888-886-8185
8am-5pm PST

Technical Specifications for ABS Plastic and Polycarbonate Electrical Enclosures

BriefOverview

It's common to find metal electrical enclosures installed nearly everywhere you turn and used throughout a multitude of industries and applications. However, it suprises us even today, that many of our customers have only known metal to be the answer to many of their projects when in fact, Polycarbonate or Acrylnitrile-butadiene-styrene (ABS) enclosures are suprising contenders if not better for their applications.

Both ABS Plastic and Polycarbonate electrical enclosure material offer excellent performance at both a material and application level and can be a suitable substitue over stainless steel, metal or even fiberglass enclosures depending on the application. Check out some of their higher-level benefits and drawbacks below before we get to the nitty-gritty.

Material
Cost
Weight
Chemical Resistance
Corrosion Resistance
Impact Resistance
Heat Dissipation
Heat Absorption
Polycarbonate
Medium
Low
High
Very High
Very High
Low
Very High
ABS
Low
Low
High
Very High
Medium
Low
Very High
Fiberglass
High
Medium
High
Very High
High
Low
Very High
Painted Steel
Medium
Very High
High
Medium
Low
Medium
Medium
Stainless Steel
Very High
Very High
Very High
High
Low
Medium
Medium
Aluminum
Very High
High
Very High
High
Low
Very High
Low

*This is a general guide. The specific environment should be taken into consideration when selecting an enclosure.

Materials
Polycarbonate
ABS
FRP
Stainless Steel
Steel
Acetic Acid (10%)
Satisfactory
Limited
Satisfactory
Unsatisfactory
Unsatisfactory
Acetone
Unsatisfactory
Unsatisfactory
Unsatisfactory
Satisfactory
Satisfactory
Aluminum Chloride (10%)
Satisfactory
Satisfactory
Satisfactory
Satisfactory
Unsatisfactory
Aluminum Sulfate (10%)
Satisfactory
Satisfactory
Satisfactory
Satisfactory
Unsatisfactory
Ammonia Gas
---
---
Limited
Satisfactory
Satisfactory
Ammonium Chloride
Satisfactory
Satisfactory
Limited
Moderate
Unsatisfactory
Ammonium Hydroxide (10%)
Unsatisfactory
Moderate
Limited
Satisfactory
Unsatisfactory
Ammonium Nitrate (10%)
Unsatisfactory
---
Limited
Satisfactory
Satisfactory
Ammonium Phosphate (10%)
Satisfactory
Satisfactory
Satisfactory
Satisfactory
Unsatisfactory
Ammonium sulfate
---
Satisfactory
Satisfactory
Moderate
Unsatisfactory
ASTM #1 Oil
Moderate
Limited
---
Satisfactory
Satisfactory
ASTM #3 Oil
Moderate
Limited
---
Satisfactory
Satisfactory
Axle Grease
Moderate
Limited
---
Satisfactory
Satisfactory
Boric Acid (10%)
Satisfactory
Satisfactory
Satisfactory
Satisfactory
Unsatisfactory
Calcium Chloride (10%)
Satisfactory
Moderate
Satisfactory
Limited
Limited
Calcium Hydroxide (10%)
Satisfactory
---
Unsatisfactory
Moderate
Satisfactory
Carbolic Acid (25%) Phenol
Unsatisfactory
Unsatisfactory
Limited
Moderate
Unsatisfactory
Carbon Tetrachloride
Unsatisfactory
Unsatisfactory
Satisfactory
Moderate
Unsatisfactory
Chlorine (water) 5-10 ppm
Satisfactory
Satisfactory
Satisfactory
Moderate
---
Chrome Plating Solution
Satisfactory
Limited
---
Unsatisfactory
Unsatisfactory
Chromic Acid
---
Satisfactory
Satisfactory
Moderate
Unsatisfactory
Citric Acid (10%)
Satisfactory
Unsatisfactory
Satisfactory
Satisfactory
Unsatisfactory
Copper Sulfate
---
---
---
Moderate
Unsatisfactory
Cutting Fluid (Norton 205)
Satisfactory
Limited
---
Satisfactory
Satisfactory
Ethyl Alcohol
Moderate
Moderate
Moderate
Satisfactory
Satisfactory
Ethylene Glycol
Satisfactory
Satisfactory
Satisfactory
Satisfactory
Satisfactory
Ferric Chloride
Satisfactory
Satisfactory
Satisfactory
Unsatisfactory
Unsatisfactory
Formaldehyde
---
Satisfactory
Satisfactory
Satisfactory
Satisfactory
Formic Acid
Satisfactory
Unsatisfactory
Limited
Satisfactory
Unsatisfactory
Fuel Oil (#2)
Satisfactory
Unsatisfactory
Satisfactory
Satisfactory
Satisfactory
Gasoline
---
Unsatisfactory
Satisfactory
Satisfactory
Satisfactory
Glycerin
---
Limited
Satisfactory
Satisfactory
Satisfactory
Hydraulic Brake Fluid
Unsatisfactory
Unsatisfactory
---
Satisfactory
Satisfactory
Hydraulic Oil
Moderate
Unsatisfactory
Satisfactory
Satisfactory
Satisfactory
Hydrochloric Acid (10%)
Satisfactory
Satisfactory
Limited
Unsatisfactory
Unsatisfactory
Hydrofluoric Acid (20%)
Moderate
Limited
Satisfactory
Unsatisfactory
Unsatisfactory
Hydrogen Peroxide
---
Limited
Satisfactory
Moderate
Moderate
Hydrogen Sulfide
---
Moderate
---
Limited
Unsatisfactory
Isopropyl Alcohol
Satisfactory
Moderate
---
Satisfactory
Satisfactory
Kerosene
Moderate
Unsatisfactory
Satisfactory
Satisfactory
Satisfactory
Lacquer Thinner
Unsatisfactory
Unsatisfactory
---
Satisfactory
Limited
Liquid Dish Soap (10%)
Satisfactory
---
Satisfactory
Satisfactory
Satisfactory
Lubricating Oils
---
Moderate
Satisfactory
Satisfactory
Satisfactory
Magnesium Chloride (10%)
Satisfactory
Moderate
Satisfactory
Unsatisfactory
Unsatisfactory
Magnesium Hydroxide (10%)
Satisfactory
Moderate
Moderate
Satisfactory
Satisfactory
Methyl Ethyl Ketone
---
Unsatisfactory
Satisfactory
Satisfactory
Satisfactory
Methylene Chloride
Unsatisfactory
Unsatisfactory
Unsatisfactory
Satisfactory
Satisfactory
Mineral Spirits
Moderate
Unsatisfactory
Satisfactory
Satisfactory
Satisfactory
Motor Oil (10 weight)
Satisfactory
Limited
---
Satisfactory
Satisfactory
Nitric Acid (10%)
Limited
Moderate
Moderate
Limited
Limited
Perchlorethylene
Unsatisfactory
Unsatisfactory
---
Satisfactory
Satisfactory
Phosphoric Acid (25%)
Satisfactory
Moderate
Unsatisfactory
---
---
Phosphoric Acid (50%)
Satisfactory
Moderate
Unsatisfactory
Unsatisfactory
Unsatisfactory
Potassium Carbonate (10%)
Satisfactory
Satisfactory
Limited
Moderate
Limited
Potassium Chloride (25%)
Satisfactory
Satisfactory
Satisfactory
Satisfactory
Satisfactory
Potassium Hydroxide (25%)
Unsatisfactory
Satisfactory
Limited
Satisfactory
Satisfactory
Potassium Nitrate (10%)
Satisfactory
Satisfactory
Satisfactory
Satisfactory
Satisfactory
Potassium Sulfate (10%)
Satisfactory
Satisfactory
Satisfactory
Satisfactory
Satisfactory
Soap (lgepal) 10%
Satisfactory
Satisfactory
Satisfactory
Satisfactory
Satisfactory
Sodium Bicarbonate (10%)
Satisfactory
Satisfactory
Satisfactory
Satisfactory
Limited
Sodium Bisulfate (10%)
Satisfactory
Satisfactory
---
Unsatisfactory
Unsatisfactory
Sodium Chloride (25%)
Satisfactory
Satisfactory
Satisfactory
Moderate
Unsatisfactory
Sodium Hydroxide
Unsatisfactory
Moderate
Unsatisfactory
Moderate
Moderate
Sodium Hypochlorite
Satisfactory
Satisfactory
Limited
Limited
Unsatisfactory
Sodium Nitrate (10%)
Satisfactory
---
Satisfactory
Moderate
Moderate
Sodium Phosphate (10%)
Satisfactory
Satisfactory
Limited
Moderate
Unsatisfactory
Sulfuric Acid (25%)
Satisfactory
Satisfactory
Unsatisfactory
Unsatisfactory
Unsatisfactory
Tannic Acid (10%)
Satisfactory
Satisfactory
---
Moderate
Limited
Toluene
Unsatisfactory
Unsatisfactory
---
Satisfactory
Satisfactory
Trichloroethylene
---
Unsatisfactory
Unsatisfactory
Moderate
Moderate
Trisodium Phosphate
---
Moderate
---
Moderate
---
Turpentine
Satisfactory
Unsatisfactory
Satisfactory
Satisfactory
Satisfactory
Vegetable Oils
---
Satisfactory
Satisfactory
Satisfactory
Satisfactory
Xylene
Unsatisfactory
Unsatisfactory
Satisfactory
Moderate
Moderate
Zinc Chloride
Moderate
Satisfactory
---
Moderate
Unsatisfactory

*This is a general guide. The specific environment should be taken into consideration when selecting an enclosure.

Properties & Resistance of Gasket Material

Gaskets play an essential role in enclosure protection. In the long run, the IP rating and its reliability depend mainly on the properties of the gasket used in the enclosure. Key performance factors of a gasket are its compression set and proper fit in the gasket groove. The best general purpose gasket material is polyurethane which has an exceptionally low compression set. When accurately foam injected, the polyurethane gaskets stay tightly in the right place. EPDM material provides the best protection against the most popular industrial chemicals. However, it is wise to check the effect of a chemical on each gasket material since the chemical resistance of gasket materials varies greatly.

In some cases the performance of an enclosure can be modified by changing its gasket. The degree of protection depends on the material and the cross-section profile of the gasket. In addition to the cross-section profile of the gasket, there is the cross section of the gasket's contact with the surfaces of the enclosure's bases and covers. If the cross-section structures and manufacturing accuracy of an enclosure are not top quality, the IP rating will remain low even when equipped with a good gasket. When choosing gasket material, compare the elasticity properties of different materials and how these properties are affected by cold and heat, or by contact with various chemicals. An important factor is that both the enclosure and gasket must withstand the same chemicals in order to reach a safe resistivity.

PUR Gaskets (Polyurethane)

PUR differs from other gasket materials as it is shaped by special foam injection in the enclosure's gasket groove (usually in the cover). In this way, the gasket sticks permanently and securely to the enclosure. This ensures a reliable IP rating. PUR gaskets have an extremely low permanent compression set (the amount of residual displacement after the compressing load has been removed). In addition, the mechanical properties remain stable in -50 to + 130 ºC temperature range. The material can easily withstand various weather conditions. PUR gaskets are resistant to fats, oils, and acids, but they do not withstand strong alkalis.

EPDM Gaskets (Ethylene-Prophenediene-Monomer)

These gaskets have a very low permanent compression set and are resistant to cold and heat in a wide -50 to +120 ºC temperature range. Ozone, oxygen and UV radiation have little effect on EPDM gaskets which makes them suitable for outdoor conditions. Due to their chemical structures, EPDM gaskets resist polar solvents well. The gasket material is suitable for application environments where tolerance is required against water, salt fluids, steam, alcohols, glycols, phosphate based esters or weak acids, and weak alkalis. EPDM gaskets are not resistant to many oils and hydrocarbon based solvents.

NEOPRENE Gaskets (Chloroprene Rubber)

These gaskets have a very low permanent compression set and are resistant to cold and heat in a wide -50 to +120 ? temperature range. Ozone, oxygen and UV radiation have little effect on EPDM gaskets which makes them suitable for outdoor conditions. Due to their chemical structures, EPDM gaskets resist polar solvents well. The gasket material is suitable for application environments where tolerance is required against water, salt fluids, steam, alcohols, glycols, phosphate based esters or weak acids, and weak alkalis. EPDM gaskets are not resistant to many oils and hydrocarbon based solvents.

Silicone Gaskets

Silicone gaskets have an exceptionally wide -60 to + 170 ºC temperature resistance range. They are primarily used in extremely cold or hot environments. Silicone is resistant to alcohols and ketones, but strong acids and strong alkalis have dissolving effects on the material.

Properties
Temperaturee Range (ºC)
Tensile (Mpa)
Elongation at Break (%)
Hardness (Shore A)
Density (g/cm3)
Compression Set (%)
PUR
-50 to +130
0.4
110
12
0.33
5
EPDM
-50 to +120
13.0
300
65
1.12
20
Neoprene
-40 to +100
8.0
250
66
1.6
35
Silicon
-60 to +170
9.4
540
52
1.15
14

*Physical Property Table includes some commonly-used physical properties of the gaskets.

Chemicals
Neutral salts
Acids low concentrate
Acids high concentrate
Alkalis low concentrate
Alkalis high concentrate
Petroleums
Hydraulic oils
Alcohols
Cooling fluids
PUR
ERDM
Neoprene
Silicon

*Chemical Performance Table contains only rough generalizations to give you some clues to gasket material behavior. The resistance of each chemical should be checked separately.

Flammability & Fire Safety UL 94 Classification

UL 94 is the standard applied by the American Underwriters Laboratories for the testing of the flammability and fire safety of plastic materials used in devices and appliances. The UL 94 HB (Horizontal Burning) tests the burning of a horizontal plastic specimen and the most demanding UL 94V (Vertical Burning) tests the burning of a vertical plastic specimen. Precise details of the equipment, conditions and test systems to be used can be found in the UL 94 standard.

UL 94 HB: Horizontal Burning Test

The length of the test specimen is 5" (127 mm) and width 0.5" (12.7 mm). The test sheet cannot be more than 0.5 (12.7 mm) thick. Lines are marked on the sheet at the 1" and 4" locations. The sheet is fixed horizontally at one end and tilted 45 degrees in the direction of the width, as shown in the diagram. The burner used is adjusted so that it forms a 1" long blue flame. The flame is directed at an angle of 45 degrees to the front edge of the plastic sheet so that about 1/4 of the test specimen’s front edge is in the flame. The flame is applied for 30 seconds, after which it is removed. If the test specimen burns to the 1" line before 30 seconds have passed the flame is removed immediately. The test is carried out on three test sheets.

The material under investigation is classified as UL 94 HB if, after the removal of the flame either condition below is true:

  • The speed of burning does not exceed 1.5" (38.1 mm) per minute when the test specimen thickness is .120-.500" (3.05-12.7 mm)
  • The speed of burning does not exceed 3.0" (76.2 mm) per minute when the thickness of the specimen is less than .120" (3.05 mm)
  • Burning finishes before the flame reaches the 4" line

UL 94 V-0, V-1 and V-2 Vertical Burning Test

The test specimen length is 5" (127 mm) and width 0.5" (12.7 mm). The sheet to be tested can not be more than 0.5" (12.7mm) thick. The sheet is fixed 1/4" from the upper end in the vertical position. A metal mesh covered with surgical cotton is positioned 12" (305 mm) beneath the test sheet. The flame of the burner used is adjusted so that is forms a 3/4" blue flame. The flame is directed from below at the lower edge of the plastic sheet at a distance of 3/8" (9.5 mm). The flame is applied for 10 seconds, after which it is removed. The burning time of the test specimen is recorded. Immediately the burning stops the flame is reapplied for 10 seconds. After removal of the flame the burning time and afterglow time is again noted. The entire test is carried out on five different test specimens.

The material tested is UL 94 V-O classified if:

  • None of the five test specimen burn for over 10 seconds at any time when the burner flame is removed.
  • The total burning time of the 10 ignition test does not exceed 50 seconds.
  • No test specimen burns either with a flame or afterglow to the clamp.
  • No burning drops should fall which would cause the cotton underneath to ignite from any test specimen.
  • The afterglow burning of no test specimen exceeds 30 seconds.

The material tested is UL 94 V-1 classified if:

  • None of the five test specimen burn for over 30 seconds at any time when the burner flame is removed.
  • The total burning time of the 10 ignition test does not exceed 250 seconds.
  • No test specimen burns either with a flame or afterglow to the clamp.
  • No burning drops should fall which would cause the cotton underneath to ignite from any test specimen.
  • The afterglow burning of no test specimen exceeds 60 seconds.

The material tested is UL 94 V-2 classified if:

  • None of the five test specimen burn for over 30 seconds at any time when the burner flame is removed.
  • The total burning time of the 10 ignition test does not exceed 250 seconds.
  • No test specimen burns either with a flame or afterglow to the clamp.
  • Only such burning pieces may fall from the test specimen, which burn only momentarily, and of which some ignite the cotton underneath.
  • The afterglow burning of no test specimen exceeds 60 seconds.

UL 94 5V Vertical Burning Test

The length of the test specimen is 5" (127 mm) and the width 0.5 (12.7 mm). The test sheet shall not be more than 0.5" (12.7 mm) thick. Flammability classification is granted for specific thickness intervals, for which both the maximum thickness and minimum thickness sheet must be tested. The test sheet is fixed 1/4" from the upper end in the vertical position. The flame of the burner used is adjusted so that it forms a 5" flame whose blue heart is 1,57" (40mm) long. The flame is directed from below at the corner of the plastic sheet at a distance of 1". The flame is applied for 5 seconds, after which it is removed for 5 seconds. This is repeated five times. The entire test is carried out on five test specimen.

The material tested is VI 94-5V classified if:

  • No test specimen burns with a flame or afterglow for more than 60 seconds after the fifth ignition.
  • The total burning time of the 10 ignition test does not exceed 250 seconds.
  • No material drops from the test specimen.

Electrical Enclosure NEMA Ratings

The National Electrical Manufacturers Association (NEMA) is a U.S. Manufacturers Organization that actively promotes standardized product specifications for electrical apparatus. NEMA performance criteria and test methods are used by Underwriters' Laboratories as guidelines for investigation and listing of electrical enclosures.

NEMA
Description
1
Indoor use primarily to provide a degree of protection against contact with the enclosed equipment and against a limited amount of falling dirt. (IP30)
2
Indoor use to provide a degree of protection against limited amounts of falling water and dirt. (IP31)
3
Outdoor use to provide a degree of protection against windblown dust, rain, and sleet; undamaged by the formation of ice on the enclosure. (IP64)
3R
Outdoor use to provide a degree of protection against falling rain and sleet: undamaged by the formation of ice on the enclosure. (IP32)
3S
Outdoor use to provide a degree of protection against windblown dust, rain and sleet; external mechanisms remain operable while ice laden.
4
Indoor or outdoor use to provide a degree of protection against splashing water, windblown dust and rain, hose directed water; undamaged by the formation of ice on the enclosure. (IP66)
4X
Indoor or outdoor use to provide a degree of protection against splashing water, windblown dust and rain, hose directed water; undamaged by the formation of ice on the enclosure, resists corrosion. (IP66)
6
Indoor or outdoor use to provide a degree of protection against the entry of water during temporary submersion at a limited depth; undamaged by the formation of ice on the enclosure.
6P
Indoor and outdoor use to provide a degree of protection against the entry of water during prolonged submersion at a limited depth.
11
Indoor use to provide by oil immersion a degree of protection of the enclosed equipment against the corrosive effects of corrosive liquids and gases.
12, 12K
Indoor use to provide a degree of protection against dust, falling dirt and dripping noncorrosive liquids. (IP65)
13
Indoor use to provide a degree of protection against dust and spraying of water, oil and noncorrosive coolants. (IP65)

*Approximate IP equivalents in parentheses.

Electrical Enclosure IP Ratings

Ingress protection class of enclosures is given in form of IP classification, a two digit coding which is shown below. The latter requires the second digit to be tested from class 6 upwards separately to each level of class, thus the double marking IP 66 / IP 67 indicates that the actual tests have been made for both levels.

Solid Objects { First Digit }
Moisture { Second Digit }
0
Protected against solid objects larger than 50 mm
0
Protected against solid objects larger than 12 mm
1
Protected against solid objects larger than 50 mm
1
Protected against solid objects larger than 12 mm
2
Protected against solid objects larger than 50 mm
2
Protected against solid objects larger than 12 mm
3
Protected against solid objects larger than 50 mm
3
Protected against solid objects larger than 12 mm
4
Protected against solid objects larger than 50 mm
4
Protected against solid objects larger than 12 mm
5
Protected against solid objects larger than 50 mm
5
Protected against solid objects larger than 12 mm
6
Lorem
6
Protected against solid objects larger than 12 mm
IP
6
1st Digit
5
2nd Digit
7
Protected against solid objects larger than 12 mm
8
Protected against solid objects larger than 12 mm
Ingress protection Chart