Industrial Digital Multimeters: Choose the Right Model for Your Environment

By Sean Anderson, Fluke Application Specialist

Imagine you’re on an oil rig, surrounded by salty sea spray and high winds. Or perhaps deep underground at a mine where dust threatens to impair your tools. In these environments, a standard digital multimeter (DMM) simply won’t cut it. That’s why selecting the right one that meets the stringent requirements for durability and safety that align with where you work is essential.

This guide evaluates how four standout Fluke DMMs—the 87V, 87V MAX, 28 II, and 28 II Ex—stack up for specific industrial conditions. Ultimately, these industrial digital multimeters all perform the same functions and offer the same level of precision, so what you need to know is precisely which DMM is best for your work environment.

Key Ratings and Certifications

Industrial settings are tough on tools. Drops are common; exposure to dust, water, or metal shavings can compromise performance. In some industries—like mining, oil and gas, or chemical processing—even a small spark could trigger an explosion. This section explains the key protective ratings and certifications that help you stay safe and productive.

• IP (Ingress Protection) Ratings: IP ratings classify a device’s ability to resist solids such as dust and liquids like water, based on the IEC 60529 standard. The rating is shown as “IPXX,” where the first digit (0–6) indicates protection against solid particles (like dust), and the second digit (0–9K) specifies water resistance. For example, IP67 denotes a fully dust-tight device that can withstand immersion in water up to a 1 meter for 30 minutes. These ratings originate from the International Electrotechnical Commission (IEC), which provides standardized testing procedures.
  
  Different industries have varying IP requirements:
  • Consumer electronics often target IPX7 or IPX8 for water resistance (as in smartphones and smartwatches).
  • Industrial equipment frequently demands a high IP rating (IP67 or IP68) for protection in harsh environments.
  • In the automotive sector, components typically require IP6X for dust plus IPX7 or IPX9K to handle exposure to road debris and high-pressure water.
  • The food and beverage industry commonly relies on IP69K for equipment that must endure intense washdowns and steam cleaning
• Drop-Test Ratings: Drop testing evaluates how well a digital multimeter—or any device—survives accidental impacts and remains functional. Typically, the device is dropped from a specified height onto a hard surface to assess external damage and internal component integrity. Fluke performs in-house tests based on recognized standards and use third-party labs to verify the accuracy of these results. The resulting drop-test rating, expressed as a drop height, guides users on overall robustness, indicating how easily the unit can handle tough work environments.
  
  For instance, a 4-meter drop test rating means the meter was tested from that height multiple times without losing accuracy or compromising user safety. Different industries adhere to various drop-test references. Consumer devices often align with IEC guidelines, while industrial-grade equipment may follow IEC 61010 and related IEC 60068 series for mechanical stress testing. Ultimately, a drop-test rating is a practical benchmark of durability and reliability, ensuring the device continues operating safely even after the inevitable knocks and falls of daily use.
• Input Alert System: The Fluke input alert system enhances user safety by warning when test leads are connected to the wrong jacks for the selected function. By electronically monitoring lead placement, the system detects mismatches and provides both an audible beep and a visual warning on the display. This feature helps prevent blown fuses and potential damage to the meter. Beyond protecting the tool from misuse, it safeguards the operator and surrounding equipment from hazards caused by incorrect configurations.
• Safety Certifications: Independent labs like UL certify our multimeters for electrical and mechanical safety, ensuring protection against shock, mechanical hazards, and fire under normal conditions.
  
  However, specialized certifications like IECEx confirm that devices operate without generating sparks or heat capable of igniting flammable atmospheres, making them suitable for volatile areas. In mining, agencies such as MSHA, Mine Safety and Health Administration in the United States, require further testing to guard against explosions fueled by coal dust or methane. Together, these certifications assure users that their instruments meet rigorous standards for both every day and high‐risk environments.
• Intrinsic Safety: Intrinsic Safety (IS) is a protection method that prevents electrical equipment from igniting flammable gases, vapors, or dust by limiting energy levels. IECEx is a key certification body that ensures equipment meets international safety standards through design evaluation and testing.
  
  Industries such as oil and gas, chemical manufacturing, mining, pharmaceuticals, and power generation rely on intrinsic safety to maintain safe operations. Common intrinsically safe components include sensors, communication devices, and lighting. IS enhances safety and ensures regulatory compliance for managing explosive environments.

Comparing Industrial Digital Multimeters

Fluke 87V (IP30, 1-Meter Drop Test)

• Use case: Routine industrial applications with limited exposure to dust and moisture.
• Key advantages: High measurement accuracy, straightforward interface, standard lead detection system.
• Why choose the Fluke 87V: A more cost-effective solution for technicians in relatively controlled settings.
  • Real-world example: An industrial service electrician in a climate-controlled aerospace manufacturing plant that doesn’t require full waterproofing.

Fluke 87 V MAX (IP67, 4-Meter Drop Test)

• Use case: Rugged industrial settings prone to water spray, heavy dust, or multiple drops.
• Key advantages: Fully sealed against dust and moisture (IP67), buoyant holster, glow-in-the-dark buttons, and upgraded lead detection.
• Why choose the Fluke 87V MAX: Provides peace of mind if you frequently climb ladders, work outdoors, or handle tasks in tough environments.
  • Real-world example: A maintenance technician at a steel mill or foundry, where dust, metal shavings, and frequent drops demand the Fluke 87V Max’s IP67 seal and 4-meter durability.

Fluke 28 II (IP67, 3-Meter Drop Test, MSHA-Certified)

• Use case: Mining and other operations where explosive dust and harsh conditions are a concern.
• Key advantages: MSHA certification ensures safe use in mines. Offers full dust and water protection, extra durability, and upgraded lead detection.
• Why choose the Fluke 28 II: Dependable performance underground or in high-dust settings that could affect lesser equipment.
  • Real-world example: A maintenance supervisor at a mine who needs a durable meter that won’t ignite explosive dust.

Quick Industrial Digital Multimeter Product Comparison Table

Below is a concise comparison of each model’s features and the industries they best serve.

Compare Industrial Digital Multimeters by Key Environmental Considerations

IP Ratings

• Fluke 87V (IP30): Basic dust resistance and minimal water protection. Best for controlled industrial settings with moderate exposure to contaminants.
• Fluke 87V MAX, 28 II, 28 II Ex (IP67): Fully dustproof and waterproof (up to 1 meter, 30 minutes). Ideal for outdoor or extremely dusty/wet locations.

Takeaway: If your job site is prone to heavy dust or water exposure, choose a model with IP67.

Drop-Test Ratings

• Fluke 87V: Withstands drops up to 1 meter—adequate for routine tasks in relatively safe environments.
• Fluke 87V MAX, 28 II, 28 II Ex: Survive drops up to 3 meters—excellent for elevated, high drop risk, or outdoor work.

Takeaway: If your DMM is likely to take a tumble from ladders or scaffolding, go with a 3 or 4-meter drop rating.

Lead Detection System

• Fluke 87V: Standard system can be affected by metal dust or debris, occasionally causing false alerts.
• Fluke 87V MAX, 28 II, 28 II Ex: Upgraded system remains accurate even in debris-laden conditions.

Takeaway: Frequent exposure to metal shavings or dust? The upgraded lead detection in the MAX, 28 II, and 28 II Ex models keeps you on track.

Safety Certifications

• Fluke 28 II: MSHA-certified, making it safe for mining environments with explosive dust.
• Fluke 28 II Ex: Intrinsically safe with ATEX, IECEx, and CSA approvals—crucial for oil and gas, chemical plants, and other explosive atmospheres.

Takeaway: If you need to comply with specific industry regulations—especially in mining or locations subject to flammable/explosive gases—look for MSHA or intrinsic safety certifications.

Spotlight: The Fluke 28 II Ex and Intrinsic Safety

Among all Fluke DMMs, the 28 II Ex stands out for intrinsic safety—that is, it’s designed to eliminate the risk of ignition in flammable or explosive atmospheres. This is accomplished through specialized construction methods (such as potted circuitry and static-resistant holsters) and rigorous testing to ensure no spark or excessive heat can be generated under normal or fault conditions.

What is ‘Intrinsic Safety’?

Intrinsic safety is a protection technique used in potentially explosive atmospheres, such as refineries, chemical plants, and oil and gas platforms. The principle: even in the event of a fault, the device cannot release enough electrical or thermal energy to ignite a hazardous mixture.

Key Terms:

• Ex ia: Indicates the highest level of intrinsic safety (two-fault safety).
• IIC: Gas group including hydrogen and acetylene (the most explosive gases).
• T4: Temperature class ensuring the device’s maximum surface temperature stays below 135 °C (275 °F), preventing ignition of flammable substances.
• Gb or Ma: Defines the equipment protection level for gas (Gb) or mining applications (Ma).

Fluke 28 II Ex: Certified Around the Globe

The 28 II Ex boasts multiple certifications, each reflecting compliance with specific regional or international intrinsic safety standards:

1. IECEx (International Electrotechnical Commission System for Certification to Standards Relating to Equipment for Use in Explosive Atmospheres)
   • Marking: Ex ia IIC T4 Gb/Ex ia I Ma
   • Meaning:
     • Ex ia: The meter is intrinsically safe for use in explosive atmospheres
     • IIC: Suitable for hydrogen, acetylene, and carbon disulfide the most flammable gas group
     • T4: Maximum surface temperature under 135 °C.
2. Gb/Ma: “Gb” is equipment protection level for gases in Zone 1 locations, “Ma” indicates device is suitable for use in underground mines. Protected up to two faults. ATEX (European Union Directive 2014/34/EU)
   • Marking: II 2G Ex ia IIC T4 Gb/I M1 Ex ia I Ma
   • Meaning:
     • II 2G: Category 2 equipment, suitable for Zone 1 or Zone 2 areas
     • Ex ia IIC T4: Same intrinsic safety definition as IECEx, adapted for EU norms
     • I M1 Ex ia I Ma: Approved for mining applications at the highest protection level (M1). Protected up to two faults.
3. NEC/CEC (North America: National Electrical Code / Canadian Electrical Code)
   • Marking: Class I, Division 1, Groups A,B,C,D T4; Class I, Zone 1, AEx ia IIC T4; Ex ia IIC T4
   • Meaning:
     • Class I, Division 1, Groups A,B,C,D: Safe for all gas groups from the most flammable gases like acetylene to less flammable like propane. Division 1 means flammable gases are present under normal operating conditions.
     • Class I, Zone 1: Same concept as Division 1 but using international Zone-based classification.
     • AEx ia IIC T4: U.S. adoption of intrinsic safety, aligning with ATEX/IECEx conventions.
4. PCEC (China)
   • Marking: Ex ia IIC T4 Gb
   • Meaning:
     • Similar to IECEx, recognized in China for verifying intrinsic safety in the highest gas group (IIC) with T4 temperature classification.
5. Simtars (Australia)
   • Marking: Ex ia I Ma
   • Meaning:
     • I Ma indicates the device is safe for mining applications.
6. IEx (Brazil)
   • Marking: Ex ia IIC T4 Gb
   • Meaning:
     • Equivalent to IECEx standards, confirming compliance within Brazil’s regulatory framework.

Why So Many Certifications?

Each region or country has its own regulatory bodies and standards for explosive atmospheres. By holding these certifications, the 28 II Ex can be used legally and safely in virtually any major industrial region worldwide, most notably in the oil and gas sector, but also in chemical manufacturing, paint and coatings, pharmaceuticals and more.

Practical Maintenance for Industrial Digital Multimeters

1. Regular cleaning: Keep input jacks free of dust, metal shavings, and moisture. This is especially important if you’re working in debris-heavy environments.
2. Fuse replacement: For models like the 28IIEX, only use manufacturer-approved potted fuses to maintain intrinsic safety.
3. Battery checks: Replace batteries in a clean, dry area to protect internal circuitry from contaminants.
4. Calibration: Stick to your organization’s calibration schedule, especially if you work in regulated industries.

Conclusion

Choosing the right industrial digital multimeter means matching the instrument’s durability, safety certifications, and capabilities to your specific environment. Fluke offers a robust lineup:

• Fluke 87V: General industrial use in moderate conditions.
• Fluke 87V MAX: Enhanced durability for harsher settings with dust and water exposure.
• Fluke 28 II: MSHA-certified for mining and other dust-prone environments.
• Fluke 28 II Ex: Intrinsically safe for oil and gas, chemical plants, and any location with flammable or explosive materials.

By investing in the correct model, you ensure safer operation, reduce downtime, and keep critical processes running smoothly—even in the most demanding conditions.

About the Author

Sean Anderson has been a Product Application Specialist at Fluke since 2024, drawing on his AD01 Electrical Administrator background and power systems knowledge to deliver comprehensive support and expert guidance for users of the multimeter, clamp meter, and oscilloscope product lines. Since joining Fluke, Sean has focused on customer-facing research to assist in developing innovative new products and educational resources for core electrical test and measurement tools. With a commitment to customer satisfaction, great user experience, and clear communication, he continues to empower professionals in the field through hands-on service and support. Connect with Sean on LinkedIn.