Fluke 17B+ vs Fluke 117

Specs side by side

Specs checked against manufacturer documentation and official Amazon listings. Fluke 117 is hands-on tested by OhmSavvy; the Fluke 17B+ assessment is desk research. How we research.

Key differences

• →The 117 is True RMS; Fluke makes no True RMS claim for the 17B+.
• →Only the 117 has VoltAlert non-contact detection, AutoVolt and a low-impedance mode.
• →The 17B+ adds temperature with an included Type K probe, duty cycle, relative mode and µA and mA current ranges.
• →The 17B+ reads up to 1000V and 100 kHz; the 117 stops at 600V and 50 kHz.
• →The 117's 6,000-count display and bar graph are finer than the 17B+'s 4,000 counts.
• →Fluke's manual gives the 17B+ a 1-year warranty against 3 years for the 117.
• →The 17B+ Amazon listing's photo shows the newer 17B MAX, so check which model ships.

Fluke 17B+ vs 117 spec by spec

The 17B+ reaches further on frequency and voltage, while the 117 shows readings with finer resolution. Which matters depends on whether you chase signals or confirm mains. Basic DC accuracy is nearly identical: ±0.5% of reading on both, with one extra count on the 17B+. On the 400 V range that count is 0.1 V; on the 117's 600 V range a count is also 0.1 V, so in practice you will not see a difference on a battery or a receptacle.

The 6,000-count display matters more on the 117 than the number suggests. A 4,000-count meter switches from its 40 V range to its 400 V range at 40 V, so a 48 V telecom or solar battery reads to 0.1 V on the 17B+, while the 117 keeps it on its 60 V range with 0.01 V steps. The 17B+'s 4,000 counts are fine for 12 V and 24 V systems, which stay on the 40 V range.

Fluke 17B+ vs 117 for electrical work

For electrical work the Fluke 117 is the better meter, and accuracy has little to do with it. An electrician opening receptacles, switch boxes and panels repeats three questions all day: is this conductor energized, is the number on the screen real, and is it AC or DC? The 117 has a dedicated feature for each. The 17B+ answers them with the test leads and the user's judgment, which works, but more slowly and with more room for a wrong call.

Ghost voltage is where the gap shows most. A disconnected conductor pulled alongside live ones picks up voltage by capacitive coupling, and a meter with an input above 10 MΩ, like the 17B+, barely loads it, so a dead wire can read a convincing few dozen volts. The 117's AutoVolt position puts roughly 3 kΩ across the leads, more than 3,000 times less, and that induced reading sags toward zero while a genuinely energized conductor holds its value. The 17B+ has no LoZ mode for making that distinction; its hazard LED is specified only as lighting at 30 V or more.

At an outlet, the sensible routine on the 117 is VoltAlert first to find the hot box, then the leads on AutoVolt, then live-dead-live on a known source before declaring a circuit off. On the 17B+ the same job skips the first step and needs a dial change between AC and DC. In the panel, the two carry the identical CAT III 600V rating; the 17B+'s extra CAT II 1000V line covers plug-in equipment, not the bus or the breakers, and neither meter is rated CAT IV for the service entrance.

Current is close to a tie. Both read up to 10 A with the leads in series, both state AC current at ±(1.5% + 3), and Fluke lets the 117 carry 20 A for 30 seconds; the 17B+'s overload allowance beyond its 11 A fuse is not stated. A loaded 15 A or 20 A branch circuit is a job for a clamp, not the A jack of either meter (see how to measure AC current with a clamp meter). The one electrical task where the 17B+ wins is a furnace flame-sensor or control-loop reading in microamps or milliamps, covered below. For everyday wiring, the 117 and its peers in our best multimeter for electricians guide are the meters to carry.

Fluke 17B+ vs 117: accuracy compared

Fluke writes every accuracy figure as ±(percent of reading + counts). The percentage scales with the number on the display; the counts are a fixed number of steps in the last digit of whatever range the meter is on. That second term is why the same spec can be tight on one reading and loose on another, and why display counts and accuracy have to be read together. Here is every published line the two meters share, from Fluke's spec pages and manuals as cited above; where Fluke publishes no figure, we say so.

Worked example one, a car battery at 12.6 V DC. Both meters sit on a range with 0.01 V steps (the 17B+'s 40.00 V range, the 117's 60.00 V range). The percentage term is identical: 0.5% of 12.6 V is 0.063 V. The 117 adds 2 counts (0.02 V) for a band of ±0.083 V, so the true voltage lies between about 12.52 V and 12.68 V. The 17B+ adds 3 counts (0.03 V) for ±0.093 V, or about 12.51 V to 12.69 V. A hundredth of a volt apart: irrelevant for telling a charged battery from a flat one.

Worked example two, a 120 V receptacle. The 17B+ reads it on its 400.0 V range and the 117 on its 600.0 V range, both in 0.1 V steps, and both specify AC volts at ±(1.0% + 3). That gives 1.2 V plus 0.3 V, so ±1.5 V and a band of 118.5 V to 121.5 V on either meter. The catch is the waveform: that figure holds for a clean sine on both, but only the 117 is True RMS, so on a dimmer, drive or LED-driver circuit Fluke gives the 17B+ no accuracy figure at all.

Worked example three shows where the count term bites. A 48 V battery bank pushes the 17B+ onto its 400.0 V range, where 3 counts are 0.3 V: 0.5% of 48 V (0.24 V) plus 0.3 V is ±0.54 V. The 117 stays on its 60.00 V range, where 2 counts are 0.02 V, so ±0.26 V, about half the band. On a 48 V solar or telecom system that gap is the difference between seeing a 0.3 V string imbalance and losing it in the error band.

Outside volts, the picture splits. The 17B+'s best resistance line, ±(0.5% + 2), is tighter than the 117's ±(0.9% + 1), though its higher ranges loosen to ±(1.5% + 3); the 117 is tighter on capacitance and by one count on frequency. Neither difference decides a purchase. If accuracy on a bench is the real question, our guide to multimeter accuracy for electronics repair explains when a tighter spec actually changes a diagnosis.

Small currents: where the 17B+ pulls ahead

The biggest functional gap isn't temperature, it's current. The 17B+ has six current ranges from 400.0 µA to 10 A, all at ±(1.5% + 3), through a separate µA/mA jack protected by a 440 mA, 1000 V fuse. The 117 has only its 6 A and 10 A ranges. Its best resolution is 1 mA, so a 4-20 mA control loop reads as a handful of whole milliamps, and a furnace flame-sensor signal of a few microamps doesn't register.

On the 17B+, a 12.00 mA loop reading sits on the 40.00 mA range at 0.01 mA resolution. That is the kind of job the 117 was never designed for. For the method, see how to measure microamps with a multimeter or our best multimeters for 4-20 mA loop testing.

Function checklist

Temperature on the 17B+: how accurate is it?

Fluke specifies the 17B+'s thermocouple input in three bands. From 50 °C to 400 °C it is ±(2% + 1 °C), so a 200 °C heatsink or oven reading carries about ±5 °C (2% of 200 is 4 °C, plus 1 °C). From 0 °C to 50 °C it is ±2 °C, good enough for supply and return air. Below freezing the spec loosens to ±(9% + 2 °C), so a -20 °C freezer reads within about ±3.8 °C. Those figures cover the meter only; any thermocouple probe adds its own tolerance on top.

The 117 has no temperature function at all. Fluke's datasheet puts the thermocouple input on the Fluke 116, the HVAC model of the 110 Series. For thermocouple checks themselves, see how to check a thermocouple with a multimeter.

Fluke 17B+ vs Fluke 117: which should you buy?

We have owner-tested the 117; the 17B+ assessment is desk research against Fluke's specifications. For the 17B+ against its simpler twin, read Fluke 17B+ vs Fluke 15B+; for the full Fluke write-up, see our Fluke 117 review.

Frequently asked questions