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Test & Measurement FAQs

Clamp Meter

  1. Can the non-contact voltage sensor differentiate between hot and neutral?
  2. The non-contact voltage (NCV) sensor is very sensitive. So, there are two methods to determining the hot and neutral slots on an outlet.

    Method One: To differentiate between hot and neutral in an outlet, insert the NCV sensor into each slot of the outlet. The beeper is much louder in the hot side of the outlet than the neutral.

    Method Two: the test leads can also be used to differentiate between hot and neutral. Insert the red test lead into the + port and slide it into the test probe holder on the side of the clamp. Press the NCV button and insert the test probe into each side of the outlet. The beeper will only beep on the hot side of the outlet.

  3. What is the vibration mode on the 61-702?
  4. The vibration mode on the 61-702 emulates a Vol-Von solenoid tester vibrating when AC voltage is being tested. The level of vibration noticeably increases at 120,240,480,and 600VAC intervals.
  5. What is the Harmonics Indicator on the 61-702 ?
  6. During AC Voltage measurements, the 61-702 indicates the presence of harmonic distortion. If the line voltage has less than 5% (+2%) total harmonic distortion (THD), the green LED lights up, indicating that the circuit has clean power. If the line has more than this THD level, a True RMS meter should be used to obtain accurate voltage measurements. To accurately measure the harmonics, the SureTest Circuit Analyzer (61-156) can be used.
  7. What is the advantage of silicone test leads?
  8. Silicone test leads are a more expensive, higher quality lead than the standard lead. These leads have less resistance, have a good feel, stay flexible in very cold weather and can withstand high temperatures without melting.
  9. How does the non-contact voltage (NCV) work on the 61-701 and 61-702 ?
  10. With the switch in the "Off" position, depress the NCV button (an audible chirp should be heard). Place the sensor on the tip of the clap close to a known AC voltage to ensure proper operation (audible beep). Now, place the sensor to the outlet or wire under test. An audible beep and LED indication will appear of the voltage is between 40-600VAC. The closer the NCV sensor is to AC voltage, the louder the unit beeps.


  1. Can you calibrate meters?
  2. All of IDEAL meters are factory calibrated. Certification may be obtained at an additional charge.
  3. I am not registering an AC Amp reading with my current clamp?
  4. 1. For a current clamp to work properly you must clamp around only the hot or the neutral conductor.
    2. Ensure the circuit is under a load. (Ex. hair dryer, toaster, heat gun, ect.)
  5. How do I buy a multimeter?
  6. IDEAL products may be purchased through your local electrical distributor. Go the the quick menu and click on Distributor Locator or contact our Customer Service Department at 800-435-0705 between 7AM and 7PM Central time.
  7. What do the category ratings on a digital multimeter mean?
  8. The purpose of the category rating is to rate the meter on the amount of overvoltage protection that a meter has. For example, if a user is measuring line voltage while at the same time a lightning strike occurs or a large motor on the same circuit is turned on/off, the meter can be exposed to a transient voltage of 6000 V (or 6kV) for just a fraction of a second. The meter should be able to withstand this overvoltage and protect the user from any harm.

    The category ratings on digital multimeters reflect the voltage level that they were tested for within the various installation categories as set up by IEC and adopted by the new UL standard (UL3111-1). For example, a Cat III - 600V rating specifies that the multimeter met the safety requirements prescribed by UL for testing up to 600V in an installation category III environment. The installation category levels are as follows:

    Category I: Board level troubleshooting
    Category II: Portable equipment troubleshooting
    Category III: Troubleshooting equipment connected directly - to the distribution system or the distribution - system itself.
    Category IV: Measurements at the source of the power
    source (direct connection to the utility)

    Energy surges through an electrical system, like a transmission line struck by lightning, dissipate through the system. the category voltage ratings reflect the level of protection provided by the instrument.


  1. What is the lead input warning feature ?
  2. The most common cause of fuses blowing within digital multimeters is when voltage measurements are taken while the test leads are plugged into the current ports. All the PlatinumPro models are fuse protected to protect the meter, but the 630 series has a lead input warning feature to help prevent this mistake. When the function switch is turned to a current measurement (DC, AC or AC+DC), the meter give an audible and visual alarm if the probes are not in the correct port. "Probe" is displayed in the LCD and the meter beeps until the switch or probes are changed.
  3. What is the peak min/max feature on the 61-482 ?
  4. The peak min/max feature works very much like a peak hold, except it captures the highest and lowest peak values seen by the meter.
  5. What is True RMS?
  6. True RMS is a method for calculating the value of AC current and voltage measurements, using the Root Mean Squared (RMS) value of the wave form. True RMS multimeters are accurate when harmonic distortion is present or if the waveform is not a true sine wave. Average responding meters could be off as much as 10-40% under these conditions.
  7. What is the high/low limit feature on the 630 series?
  8. High and low limits may be set on the digital multimeter for data comparison. An audible alarm sounds if the measurement value has fallen outside these established limits. The triple display of the 630 allows a visual display of the measurement value and the high/low limits.
  9. What is the difference between max hold and peak hold?
  10. Max hold is designed to store the highest reading seen during normal measurement. This is different than the peak hold feature, which is designed to store the highest peak measurement. The peak value is the maximum amplitude of the wave form. The peak is important for monitoring in-rush current caused by motors starting up. For example, when measuring 120VAC line voltage, the max voltage may be 124VAC, while the peak voltage may be 172VAC for just a few milliseconds.
  11. What is relative mode and how is it used?
  12. In relative mode, the digital multimeter stores a measurement value to use as a baseline measurement. future measurements are compared to this baseline measurement and displayed as the difference from it. This feature is also used to "zero out the leads" when taking very low reisitance measurements in order to compensate for the resistance of the leads.
  13. Why is it important to have an optically isolated RS232 connection?
  14. The optical isolation protects the computer from any power surges that the digital multimeter may experience while being connected to the line and recording in the data acquisition mode.
  15. What is the difference between data acquisition and data logging?
  16. Data acquisition allows the digital multimeter to interface directly to a computer. Multimeters with data acquisition require the meter to be connected to the computer when recording data. Sometimes this is inconvenient when recording data. First, the user has to haul a laptop around to each recording place. Second, if the measuring need is in a dirty, industrial location, user maybe concerned about his/her computer being exposed to dirt and grime. Third, if the user is acquiring data over a longer period of time, he/she may be concerned about computer theft since it will be left unattended for hours or days.

    Multimeter with a data logging feature allow the meters to capture and store data in their built-in memory banks. So, a computer is not needed to record data. At a later point in time, the meter can then be connected to a computer to download the data and analyze it on the computer screen.

Power Analyzer

  1. Can the 800 Series power clamps measure all these types of power?
  2. In addition to AC and DC current, resistance and temperature, the 61-800 power clamp will measure true power, while the 61-802 measures all four of these power measurements. It has a dual display so true power and power factor, or apparent power and reactive power can be viewed simultaneously.
  3. What is power factor ?
  4. Power factor is a measure of the efficieny of an electrical system. A company with poor power factor is using their power inefficiently and therefore wasting power. Power factor is the ration of true power (watts or kilowatts) to apparent power (volt amps), or in other words the amount of power used to the system capacity. This gives you a measurement of how well a system can use the energy provided by the utility.
  5. What is power quality?
  6. Power quality is a broad term that is used to describe the performance of an electrical power system. Power quality problems range from minor annoyances, like lights dimming or flickering, to major problems like machines shutting down during production or computers crashing during data transfer.
  7. Why is power quality important?
  8. Poor power quality can cause a number of problems, including: lost productivity, lost or corrupt data, damaged equipment and poor power efficiency. According to a study done by Electrical Contractor Magazine, US companies waste about $26 billion each year.
  9. Why wouldn't the true power (watts) and apparent power (volt amps) be the same?
  10. In a perfect system they actually are the same. This would result in power factor of 1.0. There is another component called reactive power. Reactive power is power used within a facility to energize magnetic fields, such as a capacitor. This energy is necessary to run the facility, but not actually useable power.
  11. What are harmonics?
  12. In simple terms, harmonics are distortion, created by electronic equipment on an electrical power system. This equipment creates distortion at frequencies, which are multiples of the fundamental frequency.
  13. How do I measure the %THD?
  14. There are a variety of products on the market that will measure the %THD, but none are as simple to use as the SureTest® Circuit/Harmonics Analyzer. It measures the distortion on the line voltage and neutral current by simply plugging it into a receptacle. It will also break the distortion down so you can measure how much distortion occurs at each individual odd harmonic.
  15. Can the 800 Series power clamps measure all these types of power?
  16. In addition to AC and DC current, resistance, and temperature, the 61-800 power clamp will measure true power, while the 61-802 measures all four of these power measurements. It has a dual display so true power and power factor, or apparent power and reactive power can be viewed simultaneously.
  17. How do I calculate these measurements in a three-phase system?
  18. The 61-802 has been designed to do these calculations for you. Simply attach the voltage leads to a single phase, clamp around the phase conductor and store the readings into the memory of the clamp meter. After this process has been repeated for each phase, the clamp meter will calculate the total system power measurements.


  1. Can the SureTest be used to test ground impedance on GFCI receptacles?
  2. No, the SureTest measures the ground impedance by pulsing a load through the ground conductor. This will trip a GFCI receptacle.
  3. What can high voltage drop readings indicate?
  4. Excess voltage drop can indicate:
    • High resistance connections at wiring junctions or outlet terminals caused by
    • Poor splices
    • Loose or intermittent connections
    • Corroded connections
    • Inadequate wire seating in back-wired connections on "push-in type" receptacles and switches
    • Faulty switches and receptacles
    • Undersized wire for the load or length of run
  5. How much voltage drop measurement is unacceptable?
  6. It is difficult to say at what point excess voltage drop is hazardous, because it depends on how much current is flowing through the high resistance connection. A footnote in the National Electric Code states that the maximum total voltage drop for a combination of the branch circuit and feeder shouldn't exceed 5%. [210-19(a) FPN No. 4]
  7. What are the consequences of these conditions?
  8. Excess voltage drop can cause:
    • Low voltage to equipment on the circuit causing
    • Inefficient or erratic operation
    • Damage to the equipment
    • Poor power efficiency and wasted energy
    • Heating at high resistance connections may result in a fire at high ampere loads
  9. What does a reading of High on the ST-1D display mean when measuring ground to neutral voltage?
  10. This indicates that the ground to neutral voltage is greater than 2 volts. High ground to neutral voltage indicates that the circuit may be loaded near its capacity or the neutral conductor may be shared, or carrying harmonic distortion.
  11. What does it mean when the LED is flashing when measuring ground to neutral voltage?
  12. The flashing display indicates that the SureTest is unable to take the measurement because of a wiring error. If the receptacle had no ground, it would not be possible to measure the ground to neutral voltage. Check the wiring indicator of the SureTest prior to moving through the programming menu.
  13. How does the SureTest test GFCI receptacles?
  14. All SureTest analyzers send bleed 6mA through a fixed resistor from the hot conductor to the ground conductor. This conforms to UL 1436 specification for receptacle testers.
  15. How do I know if my GFCI tripped quickly enough?
  16. SureTest models ST-P+, ST-1D and ST-1THD will calculate the time it took for the GFCI receptacle to trip. As the current is being bled from hot to ground, the SureTest will count up until the power is cut off by the GFCI. When power is restored, the unit will display the actual trip time in tenths of a second. This can then be compared to the specification of the GFCI receptacle to ensure that it within tolerance.
  17. What are harmonics?
  18. In simple terms, harmonics are distortion, created by electronic equipment on an electrical power system. This equipment creates distortion at frequencies, which are multiples of the fundamental frequency.