Industrial enclosure

01

Choose the NEMA Type or IP code for the location

NEMA's summary of NEMA 250-2003 defines enclosure Types by the protection they give when completely and properly installed. Type 1 is for indoor use against access to hazardous parts and falling dirt. Type 4 is for indoor or outdoor use against windblown dust, rain, sleet, snow, splashing and hose-directed water, and is undamaged by ice forming on it; Type 4X adds protection against corrosion. Type 12 is for indoor use, built without knockouts, against falling dirt and circulating dust, lint, fibres and flyings, and dripping and light splashing; Type 12K is the same with knockouts; Type 13 adds oil and coolant. [1]

The same document explains that IEC 60529 rates enclosures with IP plus two numerals — the first for protection of persons and against solid objects, the second against water — but does not cover mechanical damage, explosion, condensation, corrosive vapours, fungus or vermin, while NEMA 250 tests for corrosion, rust, icing, oil and coolants. NEMA Types therefore meet or exceed an associated IP code, but an IP code cannot be converted back into a NEMA Type. [1]

Masion lists enclosures by IP code from IP44 to IP68 and by NEMA Type from 1 to 13, including 3R, 3X, 4, 4X, 6P and 12. [3]

Give the supplier the location (indoor, outdoor, washdown, corrosive, hazardous), the required NEMA Type or IP code and certification, the equipment and HMI to be housed, heat load and ventilation or cooling, dimensions, door and window, cable entries and glands, mounting (wall, floor, pedestal, arm), material and finish, and quantity.

02

Pick the material, wall thickness and openings

Weimiao lists 304 and 316 stainless steel, anodized aluminium and powder-coated carbon steel, with tolerance control down to ±0.07 mm; 316/316L stainless enclosures of 3–6 mm thickness for offshore, oil and gas and marine environments; ATEX/IECEx explosion-proof enclosures; enclosures meeting IP66/IP67, CE, UL, RoHS and IEC requirements; and in-house powder coating and integration of PLC and VFD mounting, ventilation and cable routing. [2]

The pictured enclosure is a floor-standing stainless steel HMI housing on legs with a sloped top, a hinged door with a large window, a key lock and cable glands entering from below. NEMA states that its Types describe the protection given when the enclosure is completely and properly installed, so ask how the window, cut-outs, glands and vents were included in the rating. [1]

Editorial calculation: a 3 mm to 6 mm wall range is a twofold difference in thickness and in sheet mass per square metre for the same steel. [2]

03

Check the empty-enclosure standard behind a switchgear housing

IEC 62208 covers "empty enclosures, as provided by the enclosure manufacturer, prior to the incorporation of switchgear and controlgear components by the assembly manufacturer". The 2023 third edition sets definitions, classifications, characteristics and test requirements for enclosures used as part of assemblies built to the IEC 61439 series, with a rated voltage that does not exceed 1 000 V AC or 1 500 V DC, for indoor or outdoor use. [4]

The abstract places the split of responsibility at the empty housing: the enclosure maker supplies the box, and the assembly manufacturer adds the switchgear and controlgear. When a control panel shop buys a stainless or painted steel cabinet for a low-voltage panel, ask whether the empty enclosure was tested to IEC 62208 and which edition the test report cites, because a report against the 2011 text predates the IEC 61439-1:2020 changes. [4]

IEC 62208 does not replace the NEMA Type or IP code on the order. NEMA describes its Types as the protection given by a completely and properly installed enclosure [1], and suppliers such as Masion quote IP and NEMA ratings side by side [3]. Keep the rating line and the IEC 62208 line as two separate entries on the specification.

Editorial calculation: the 2011 edition was in force from 19 August 2011 to 1 June 2023, a span of just under 12 years before edition 3 replaced it. [4]

Values are taken from the Standard Norge catalogue pages for IEC 62208 editions 2 and 3; the full standard text was not reviewed.

04

Stainless consoles, NEMA/IP sheet-metal boxes and outdoor cabinets

Ask any supplier for the NEMA Type or IP code and the test or certificate behind it, material grade and thickness, finish, gasket material, door and lock, window material, cut-outs and cable entries, mounting plate, dimensions and weight, thermal management, and drawings for approval.

05

Body, door gasket, window cut-out and glands

Window, cut-out and gland rows are the openings to check against the rating, since NEMA's Types describe a completely and properly installed enclosure. [1]

06

Published values for rating, material and wall; the rest comes from your drawing

Dimensions, mounting, cable entry and weight carry no published figure here because they follow from the equipment you house; give them on the drawing you send.

07

Send the equipment, location and rating data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Equipment: [HMI; controls; heat load]
Location: [indoor; outdoor; washdown; corrosive; hazardous]
Rating: [NEMA Type; IP code; certificate]
Material: [304; 316; steel; aluminium; thickness]
Openings: [window; cut-outs; cable entries; vents]
Mounting: [wall; floor; pedestal]
Size: [W×H×D]
Quantity: [units]

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