuit under test. The main display shows the resistance.
Note
The display shows - - - - until the TEST button is pushed.

Fluke 1520
Users Manual
14
The Meter beeps when the reading is stable. The upper right display shows the same
resistance reading as the main display.
When resistance is higher than the maximum display range, the meter reacts as
follows:
•If the 250V range is selected, the display reads >1000 MΩ.
•If the 500V range, is selected, the display reads >2000 MΩ.
•If the 1000V range, is selected, the display reads >4000 MΩ.
4. While keeping the probes on the test points, release the TEST button.
The circuit now discharges through the Meter, while the main reading shows the
decreasing voltage.
Keep the probes touched to the test points until the circuit is completely discharged
(the main display shows - - - -).
The upper right display holds the resistance reading until a new test is started or a
different function is selected.

MegOhmMeter
Using the Meter
15
Using the LOCK Function to Measure Insulation Resistance
The LOCK function holds the test voltage on the probes. Use LOCK to make long duration
measurements without having to push and hold the TEST button.
To use the LOCK function:
1. Press the TEST button, then press the LOCK button, and then release both
simultaneously.
W
Warning
In this mode a potentially dangerous voltage is continuously applied to the
probes.
In this mode, if the probes are disconnected from the circuit, the Meter
cannot discharge any potentially dangerous capacitive voltages left on the
circuit. Caution
In this mode the Meter cannot indicate if the circuit is live.
Ensure that the circuit is de-energized before connecting the test probes in
this mode.
2. Press LOCK or TEST to disengage the lock function.