COMPARISON · MULTIMETERS
Fluke 117 vs Fluke 179
Both are True RMS Fluke meters with a strong reputation among electricians, but they're built for different tiers of work. The 117 is tuned for residential and light commercial wiring, with VoltAlert non-contact voltage detection and a low-impedance AutoVolt input as its standout features. The 179 is the full-featured member of Fluke's 170 series: CAT IV 600V, temperature, frequency to 100 kHz, tighter DC accuracy and a lifetime warranty, aimed at industrial maintenance, HVAC and electronics as much as building wiring.
By the OhmSavvy Research Team ·
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Fluke 117
4.8★★★★★The meter working electricians actually buy with their own money, not just the one brands push.
Fluke 179
4.7★★★★★Fluke's do-everything bench-and-field meter: CAT IV 600V, True RMS, temperature and a 6,000-count display with bar graph.
Specs side by side
| Fluke 117 | Fluke 179 | |
|---|---|---|
| Rating | 4.8★★★★★ | 4.7★★★★★ |
| Accuracy | True RMS | True RMS |
| Safety rating | CAT III 600V | CAT III 1000V / CAT IV 600V |
| Auto-ranging | Yes | Yes (manual override) |
| Best for | Electricians, serious hobbyists | Industrial maintenance, electronics, HVAC |
| Safety rating | CAT III 600V | CAT III 1000V / CAT IV 600V |
| Display | 6,000 counts with 33-segment bar graph | 6,000 counts with analog bar graph |
| Basic DC volts accuracy | ±(0.5% + 2) | ±(0.09% + 2) |
| Basic AC volts accuracy | ±(1.0% + 3) | ±(1.0% + 3) |
| Current | 6A and 10A; 1 mA finest step | Up to 10A; 0.01 mA finest step |
| Resistance | Up to 40 MΩ | Up to 50 MΩ |
| Temperature | No | −40 °C to 400 °C, thermocouple supplied |
| Capacitance | 1 nF to 9,999 µF | Up to 10,000 µF |
| Frequency | 99.99 Hz to 50.00 kHz | Up to 100 kHz |
| Non-contact voltage detection (NCV) | Yes, VoltAlert | No |
| LoZ / AutoVolt input | Yes, about 3 kΩ | No |
| Min/Max-Average recording | Yes | Yes |
| Weight | 550 g | 420 g |
| Battery life (9V) | About 400 h typical | About 200 h typical |
| Warranty | 3 years | Lifetime |
Specs checked against manufacturer documentation and official Amazon listings. Fluke 117 is hands-on tested by OhmSavvy; the Fluke 179 assessment is desk research. How we research.
Key differences
- →The 179 adds a CAT IV 600V rating on top of CAT III 1000V, extending protection closer to a service entrance than the 117's CAT III 600V covers.
- →The 179 measures temperature with its supplied thermocouple; the 117 doesn't measure temperature at all.
- →The 179's basic DC accuracy is ±(0.09% + 2) against the 117's ±(0.5% + 2), and it resolves current to 0.01 mA where the 117 steps in 1 mA.
- →The 179's frequency range reaches 100 kHz, double the 117's 50 kHz; capacitance is effectively the same (10,000 µF on the 179, 9,999 µF on the 117).
- →The 117 has VoltAlert non-contact detection and a low-impedance AutoVolt input for ghost voltage; the 179 has neither.
- →Both have Min/Max-Average recording and a 6,000-count display with a bar graph, and both are True RMS.
Fluke 117 vs 179 spec by spec
On capacitance and AC voltage the two are level: Fluke quotes ±(1.0% + 3) AC volts for both, and both handle motor-run and power-supply capacitors. The 179 pulls ahead on DC accuracy and frequency reach; the 117 answers with twice the quoted battery life.
What does the DC gap look like in volts? On a 24 V control supply, read on the 60.00 V range, the 117's spec allows ±(0.12 + 0.02) = ±0.14 V and the 179's allows ±(0.022 + 0.02) = ±0.042 V. That's arithmetic from Fluke's published figures, not a measurement. For checking that a 24 V supply is alive, either is plenty; for setting a sensor reference or comparing two readings a few tens of millivolts apart, the 179 is the better instrument.
CAT III 600V vs CAT IV 600V: where it matters
A measurement category describes how big a transient the meter is built to survive at a given point in the installation. Closer to the utility transformer, a fault or lightning-induced surge carries far more energy, so the IEC 61010 test levels rise. CAT IV covers the origin of the installation: the service drop, meter base and main disconnect. CAT III covers distribution panels, feeders and fixed equipment.
For a residential electrician, almost all troubleshooting happens in the CAT III and CAT II zones, where the 117 is fully rated. The 179 earns its rating when you test at the meter base, on the line side of a main breaker, or on outdoor service conductors. Our multimeter buying guide explains the categories in more depth.
A rating is not permission
What the 117 does that the 179 can't
The 117's two electrician features are about telling real voltage from false alarms. VoltAlert, a sensor in the top of the meter, beeps and lights near an energized AC conductor with no probe contact, a quick first check before you touch anything. AutoVolt drops the input to about 3 kΩ, which drains the phantom voltage a disconnected wire picks up from live neighbors in the same conduit. A high-impedance meter like the 179 will happily display that phantom as a convincing reading. Our explainer on voltage on a disconnected circuit shows how to unmask it without LoZ.
Fluke 117 vs 179 for HVAC technicians
An HVAC service call asks a meter for four things: capacitance for run and start capacitors, temperature, a clean voltage reading on long control runs, and microamps for the furnace flame sensor. The 117 and 179 split those four between them, and neither covers all of them, which is the most useful thing to know before buying either for HVAC work.
| HVAC check | Fluke 117 | Fluke 179 |
|---|---|---|
| Run or start capacitor | 1 nF to 9,999 µF, ±(1.9% + 2) | To 10,000 µF, ±(1.2% + 2) |
| Supply/return air or line temp | No temperature | −40 °C to 400 °C |
| Ghost voltage on thermostat wire | LoZ AutoVolt, about 3 kΩ | No LoZ |
| Flame-sensor microamps | No: 1 mA steps | No: 0.01 mA steps |
| Cycling load or brownout | Min/Max/Avg | Min/Max-Average |
| Condenser or RTU disconnect | CAT III 600V | CAT III 1000V / CAT IV 600V |
| Live-wire check before work | VoltAlert NCV | Carry a pen tester |
Capacitors first, since they are the most common failure on a no-cool call. Take a 45 µF run capacitor as an illustrative example. The percentage term alone allows about ±0.86 µF on the 117 and ±0.54 µF on the 179, before the two-count term. Run capacitors are commonly printed with a ±5% or ±6% tolerance, roughly ±2.3 to ±2.7 µF on a 45 µF can, so both meters give a clear pass or fail. Capacitance is not a reason to choose one over the other.
Flame sensors are the trap. Flame-rectification current is typically a few microamps, and a useful reading needs a µA range with 0.1 µA resolution. The 117's finest step is 1 mA and the 179's is 0.01 mA, which is 10 µA, so on a sensor running at, say, 3 µA both meters would show zero. If you service furnaces, plan on a meter with a microamp range, such as the Fluke 116 or the Fluke 87V. Our best multimeter for HVAC technicians ranking is built around exactly that requirement.
On safety ratings, both cover the work. Rooftop units, condensers and air handlers are fixed equipment fed from the building's distribution, which is CAT III territory, and both meters are rated there at 600 V or above, enough for 208, 240 and 480 V equipment. The 179's extra CAT IV rating matters to an HVAC tech only if they also probe the service entrance. Where the 117 earns its place is low-voltage controls: a 24 V thermostat cable run beside line-voltage wiring can show a phantom reading on a high-impedance meter like the 179, and the 117's LoZ position collapses it.
Temperature measurement compared
This comparison is one-sided: the Fluke 117 has no temperature function at all. Fluke's 110 Series datasheet gives the thermocouple input to the Fluke 116 only, so if you need temperature in that body, the 116 is the model to buy. The 179 measures temperature with a thermocouple supplied in the box.
| Temperature spec | Fluke 117 | Fluke 179 |
|---|---|---|
| Temperature function | No | Yes |
| Range (meter) | Not applicable | −40 °C to 400 °C (−40 °F to 752 °F) |
| Probe in the box | None | Thermocouple supplied |
| Probe type and rating | Not applicable | Not stated in our sources |
| Temperature accuracy | Not applicable | Not stated in our sources |
For HVAC, −40 °C to 400 °C on the 179 comfortably spans supply and return air, refrigerant line temperatures for superheat and subcooling, and heat-exchanger surfaces. Two caveats. First, the range above is the meter's; a thermocouple probe carries its own rating, and we haven't confirmed the rating of the probe Fluke ships with the 179, so check the probe before measuring anything hot. Second, with one input you take readings in sequence: for a temperature split across a coil (commonly targeted around 15 to 20 °F on cooling), read return air, move the probe, then read supply air. If you need wider range, the Fluke 87V vs 179 comparison covers the 87V's −200 °C to 1090 °C input.
Which one for which electrician
| Work type | Better fit | Why |
|---|---|---|
| Standard residential/light commercial panels | Fluke 117 | VoltAlert and LoZ suit building wiring |
| Service entrances or utility-adjacent work | Fluke 179 | CAT IV 600V rating extends protection further |
| HVAC, motor, or appliance temperature checks | Fluke 179 | Only the 179 measures temperature |
| Motor-run or supply capacitor testing | Either | Both read capacitance up to about 10,000 µF |
| Sensor loops and small DC currents | Fluke 179 | 0.01 mA resolution and ±(0.09% + 2) DC |
| Remodels with shared conduits and dead legs | Fluke 117 | LoZ collapses ghost voltage |
A residential electrician usually doesn't need the 179's extras
Choose the Fluke 117 if…
- ✓You're a residential or light commercial electrician working standard panels and branch circuits
- ✓Non-contact voltage detection and a LoZ ghost-voltage check are features you'll use daily
- ✓You don't need temperature measurement or frequency readings above 50 kHz
- ✓You want longer battery life: Fluke quotes 400 hours against the 179's 200
Choose the Fluke 179 if…
- ✓You need the CAT IV 600V rating for service-entrance or utility-adjacent work
- ✓You regularly measure temperature as part of your troubleshooting
- ✓You read small DC currents or need tighter DC voltage accuracy
- ✓You want CAT III 1000V headroom and a lifetime warranty
The bottom line
For most residential and light commercial electricians, the 117 is the more practical choice: its CAT III 600V rating covers standard panel work, VoltAlert and LoZ solve everyday false readings, and it runs twice as long on a battery. The 179 earns its higher price for work that needs CAT IV protection, temperature, tighter DC accuracy or a lifetime warranty: industrial maintenance, HVAC and electronics more than routine residential troubleshooting.
Frequently asked questions
Is the Fluke 179 simply a better version of the 117?+
Not exactly. It trades VoltAlert and LoZ for a higher CAT rating, temperature, tighter DC accuracy and a wider frequency range. Both are True RMS with the same AC volts accuracy, and each has features the other lacks, so the choice depends on the work you do rather than which meter is newer or dearer.
Do residential electricians actually need CAT IV 600V?+
Usually not. CAT III 600V, the 117's rating, covers distribution panels, branch circuits and fixed equipment, which is most residential and light commercial work. CAT IV matters at the origin of the installation: the meter base, service drop and line side of the main disconnect.
Why doesn't the 179 have non-contact voltage detection?+
Fluke doesn't give a reason. It lists VoltAlert as a 117 feature and leaves it off the 170 series, which it positions as general troubleshooting meters. If you choose the 179, carry a separate non-contact voltage tester for quick checks, and use the meter's probes to confirm before touching anything.
Can the 179 do everything the 117 can, plus more?+
Almost, but not entirely. It lacks VoltAlert non-contact detection and the low-impedance AutoVolt input, so it can't drain a ghost voltage the way the 117 does. Beyond those, the 179 extends further in DC accuracy, current resolution, frequency and temperature, and adds CAT IV 600V.
Which Fluke has the better warranty, the 117 or the 179?+
The 179. Fluke lists a lifetime warranty for it against three years for the 117. Over a long career that's a real difference, though both are built for daily field use. Choosing the 117 for VoltAlert and LoZ means accepting the shorter term; choosing the 179 for CAT IV and temperature brings the longer one with it.
Is the Fluke 117 or 179 better for HVAC work?+
For most HVAC techs, the 179, because it measures temperature and reads capacitance slightly more accurately, ±(1.2% + 2) against ±(1.9% + 2). The 117 wins only on control wiring, where its LoZ position clears ghost voltage on long thermostat runs. Neither has a microamp range, so furnace flame-sensor checks need a third meter such as the Fluke 116 or 87V.
Can the Fluke 179 test a furnace flame sensor?+
Not usefully. Its finest current step is 0.01 mA, which is 10 µA, and Fluke lists no microamp range. Flame-sensor current is typically a few microamps, so the 179 would read zero or a single count. Use a meter with a µA range and 0.1 µA resolution, such as the Fluke 116 or Fluke 87V, in series with the flame rod lead.
Does the Fluke 117 measure temperature?+
No. Fluke's 110 Series datasheet gives the thermocouple input to the Fluke 116, not the 117. The 179 reads −40 °C to 400 °C with a thermocouple in the box. If you want a 110 Series body with LoZ plus temperature and microamps, the 116 is the HVAC model in that family.
What temperature probe comes with the Fluke 179?+
Fluke says the 179 ships with a thermocouple, and the meter reads −40 °C to 400 °C. We haven't confirmed the supplied probe's type or its own temperature rating from Fluke's specifications, so treat that as not stated. A probe can be rated lower than the meter, so check the marking on the probe before measuring hot surfaces or flue gas.
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