Short answer: a CEMA 4 enclosure is a NEMA Type 4 enclosure wearing its old Canadian name, and that is how you order it. The Canadian Electrical Manufacturers Association (CEMA) wrote enclosure types in Canada; its successor EEMAC harmonized them with NEMA 250, and NEMA 250 is the document that survived. There is no CEMA rating chart to download, and there never will be again. For your client's line, buy a Type 4 enclosure, 4X stainless wherever hose water meets chemicals, and keep one line of written confirmation in the project file. Every stainless wall-mount box we build is rated NEMA 4X / IP66 by the manufacturer; not UL listed. Type 4X stops everything 4 stops plus corrosion, so one enclosure answers both readings of the spec.
Where the CEMA name comes from
The Canadian Electrical Manufacturers Association was Canada's trade body for electrical equipment, and it published its own enclosure type definitions. That work passed to the Electrical and Electronic Manufacturers Association of Canada (EEMAC), and the Canadian and US types were then harmonized, so a Type 4 meant the same construction and the same hose test in Toronto as in Toledo. The definitions live on in NEMA 250 and UL 50E in the US, and in the CSA C22.2 No. 94 enclosure standard in Canada, with UL and CSA as the certifying houses on each side of the border. EEMAC folded decades ago, which is why your search comes up empty: the chart was retired with the committee that wrote it.
Most CEMA 4 specs you will meet are that harmonization still echoing through a customer's standards library; the rest are typing slips, N-E-M-A rearranged into C-E-M-A. Both land on the same order: Type 4. If you want the full current set, the NEMA enclosure types guide walks all of them, from Type 1 indoors to 6P under water.
What Type 4 stops, and where 4X starts
NEMA 250 writes Type 4 for indoor and outdoor use: dusttight and watertight, proof against splashing and hose-directed water, and undamaged by ice forming on the outside. Type 4X adds corrosion resistance, and the addition is concrete. Table 5-1D of NEMA 250 and UL 50E gives 4X another 200 hours of salt spray, judged against an AISI 304 stainless specimen in the same chamber. That extra 200 h is the whole X, and it is the number to quote when someone asks what separates the two types. The NEMA 4 vs 4X vs IP66 comparison covers the gasket and latch detail that goes with it.
| Type | Stops | Corrosion test | Where you meet it |
|---|---|---|---|
| 3R | rain, sleet, external ice; vented and drained (NEC 314.15 allows 3-6 mm [1/8-1/4 in] openings) | none | pole gear, meters, cost-first outdoor |
| 4 | windblown dust, hose-directed water, external ice | none | general indoor and outdoor duty |
| 4X | everything 4 stops | extra 200 h salt spray vs a 304 specimen | food, pharma, coast, chemical washdown |
| 6P | everything 4X stops, plus submersion at depth for long periods | same 200 h test | sumps, pits, flood-prone yards |
NEMA's own conversion table maps Types 4 and 4X to IP66, and the IP66 test is specific: a 12.5 mm nozzle delivering 100 L/min, held 2.5-3 m [8-10 ft] away, for at least 3 min. IP66 says nothing about immersion, which is IP67 at 1 m [3.3 ft] for 30 min, and nothing about corrosion. In US installations, NEC 110.28 says an IP code cannot replace an enclosure type rating, so put both on the nameplate: Type 4X, IP66. The IP rating chart decodes the rest of the digits.
Who tests, who certifies, who rates
NEMA writes the type definitions; it never tested, certified or listed a single enclosure. The test documents are UL 50E in the US and the CSA equivalent in Canada, and a listing means the certifier ran that box's gasket, latch and walls through those tests and opened a file. A manufacturer rating means the maker builds to the type and answers for it: ours are rated NEMA 4X / IP66 by the manufacturer and are not UL listed. The small, real differences between UL and NEMA enclosure ratings live in pass marks like the salt-spray comparison, not in the type numbers, so a spec written in types is satisfied by a box rated to either document.
One fork matters in US workplaces. OSHA 29 CFR 1910.303(a) requires electrical equipment to be approved, and 1910.399 ties approval to a nationally recognized testing laboratory. When the inspector on your job wants a listing, that job needs a listed enclosure. The UL 50E vs NEMA 250 guide covers that fork end to end.
The one e-mail that settles the spec
Before you order, send one line: "The CEMA 4 enclosure types were harmonized into NEMA 250; we propose NEMA Type 4X (IP66) in stainless, which meets Type 4 and adds corrosion protection. Please confirm." One sentence out, one sentence back, and your file now holds the original wording, your interpretation and the client's acceptance. Ask for the client's view on the manufacturer rating in the same e-mail: most owners accept it once it is in writing, and the ones who want a listing tell you before the order instead of at commissioning. Skipping that exchange is the only expensive mistake in this story: an enclosure rejected at commissioning costs you the rebuild and the schedule, while the e-mail costs you ninety seconds. Order after the reply lands.
What a sealed box costs you in heat
Type 4 and 4X enclosures carry no louvers and no fan holes, so every watt you mount stays inside until the walls shed it. For stainless, use a wall heat transfer of 3.7 W/m²K, and hold inside air at 40 C [104 F] for drives and most electronics at 35 C [95 F] ambient.
Take a 16 x 14 x 8 in 316L enclosure: 0.406 x 0.356 x 0.203 m, so the surface is A = 2 x (0.406 x 0.356 + 0.406 x 0.203 + 0.356 x 0.203) = 0.60 m². It sheds 3.7 x 0.60 = 2.2 W per kelvin, so a 5 K rise carries 2.2 x 5 = 11 W. Now hang a 1.5 kW [2 hp] drive running at 97% efficiency: it dumps 1,500 x 0.03 = 45 W into the box. The rise is 45 / 2.2 = 20 K, putting inside air at 35 + 20 = 55 C, fifteen degrees past the drive's rating.
To hold a 5 K rise at 45 W you need 45 / 5 = 9 W/K, which is 9 / 3.7 = 2.4 m² of wall. A 48 x 36 x 10 in 316L enclosure has A = 2 x (1.219 x 0.914 + 1.219 x 0.254 + 0.914 x 0.254) = 3.31 m², so 3.7 x 3.31 = 12.3 W/K and a rise of 45 / 12.3 = 3.7 K, which is 39 C inside on a 35 C day. Outdoors, add the sun before you believe any of it: the outdoor enclosure heat gain walkthrough does that arithmetic, and the VFD enclosure sizing article sizes a drive panel end to end.
What to put on the order
| Order line | Write this | Why |
|---|---|---|
| Rating | NEMA Type 4X, IP66 (manufacturer rating) | covers the CEMA 4 reading and adds corrosion |
| Material | 316L near the coast, in food and pharma; 304 indoors and dry | chlorides and sanitizers |
| Size | from the heat check above | a sealed box cools through its walls |
| Glands | cable glands rated IP66 or better, one per cable | a gland sets the assembly's rating at its hole |
| Cutouts | cut by the builder from your drawing | keeps the gasket line whole |
| File | the client's CEMA line plus the confirmation e-mail | settles it at commissioning |
An IP54 gland on a 4X box makes an IP54 hole, because the weakest part sets the rating; what the panel keeps after you cut it lists the parts that do it. For the material split, the 304 stainless on-spec buying guide handles the dry-indoor case, and the 316L wall-mount enclosures section carries the washdown and coastal sizes.
Decision by case: indoor and dry, order 304 Type 4X. Hosed, coastal, food or pharma, order 316L Type 4X. The spec demands a listing, buy a listed enclosure, because ours are manufacturer-rated. The spec mentions submersion, that job wants Type 6P. Custom sizes and cutouts run through the enclosure selector and arrive delivered in 10 business days, counted from your order, or from your approval of the drawing for custom work.
Enclosures in this article
| Enclosure | Material | Outside H x W x D / display | Rating |
|---|---|---|---|
| 16 × 14 × 8 in | 316L stainless | 16 x 14 x 8 in | Rated NEMA 4X / IP66 by the manufacturer; not UL listed |
| 48 × 36 × 10 in | 316L stainless | 48 x 36 x 10 in | Rated NEMA 4X / IP66 by the manufacturer; not UL listed |
Questions
Is CEMA 4 the same as NEMA Type 4?
For ordering purposes, yes. The Canadian enclosure types were harmonized with NEMA 250 decades ago, so a spec written today means Type 4: dusttight, watertight, hose-directed water and external ice. Buy a Type 4 or 4X stainless enclosure and keep one written confirmation from the client in the project file.
Is NEMA 4 the same as IP66?
NEMA's conversion table maps Types 4 and 4X to IP66, whose test is a 12.5 mm nozzle at 100 L/min from 2.5 to 3 m for at least 3 min. IP66 covers neither immersion, IP67 is 1 m for 30 min, nor corrosion. In US installations NEC 110.28 makes the type number govern, so give both on the order.
Will a NEMA 4X enclosure satisfy a CEMA 4 spec?
Yes, and so will Type 6P, which stops everything 4X stops plus submersion. Type 4X adds the corrosion test over Type 4: another 200 hours of salt spray judged against an AISI 304 stainless specimen, per Table 5-1D of NEMA 250 and UL 50E. What fails the line is going down the scale: a vented Type 3R box holds up to rain but not to the 180-degree hose-directed water the Type 4 test applies.
Does this have anything to do with the Conveyor Equipment Manufacturers Association?
No. That CEMA writes dimensional standards for conveyor equipment and publishes no enclosure types. When an electrical spec says CEMA 4, it points to the old Canadian electrical association's Type 4, or to a transposed typing of NEMA 4. Either way the order is a Type 4 or 4X enclosure.
Do I need a UL listed enclosure for this job?
Only when the inspector or the owner asks for one, and many owners accept a manufacturer rating if you ask in the same confirmation e-mail that settles the CEMA wording. Ours are rated NEMA 4X / IP66 by the manufacturer and not UL listed, so a job that demands a listing needs a listed enclosure; decide which you are on before the order, not at commissioning.
