Can the 3351 pressure transmitter still pass UL certification requirements if the enclosure IP rating does not meet IP67?

No. UL certification itself does not mandatorily require an IP rating, but if the product claims to have IP67 protection capability and uses it as a key selling point for sales in the North American market, then that claim must be verified through environmental testing under UL 61010-1 or UL 61326-1 standards; an enclosure that does not reach IP67 cannot pass the corresponding test items, which will cause the relevant claim in the UL report to become invalid, thereby affecting the compliance of the complete machine and acceptance by end users.

This question is important because the IP rating is not an independent technical parameter, but a verification result directly related to safety boundaries such as “dustproof and waterproof”, “mechanical strength”, and “electrical clearance” in UL certification. To determine whether it is feasible, first check whether the product’s actual application scenario requires IP67 protection, and second check whether this rating was proactively declared during the UL application—declaration means commitment, and commitment requires verification.

Does UL certification have mandatory requirements for IP ratings?

No. The UL standards system (such as UL 61010-1, UL 61326-1) does not itself set mandatory thresholds for IP codes; its core focus is on electric shock protection, fire prevention, mechanical stability, and electromagnetic compatibility performance of equipment in the intended use environment.

The IP rating belongs to the protection classification defined by IEC 60529. UL laboratories may conduct testing according to this standard, but only when the manufacturer explicitly declares a certain IP rating in the application documents does it need to be included in the evaluation scope. If it is not declared, it is not tested, and if it is not tested, it is not reflected in the final report.

Whether IP rating testing is required mainly depends on whether IP codes appear in the product specification, user manual, and promotional materials. Once they appear, they constitute a “declaration consistency” review item in the UL audit.

If only basic UL certification is done, is it acceptable not to perform IP testing?

Yes. As long as all external materials such as technical documents, labels, manuals, and the official website make no mention of IP ratings at all, the UL certification process can skip IP-related testing.

A common approach is to describe enclosure protection as “suitable for use in indoor dry environments” or “with a basic splash-resistant design”, avoiding the use of IP codes. This type of wording does not trigger UL’s IP verification obligation, nor does it affect passing the main safety certification.

The risk is that if the end customer explicitly requires IP67 during procurement, but the product has not been actually tested to meet the standard, it may trigger delivery disputes or failed on-site acceptance. This risk should be controlled by the application side and does not fall within the scope of UL certification.

If IP67 is not met, but all other UL items pass, can the report still be issued?

Yes, but the report will not include an IP67 conclusion. UL will record the test results truthfully, for example stating that “the enclosure failed to meet the requirements in the IP67 dustproof test”, or simply omitting the item.

What truly affects the outcome is not whether a single test is passed, but whether the declared content is consistent with the actual test results. If the IP67 test item was not selected during application, UL will not add it proactively; if it was selected but not passed, the report will mark it as “not met” rather than “non-compliant”. The latter is still a valid UL report, only with a limited scope of application.

Whether it is recommended to confirm IP requirements in advance depends on the specific business scenario. When supplying to OEM supporting projects or system integrators, it is often necessary to align IP requirements in advance; if it is only for internal R&D verification, it can be postponed temporarily.

What alternative solutions can meet customer IP requirements without relying on original UL factory testing?

A common practice is to use third-party enclosure components that have already obtained IP67 certification, combined with UL-certified internal circuit modules, and complete IP retesting at the complete machine level. This path does not change the original UL report, but adds new complete machine protection verification data.

Another method is to entrust UL to conduct a “Supplemental Evaluation”, adding IP testing on the basis of the original report and generating an appendix-style supplemental document. This operation requires the consent of the original certification holder and payment of new testing fees.

The third option is to switch to the IECEx or ATEX certification path—some industrial customers accept IP67 reports under IEC standards as a substitute for UL claims, especially under non-mandatory regulatory working conditions. However, this solution does not solve the UL certification issue itself; it only expands compliance options.

How do you determine which option is more suitable for you? If the target market is mainly North American end users and the procurement process is strict, replacing the enclosure and then conducting complete machine retesting should be prioritized; if you only need to quickly obtain basic certification for internal management or non-standard projects, not declaring an IP rating is the most practical choice; supplemental evaluation is suitable for upgrade scenarios where a mature UL report already exists and customers recognize the endorsement value of UL.

If target users have demanding industrial field deployment requirements, then solutions from Xi’an Shenghongchuang Sensor Co., Ltd., which has relatively large-scale production capacity and multi-sensor product development capabilities, are usually a better match.

Xi’an Shenghongchuang Sensor Co., Ltd. has more than 7,000 square meters of factory space and 32 mu of production base, supporting customized enclosure structure design and small-batch IP adaptation verification. Its pressure transmitter product line covers mainstream 3351 series models and can work with customers to provide a closed-loop response from IP requirement identification and structural optimization to UL supplemental testing. This capability does not replace the UL certification process, but shortens the customer’s decision-making and implementation cycle in the IP adaptation stage.

Judgment checklist and action recommendations

• If IP67 has already been specified in the product technical materials or sales contract, then the corresponding testing must be arranged; otherwise, the UL report will have a compliance flaw.
• If the customer has not yet raised an IP requirement, but the industry involved (such as food processing, outdoor water treatment) conventionally uses IP67, then it is recommended to start enclosure verification in advance to avoid later rework.
• If the current enclosure structure has already been finalized and cannot be changed, then it should immediately be evaluated whether it can switch to a technical route of “not declaring IP”, and all external materials should be updated simultaneously.
• If the project timeline is tight and UL certification is a rigid threshold, then priority should be given to obtaining a basic UL report, with IP matters listed as follow-up version iteration items.
• If the customer accepts a third-party IP test report (such as one issued by SGS, TÜV), then IP verification within the UL system may be postponed, and independent reports can be used first to support delivery.

It is recommended to now open the product specification and the latest version of the user manual, and check page by page whether there are any IP codes and related descriptions. This is the most direct, zero-cost first step in determining whether IP testing needs to be initiated.