Fluke 117 Multimeter Review: Professional Electrical Diagnostics for Confident Caravanners
- Caravan Coach
- Dec 6, 2025
- 7 min read
Product Category: Digital Multimeter / Electrical Test Equipment
Brand: Fluke
Prices Usually Range From: £235 - £340
Best For: Caravanners who want professional-grade electrical fault diagnosis with non-contact voltage detection
Where to Buy: Available at RS Components, Test-Meter.co.uk, or major retailers like Amazon
Fluke 117 Multimeter - Introduction
When you arrive at a pitch and plug into the hook-up only to find no power reaching your caravan, the question immediately arises: is the problem with the site bollard, your hook-up cable, or something within the caravan itself? A quality multimeter transforms this frustrating guessing game into a methodical diagnosis that takes minutes rather than hours.
The Fluke 117 multimeter has earned its reputation as the electrician's multimeter of choice, and it translates remarkably well to caravan applications. Its integrated VoltAlert non-contact voltage detection allows you to quickly identify where power stops flowing without needing to expose live connections or risk accidental contact. Simply wave the top of the meter near a cable or connection point, and it will alert you to the presence of AC voltage.
For caravanners, this means systematically checking the bollard outlet, then running the meter along your hook-up cable, and finally testing at the caravan inlet to pinpoint exactly where a fault has occurred. Combined with True RMS accuracy for reliable readings and a CAT III 600V safety rating suitable for pitch supplies, the Fluke 117 provides the diagnostic capability that turns electrical problems from stressful mysteries into solvable puzzles.
Key Features
The Fluke 117 combines professional-grade measurement capabilities with features specifically useful for diagnosing caravan electrical systems. The VoltAlert technology provides integrated non-contact voltage detection through a sensor at the top of the meter, allowing you to confirm the presence of AC voltage without making physical contact with conductors. This proves invaluable when tracing power through hook-up cables or checking whether voltage is reaching specific points in your caravan's distribution system.
True RMS measurement ensures accurate readings even when testing non-linear loads or circuits affected by electronic equipment, which is increasingly relevant as caravans incorporate more sophisticated charging systems and inverters. The AutoVolt function automatically distinguishes between AC and DC voltage, saving time when switching between testing mains hook-up circuits and 12V leisure battery systems.
A particularly useful feature for caravan diagnostics is the LoZ (Low Input Impedance) mode, which helps eliminate false readings caused by ghost voltages. In caravan wiring, where circuits often run close together within confined spaces, capacitive coupling can create phantom voltage readings that confuse diagnosis. The LoZ function filters these out to show genuine live circuits.
The large 6000-count display with white LED backlight ensures readings remain visible when working in storage lockers, under beds, or in other poorly lit areas typical of caravan electrical access points. The compact dimensions of 167 x 84 x 46mm and 550g weight make it practical to keep in your caravan toolkit without consuming excessive space.
Pros and Cons
Pros
• VoltAlert non-contact voltage detection makes tracing power faults quick and safe
• True RMS accuracy provides reliable readings on all circuit types
• AutoVolt automatically selects AC or DC measurement mode
• LoZ mode eliminates misleading ghost voltage readings
• Rugged construction withstands the demands of travel and outdoor use
• Bright LED backlight for working in dark caravan compartments
• Compact size fits easily in caravan tool storage
• 400-hour battery life minimises maintenance
• Three-year manufacturer warranty reflects build confidence
Cons
• Premium price point compared to basic multimeters
• No milliamp or microamp measurement for detailed electronics work
• CAT III rating limits heavy industrial use (though suitable for all caravan applications)
• Counterfeit units reported from unauthorised sellers
Performance
The Fluke 117's True RMS capability becomes relevant the moment you're testing anything beyond a simple resistive load. Budget meters use averaging circuits calibrated for pure sine waves, which works fine for measuring a battery but produces errors of 10% or more when measuring the output of an inverter or the charging current from a modern switch-mode power supply. True RMS calculates the actual heating value of the waveform regardless of its shape, giving accurate readings whether you're checking mains hook-up voltage or the modified sine wave output from a leisure battery inverter.
The 6000-count display resolution translates to practical accuracy. When measuring 12V DC, the meter displays to 0.001V increments, allowing you to distinguish between 12.73V and 12.68V on your leisure battery. This precision matters when assessing state of charge, where the difference between 12.7V (100%) and 12.4V (75%) represents significant remaining capacity. A 2000-count meter would show both as 12.7V or 12.6V, hiding useful information.
Input impedance explains why cheap meters show phantom voltages that don't exist. Standard multimeters present 10 megohms input impedance, which is high enough that capacitive coupling between adjacent wires can create misleading voltage readings. The Fluke 117's LoZ mode drops input impedance to around 3 kilohms, effectively loading the circuit enough to collapse any voltage that isn't backed by a genuine source. In a caravan where 230V mains wiring runs alongside 12V circuits within the same trunking, this eliminates confusion when tracing faults.
VoltAlert detection operates through capacitive coupling with AC electric fields, sensing voltage presence through cable insulation without requiring galvanic contact. The sensor at the meter's tip detects fields from approximately 90V AC upward, providing both visual and audible alerts. Sensitivity is sufficient to detect live conductors through standard cable sheathing, though thick insulation or shielded cable reduces range. For tracing power through a hook-up cable or confirming voltage at a caravan inlet, detection is reliable at several centimetres distance.
DC voltage accuracy of ±0.5% plus 2 digits means a reading of 12.50V on your leisure battery is actually somewhere between 12.42V and 12.58V in the worst case. In practice, the meter typically performs better than specification. AC voltage accuracy of ±1.0% plus 3 digits reflects the additional complexity of RMS calculation. These specifications exceed what caravan diagnostics require but provide confidence that readings mean something.
The CAT III 600V safety rating indicates the meter is designed and tested to withstand transient overvoltages typical of distribution-level circuits. Campsite hook-up supplies fall within CAT III territory. Budget meters often claim CAT III ratings without the internal protection circuitry, fusing, or input protection to survive a transient event. Fluke's rating comes with genuine high-rupture capacity fusing and metal oxide varistors providing surge suppression. If something goes wrong, the meter fails safely rather than explosively.
Specifications
Specification | Value |
AC/DC Voltage Range | 600V with 0.1mV resolution |
AC/DC Current Range | 10A (20A for 30 seconds) |
Resistance Range | 40 megohms with 0.1 ohm resolution |
Capacitance Range | 10,000 microfarads |
Frequency Range | 50kHz |
DC Voltage Accuracy | 0.5% + 2 digits |
Display | 6000-count digital with LED backlight |
Safety Rating | CAT III 600V |
Battery | 9V (approximately 400-hour life) |
Dimensions | 167 x 84 x 46mm |
Weight | 550g |
Operating Temperature | -10°C to +50°C |
Warranty | Three years |
Why It's Recommended
The price difference between the Fluke 117 and a budget multimeter reflects engineering that isn't visible on a specification sheet. Internal construction uses spark gaps and metal oxide varistors to clamp voltage transients before they reach the measurement circuits. High-rupture capacity ceramic fuses interrupt fault currents that would vaporise standard glass fuses, potentially turning the meter into a fragmentation hazard. Input protection survives accidental connection to 600V when set to the ohms range, a mistake that destroys lesser meters instantly.
True RMS measurement costs more to implement than average-responding circuits. The computational overhead requires better analog front-end components and more sophisticated processing. Budget meters claiming "True RMS" often deliver it only on certain ranges or with reduced accuracy. The Fluke 117 provides genuine True RMS across its full AC voltage and current ranges with consistent accuracy specifications.
Calibration stability matters for a tool purchased once and used for years. The Fluke 117 maintains its accuracy specifications across a temperature range of -10°C to +50°C, covering any realistic UK touring conditions. Budget meters often specify accuracy only at 23°C and drift significantly at temperature extremes. A reading taken in a cold caravan on a February morning remains meaningful.
The LoZ function addresses a genuine diagnostic problem. Ghost voltages from capacitive coupling confuse fault diagnosis, causing you to chase phantom faults while the real problem lies elsewhere. No budget meter offers this feature because it requires switchable input impedance with appropriate protection circuitry for both modes. For caravan wiring where space constraints force cables into close proximity, LoZ eliminates an entire category of misleading readings.
Non-contact voltage detection integrates functionality that would otherwise require a separate tool. Standalone voltage detectors cost £15-30 for reasonable quality, narrowing the effective price gap. More importantly, integration means the detection is always available without remembering to pack another device or rummaging through your toolbox.
Build quality determines whether the meter survives real-world use. The 117's overmoulded case absorbs impacts that crack rigid housings. The rotary switch uses positive detents that maintain position rather than drifting between settings. The battery compartment opens with a single captive screw without removing the protective holster. These details accumulate into a tool that remains functional after years of service rather than becoming unreliable after a few seasons.
For caravan electrical diagnosis, the Fluke 117 provides measurement capability that exceeds requirements while delivering the reliability and safety margins that justify confidence in your readings. Budget meters measure voltage. The Fluke 117 provides answers you can trust.
Rating
Overall Score: 4.5/5
Score Breakdown
Design: 5/5
Durability: 5/5
Ease of Use: 4/5
Value for Money: 4/5
Disclaimer
This review reflects our genuine opinions and experiences. Some of the links in this article are affiliate links, including Amazon Associate links. As an Amazon Associate, we earn from qualifying purchases. This means we may receive a small commission if you buy through these links, at no extra cost to you.
Product details, availability, and prices were accurate at the time of writing but may change without notice. Please check with the retailer for the latest information before making a purchase. Caravan Coach cannot be held responsible for differences between this review and the actual product or service you receive.
