Fluke 115 vs 117: Do You Need LoZ, AutoVolt and VoltAlert?

Choose the Fluke 117 for electrical troubleshooting when LoZ, automatic AC/DC voltage selection and built-in VoltAlert are useful; choose the Fluke 115 for routine field service when you do not need those extras. Both have True RMS, a 6,000-count display and matching specified accuracy on their conventional voltage and current ranges. If you need temperature measurement or dedicated mA/µA ranges, choose neither.

Quick picks

Compare specifications and all conditions

Electrical troubleshooting with ghost-voltage checks

Our pick

Fluke 117

Why

AutoVolt/LoZ and integrated non-contact AC detection

Field service using conventional measurement functions

Our pick

Fluke 115

Why

Matching conventional voltage/current specifications without those extras

Temperature or very small-current work

Our pick

Neither

Why

No temperature function or dedicated mA/µA range

Full comparison table ↔

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Your buying decision	Our pick	Why
Electrical troubleshooting with ghost-voltage checks	Fluke 117	AutoVolt/LoZ and integrated non-contact AC detection
Field service using conventional measurement functions	Fluke 115	Matching conventional voltage/current specifications without those extras
Temperature or very small-current work	Neither	No temperature function or dedicated mA/µA range

Your buying decision	Our pick	Why
Electrical troubleshooting with ghost-voltage checks	Fluke 117	AutoVolt/LoZ and integrated non-contact AC detection
Field service using conventional measurement functions	Fluke 115	Matching conventional voltage/current specifications without those extras
Temperature or very small-current work	Neither	No temperature function or dedicated mA/µA range

Both are specified for 600 V, with 6,000 display counts and CAT III 600V protection. These are manufacturer specifications, not independently verified performance.

• 600 VMaximum voltage between any terminal and earth ground, both models
• 6,000 countsDigital display, both models
• CAT III 600VSafety rating as specified by Fluke, both models

Best for electrical troubleshooting: Fluke 117

The 117 is our pick when its additional voltage functions belong on your work checklist. Fluke's model page identifies AutoVolt, VoltAlert and low-impedance voltage measurement as the differences from the 115. Those are useful reasons to select it; matching conventional-range specifications give no reason to expect more accurate ordinary DC readings.

The limitation is shared with the 115: this is an amp-range meter without dedicated small-current ranges or temperature measurement. If those are essential, choose the appropriate functions before choosing between these models.

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Best for routine field service: Fluke 115

The 115 fits a checklist built around voltage, amp-range current, resistance, continuity, diode testing, capacitance and frequency. It also has a backlight, Hold and Min/Max/Average recording. You keep autoranging: missing AutoVolt does not mean manually selecting every numerical range.

Choose it when the 117's additional functions would go unused. For sensitive electronics, remember that the 117 also retains conventional high-impedance voltage functions; the 115 is not uniquely suitable merely because it lacks AutoVolt/LoZ.

Check the Fluke 115 standard US package at Fluke.

Fluke 115 vs 117: the function table

Accuracy below means ±(% of reading + counts). The shared users manual identifies which models each function applies to.

Frequency limit conflict: the US product-page tables and extended specification sheet specify voltage-input frequency to 50 kHz. The 115 page also retains an inconsistent 30 kHz footnote. The shared manual instead specifies 99.99 kHz, with extra input-sensitivity qualifications above 50 kHz; all agree on 45 Hz–5 kHz for current-input frequency. If your purchase depends on voltage-frequency measurement above 30 kHz, get clarification from Fluke rather than treating the higher figures as settled.

What LoZ, AutoVolt and VoltAlert actually add

AutoVolt and autoranging solve different problems. Autoranging selects a range within a function on both meters. The 117's AutoVolt selects AC or DC voltage and simultaneously uses an input impedance of approximately 3 kΩ, according to the manual. It is the same dial function that provides LoZ voltage measurement.

LoZ helps with ghost voltage, but loads the circuit. Fluke's stray-voltage application note explains how capacitive coupling can create confusing readings on adjacent unconnected wiring. A low-impedance input loads that weakly coupled source. Fluke also warns that low-impedance instruments can affect sensitive control and electronic circuits. The conventional DC voltage input on both meters is specified above 10 MΩ; select a function appropriate to the circuit and the manual.

The 115's Lo-Z capacitance option is different. The shared manual explicitly includes a low-impedance capacitance power-up option for both models. That does not give the 115 the 117's AutoVolt/LoZ voltage function. A bare claim that the 115 has “no LoZ” misses this distinction.

VoltAlert detects AC presence without contact. It adds audible and visual indication on the 117. Fluke warns that voltage can still be present without an indication and that shielded wire can defeat detection. Treat it as a presence indicator, not proof that equipment is safe to touch; our non-contact voltage tester guide covers the buying decision separately.

• Yes: Choose the 117 when you need built-in LoZ voltage measurement.
• Yes: Choose the 117 when automatic AC/DC selection is useful.
• Yes: Choose the 117 when integrated non-contact AC detection belongs in your kit.
• Partly: Choose the 115 when the shared conventional functions cover your work.

Accuracy and current: compare the same range

On the 600.0 V DC range, both meters resolve 0.1 V and specify ±(0.5% + 2 counts). For a hypothetical 100 V reading, the calculation is ±[(0.5% × 100 V) + (2 × 0.1 V)] = ±0.7 V for either meter. This is a calculated specification allowance, not a measurement we made. The 117's additional voltage modes do not improve this result.

The 117's AutoVolt/LoZ mode has its own 600.0 V range, 0.1 V resolution and ±(2.0% + 3) DC accuracy. Compare the ordinary DC functions when judging precision; AutoVolt/LoZ serves a different purpose. Fluke specifies accuracy for one year after calibration, at 18–28 °C and 0–90% relative humidity.

Display count also differs from accuracy. Both digital displays update four times per second, and both have a 33-segment bar graph updating 32 times per second, per Fluke's specifications. Neither provides a display-count advantage here.

For current, the 6 A range resolves 0.001 A, equivalent to 1 mA; the 10 A range resolves 0.01 A. Neither offers a dedicated milliamp or microamp range. Do not mistake that first resolution figure for suitability for every small-current task.

Nor is either a continuous 20 A meter. The manual marks accuracy above 10 A unspecified and limits above 10 A through 20 A to 30 seconds on, 10 minutes off. For other current-measurement needs, use our clamp meter vs multimeter comparison to choose the instrument type.

How we choose

This comparison is document research, with no physical testing. We compared Fluke's US product pages, the shared users manual, the extended specifications and the maker's explanation of stray voltage. Recommendations reflect function fit, matching-range accuracy and package contents. Where Fluke's own documents disagree, we identify the conflict rather than silently choosing a figure. See How we choose and How we measure.

Buying guide: check the exact US package

Included leads, holster and paperwork

For the standard US Fluke 115, part 2538790, Fluke lists the meter, holster, installed 9 V battery and 4 mm PVC-insulated test leads. Its box-content section names a Quick Reference Guide; its model inventory names a user manual. Confirm the supplied paperwork rather than assuming both documents are included.

For the standard US Fluke 117, part 2538815, the model inventory lists 4 mm silicone test leads, holster and user manual. Both models specify a 9 V alkaline battery, approximately 400 hours without the backlight, and a three-year warranty.

Lead descriptions conflict across regions: Fluke's UK 115 page lists silicone leads in one section and PVC-insulated leads elsewhere. Use the US part number and its stated contents for a US purchase; ask for confirmation if a listing promises a different lead set. A compatible-accessories list does not establish what comes in the box.

CAL and factory-reconditioned versions

Choose CAL for the supplied documentation your workplace requires. Fluke describes the reconditioned versions as restored to original factory specifications, but does not enumerate their accessories in those model entries; confirm the inventory. Neither label turns a 115 into a 117.

Before Black Friday or Cyber Monday, compare the exact packages using this order. Keep this comparison focused on the model decision; our broader Fluke vs Klein guide covers cross-brand alternatives.

1. 1

   Match the model

   Confirm the meter has the functions your work requires.

2. 2

   Match the documentation

   Decide whether supplied calibration data is required.

3. 3

   Match the accessories

   Compare the stated lead set, holster and paperwork.

4. 4

   Match the condition

   Compare new packages with new packages, or deliberately choose factory reconditioned.

Verdict

Buy the Fluke 117 when you need its LoZ voltage input, AutoVolt or integrated VoltAlert. Buy the Fluke 115 when their shared conventional measurement functions meet your needs. Choose outside this pair for temperature or dedicated small-current ranges, and compare the exact package before treating an offer as equivalent.