A supplier lists an enclosure as IP66, and your import fills a NEMA Type 4X filter from a conversion chart. Buyers can now find that enclosure under a rating the supplier never stated. For industrial ecommerce teams, the fix is to store IP codes and NEMA Types separately, preserve the evidence for each, and stop a comparison chart from becoming a new product claim.
Key takeaways
Keep IP and NEMA values in separate fields. A rating in one system does not establish the same product's declared rating in the other.
Retain every supported rating and its conditions for the exact part. Do not replace several NEMA Types with one supposed highest value.
Leave an unsupported field unresolved. A blank NEMA field is a supplier question, not permission to convert an IP code.
Start with the rating system the supplier actually names
IP codes describe degrees of protection provided by enclosures under IEC 60529. In the familiar two-numeral code, the first numeral concerns access to hazardous parts and entry of solid foreign objects. The second concerns harmful water ingress. Keep the complete code supplied for the part, including any additional letters, rather than stripping it down to a number. IEC 60529; NEMA enclosure comparison
NEMA Types address their own sets of enclosure requirements. Depending on the Type, these include conditions beyond the IP classification, such as corrosion or external icing. The tests also differ. NEMA's published guidance therefore does not allow an IP code to establish an equivalent NEMA Type. Its 2005 comparison works in the NEMA-to-IP direction for specified requirements; it cannot be read in reverse. NEMA enclosure comparison; NEMA enclosure FAQs
That distinction should change your mapping rule. If the supplier provides only IP66, store IP66. Do not manufacture a NEMA value to make the record look complete. If your team needs a cross-reference for technical review, keep it separate from the supplier's declared product ratings and label its basis.
One enclosure can have more than one supported rating
Hammond's part page for 1555A2GY provides a useful example. Its part attributes list IP68 and NEMA 4, 4X, 6, 6P, 12 and 13. These are separate source values for one named part, so the catalog can preserve both the IP code and the stated set of NEMA Types. There is no need to derive either from the other. Hammond 1555A2GY
This is why a single numeric field is a poor fit for NEMA Types. Taking the largest number would turn the example into 13 and discard 4X and 6P. Store the supported set without ranking the labels as a single scale. NEMA's FAQ allows multiple Type designations when the applicable requirements are met. NEMA enclosure FAQs
Test the mapping with three supplier records
Suppose your team is cleaning up three enclosure listings. The supplier material supports the following values for the named parts. The table shows how to represent that evidence, not a rating assessment of real products.
| Supplier record | IP field | NEMA Type field | Decision before publication |
|---|---|---|---|
| Box A lists IP66 only | IP66 | Unresolved | Ask for a NEMA declaration only if the destination or buyer requirement needs it. |
| Box B lists NEMA Type 4X only | Unresolved | 4X | Keep the stated Type. Do not present a derived IP code as supplier-declared. |
| Box C lists IP66 and NEMA Types 4, 4X and 12 | IP66 | 4; 4X; 12 | Retain each value and any conditions stated for it. |
On your site, a filter labeled "NEMA Type 4X" should return Box B and Box C on this evidence. It should not return Box A merely because a mapping table pairs IP66 with 4X. A separate IP66 filter can return Box A and Box C.
For a comparison table, display an empty field as "Not stated in the source reviewed" when that wording helps buyers. Avoid "None" or "Not rated" unless the source actually supports that conclusion. Internally, distinguish a missing value from a conflicting one so the next reviewer knows what to resolve.
Keep the source and conditions with each value
Behind each rating, record the exact manufacturer part number, source document or URL, stated standard and edition, and any conditions. Add the date checked so another reviewer can find the evidence behind a later update.
Do not fill in an edition from memory. Supplier documents can use older standard names, and the current ANSI catalog lists ANSI/NEMA EN 10250-2026. Preserve what the source says instead of rewriting every NEMA reference to one edition. A standards update alone does not establish that a particular product was evaluated to the newer edition. ANSI NEMA EN 10250 2026
Conditions need the same care. NEMA's FAQ gives "NEMA 4X Only When Door Closed" as an example of a conditional designation. If a supplier makes a comparable qualification, keep it attached to the value in the product page and review what a shortened filter or badge implies. Without that condition, the label could suggest that the same protection applies while the door is open. NEMA enclosure FAQs
Keep certification information separate too. A NEMA Type field records the classification supported by the source; it should not automatically produce a "NEMA certified" badge. NEMA develops standards and does not certify products. For the separate question of what a certification covers, see our guide to keeping UL claims tied to the right product. NEMA enclosure FAQs; UL claims in product catalogs
Check the filters and copy before reusing the mapping
Run the three-record example through the actual output your buyers will see. You are checking whether your data transformation added a claim, removed a qualification or attached a family-level value to the wrong part.
In filters, confirm the IP66-only record does not appear as a NEMA Type 4X match.
In comparison tables, confirm both systems have clear labels and unresolved values stay distinguishable from explicit negative claims.
In titles and descriptions, confirm a declared rating has not become a broader "waterproof" or installation-suitability promise.
In supplier updates, change only Box C's IP source value and check that its NEMA values are not recalculated as a side effect.
These are catalog quality checks. Choosing an enclosure for a particular installation still requires the applicable requirements and manufacturer instructions. A cleaner filter helps buyers find stated specifications; it does not approve the application.
Frequently asked questions
Are IP66 and NEMA Type 4X equivalent?
No. They belong to different classification systems with different requirements. NEMA's comparison guidance does not support converting an IP rating into a NEMA Type. Keep whichever values the evidence states for the exact part. NEMA enclosure comparison; NEMA enclosure FAQs
Can I use a NEMA to IP chart to fill missing catalog fields?
Use a comparison only within its stated scope and direction. For catalog publication, distinguish a technical cross-reference from a manufacturer-declared rating. The workflow above leaves the declared-value field unresolved until applicable product evidence supports it. NEMA enclosure comparison
Why do some products list both IP and NEMA ratings?
A product may have evidence for both systems. Hammond's 1555A2GY page, for example, lists IP68 separately from its NEMA Types. Record both rather than assuming that one was calculated from the other. Hammond 1555A2GY
How should I store several NEMA Types for one part?
Retain the supported values as a set, such as 4, 4X and 12, with their source and conditions. NEMA permits multiple Type designations when the requirements are met. Avoid a rule that selects only the largest number. NEMA enclosure FAQs
Does a missing NEMA rating mean the product is not rated?
Not necessarily. It means the source you checked did not establish that value. Keep the evidence gap visible internally and request part-specific information when needed. Do not infer either a positive rating or a failed assessment from an empty field.
Is a NEMA Type the same as a NEMA certification?
No. NEMA says it neither tests nor certifies products. A manufacturer may declare conformity or seek third-party certification. Store the actual declaration and any separate certification evidence without turning the Type label into a certification claim. NEMA enclosure FAQs
Can every product in a series inherit the same ratings?
Only when the source establishes that the rating applies to those parts and configurations. Check model exceptions before copying a family-level rating. Hammond's 1555 series page, for example, states a Type-rating exception for one part. A series heading alone would miss that restriction. Hammond 1555 series
How this gets done in Merchkit
Bring one supplier file with mixed IP and NEMA labels to a Merchkit demo. Use the three-record test to evaluate how the catalog workflow can reduce repeated cleanup while keeping your team in control of published claims.
Set up separate rating fields. Review separate IP and NEMA attributes so buyers can compare the specification they actually need. Merchkit documents custom attributes; use the sample to confirm how the stated values and conditions would be represented. Merchkit custom attributes
Avoid repeating the same mapping work. Test the mapping once on IP-only, NEMA-only and dual-rated records before applying it more broadly. Identify which repeatable work can be simplified and which source differences still require a person.
Bring unresolved values to the reviewer. Ask how the reviewer would inspect the source behind a generated value, correct a false conversion and retain the unanswered question. Merchkit's review documentation describes examining results and their rationale; verify the behavior with your sample. Merchkit content review
Check the buyer-facing result. Compare the proposed filters, product-page specifications and channel copy with the approved records. Confirm that shortening the copy or updating one field does not invent a rating in the other system.
Book a demo with a supplier enclosure file to see which catalog steps your team can simplify and what it needs to keep under review. Book a Merchkit demo
