Common Mistakes When Specifying IP67, IP68, or NEMA 6P Enclosures

Specifying IP67, IP68, or NEMA 6P enclosures rarely goes wrong because an engineer doesn't understand the rating. More often, problems begin when that rating is written into an RFQ or specification without enough detail. Common mistakes include requesting "IP68" without defining the required depth and duration, assuming a dual rating means both standards were independently verified, or accepting a manufacturer's rating claim without asking for supporting documentation.

Most engineers already know what IP67, IP68, and NEMA 6P mean. Surprisingly, that's usually not where specification errors occur. The real problems begin when assumptions replace requirements. Vague language, incomplete specifications, and missing verification can all lead to enclosures that technically satisfy the purchase order but fail to meet the actual demands of the application. By the time those issues are discovered, the equipment has often already been installed.

Common specification mistakes include:

• Naming a rating without defining the actual environmental conditions it must withstand

• Assuming a dual rating means both standards were independently tested and verified

• Accepting a rating claim without requesting supporting test documentation

For detailed explanations of each rating, see IP67 Enclosure Rating: Definition, Requirements, and When to Specify It, IP68 Electrical Enclosures and Junction Boxes, and NEMA 6 vs NEMA 6P: Differences in Submersible Enclosure Protection.

Mistake 1: Specifying IP68 Without Defining Depth and Duration

One of the easiest mistakes to make is assuming IP68 describes the same level of protection from one manufacturer to the next. It doesn't. Unlike IP67, IP68 leaves the submersion depth and duration to the manufacturer, so simply specifying "IP68 required" leaves room for very different interpretations.

Instead of relying on the rating alone, define the actual conditions the enclosure must withstand.

A complete specification should include:

• Required submersion depth (feet or meters)

• Required submersion duration (hours or continuous exposure)

• Water type, including freshwater, saltwater, or chemically treated water

• Any environmental conditions that could affect long-term performance

Why this matters:

• Two manufacturers can legitimately offer IP68 enclosures tested to different depths and durations

• A specification that only says “IP68” tells the manufacturer which rating you want, but not what performance the application requires

• Leaving those details open to interpretation increases the risk of receiving an enclosure that technically meets the specification but doesn’t meet the demands on the installation

Whether the enclosure is protecting equipment in a decorative fountain, a marina, or a wastewater lift station, the application should define the performance requirement, not the rating alone.

Mistake 2: Assuming a Dual Rating Means Both Conditions Were Independently Tested

Seeing a dual rating such as IP67/IP68 or NEMA 6P/IP68 can create a false sense of confidence. While these combinations may be accurate, they don’t automatically mean the enclosure was independently tested to every requirement of both standards. IP and NEMA are separate standards with different testing methods and acceptance criteria.

Before specifying a dual-rated enclosure, verify exactly what was tested.

Ask the manufacturer to provide:

• Documentation supporting each rating claimed

• The testing standards used for each rating

• Testing conditions, including depth, duration, and any manufacturer-defined parameters

• Whether testing was performed by an independent laboratory or documented through internal quality control procedures

Why this matters:

• Meeting one standard doesn’t automatically verify compliance with another

• A dual rating on a specification sheet doesn’t explain how each rating was achieved

• Verifying the supporting documentation before purchase helps eliminate assumptions during procurement and reduces the risk of selecting the wrong enclosure

A dual-rated enclosure can absolutely be the right solution. The key is understanding whether both ratings are supported by documented testing rather than relying on the label alone.

Mistake 3: Accepting a Rating Claim Without Requesting Testing Documentation

Not every enclosure advertised with an IP or NEMA rating is backed by the same level of documentation. Some manufacturers provide detailed test reports, while others simply state that the enclosure is “designed to meet” or “built to” a particular rating without offering supporting evidence.

If the application is critical, don’t rely on the rating alone. Ask how that rating was verified.

Before specifying an enclosure, request:

• Testing reports or certification documentation supporting the claimed rating

• The testing method and acceptance criteria used

• Whether production enclosures are tested or only a prototype or sample unit

• Any quality control procedures used to verify ongoing production consistency

Why this matters:

• A rating claim without documentation can be difficult to verify during procurement

• Reviewing test data helps confirm that the enclosure was evaluated under conditions similar to your application

• Documented testing provides greater confidence that production units will perform as expected, not just the original design

The goal is not to question every manufacturer’s claims. It is to make sure the documentation supports the level of protection your project requires before the enclosure is installed in the field.

Mistake 4: Treating All Submersible Applications the Same

Not every submersible application places the same demands on an enclosure. While two projects may both call for an IP68 or NEMA 6P rating, the operating conditions can be dramatically different. Water depth, exposure time, environmental contaminants, and installation location all influence long-term performance.

Instead of specifying the rating alone, consider the environment the enclosure will operate in.

Application factors to evaluate include:

• Temporary or prolonged submersion

• Freshwater, saltwater, or chemically treated water

• Flooding events versus continuous underwater operation

• UV exposure, temperature extremes, and freeze-thaw cycling

• Cable entry locations and potential leak paths

Why this matters:

• Two applications with the same enclosure rating may require very different enclosure designs

• Environmental conditions often have a greater impact on long-term performance than the enclosure rating itself

• Defining the actual operating environment helps ensure the enclosure is engineered for the conditions it will experience throughout its service life

An enclosure that performs well in a municipal lift station may not be the best choice for a coastal marina or a flood-prone transportation installation. The more closely the specification matches the application, the more reliable the long-term performance is likely to be.

Mistake 5: Overlooking Cable Entry Points and Seal Integrity

Even the best enclosure can fail if the cable entries aren't designed and installed for the same environmental conditions as the enclosure itself. Gaskets, doors, and seams often receive the most attention, but improperly sealed cable penetrations are one of the most common paths for water intrusion.

A complete specification should address the entire enclosure system, not just the enclosure body.

Include requirements for:

• Cable glands or cord grips with ratings appropriate for the application

• Unused openings sealed with approved plugs

• Proper installation torque for cable glands and fittings

• Compatible sealing materials for the operating environment

• Periodic inspection and maintenance of cable entry seals when applicable

Why this matters:

• Water typically enters through the weakest point in the enclosure system, which is often a cable entry rather than the enclosure itself

• An IP68 or NEMA 6P enclosure can lose its environmental protection if cable glands, conduit hubs, or plugs are incorrectly installed

• Specifying the entire sealing system helps ensure the installed enclosure performs as intended

A properly rated enclosure is only part of the solution. Long-term reliability depends on every penetration maintaining the same level of environmental protection as the enclosure itself.

For more information on protecting enclosure penetrations, see Sealing Cable Entries and Cable Glands for Submersible Electrical Enclosures.

Mistake 6: Specifying a Rating Without Accounting for Installation and Maintenance Access

A specification can name the correct rating, materials, and sealing requirements and still fall short if it doesn't account for how the enclosure will actually be installed and serviced over its lifetime. Confined mounting locations, limited clearance, and infrequent access can all affect long-term sealing performance in ways the rating itself doesn't address.

A complete specification should also define:

• Mounting location and available clearance for installation and future service

• Access requirements for periodic inspection, gasket replacement, or cable rework

• Whether the installation site allows for proper torque application and reseating of fasteners during maintenance

• Environmental conditions the enclosure will face specifically during service, not just during normal operation

Why this matters:

• An enclosure that is difficult to access is less likely to be properly maintained over its service life

• Improper reassembly after service is a common cause of field failures in otherwise correctly specified enclosures

• Addressing access requirements at the specification stage reduces the risk of maintenance-related sealing failures later

Before You Send the RFQ: A Practical Checklist

1. Confirm depth, duration, and fluid type are stated explicitly for any IP68 or NEMA 6P requirement

2. Require independent test documentation for every rating claimed, especially dual ratings

3. Avoid “or equivalent” language for the primary rating requirement

4. Specify cable entry and accessory sealing requirements separately from the enclosure body rating

5. Request material and finish specifications alongside the rating, not as an afterthought

For a buyer-focused checklist specific to NEMA 6P procurement, see Questions to Ask Before Buying a NEMA 6P Enclosure.

How NEMACO™ Can Help

NEMACO™ works directly with engineers and procurement teams to eliminate ambiguity before it becomes a field problem. Every claimed rating is backed by documented, independently verified test data, including ISO 17025 calibrated instrumentation, so specifications can be written and confirmed with confidence rather than assumptions. Enclosures are American made and UL Listed, with material and sealing requirements addressed as part of the same conversation as the rating itself.

NEMACO™ products are backed by a 5 to 15-year warranty depending on the configuration, reflecting confidence in how each enclosure is specified, built, and verified from the beginning.

Frequently Asked Questions (FAQs)

Why isn’t “IP68” alone enough to include in a spec?

Because IP68 doesn’t have a fixed depth or duration. Conditions are defined by the manufacturer, so a spec that only states “IP68” without depth, duration, and fluid type leaves the actual performance requirement undefined.

Does a product listed as “IP67/IP68” mean both ratings were independently tested?

Not necessarily. Passing one test doesn’t automatically qualify a product for the other. Confirm independent test documentation exists for each rating claimed.

What is the risk of writing “NEMA 6P equivalent” instead of requiring the actual certification?

“Equivalent” implies similarity, not verification. A vendor could supply a product that approximates NEMA 6P performance without being tested and certified to the standard itself.

What documentation should I request to verify a rating claim?

Request calibration test data, such as ISO 17025 documentation, along with the specific UL designation, Listed or Certified, that applies to the product.

Why should cable entries be specified separately from the enclosure body?

An enclosure body can pass its rated test while cable entries and glands remain the actual failure point. Specifying entry point sealing separately closes that gap.

Does specifying a rating also cover corrosion resistance?

Not automatically. Ingress ratings like IP67 and IP68 don’t address corrosion at all, NEMA 6P’s corrosion resistance depends on materials and finish, not the rating alone.