Choosing an electrical enclosure involves much more than finding a box large enough to hold the equipment. Material, ingress protection, cable entry, corrosion, mechanical impact, internal heat and installation location can all influence whether the enclosure performs reliably.
This guide compares steel enclosures, non-metallic or PVC electrical enclosures, and weatherproof enclosure options, while explaining what to consider when specifying industrial electrical wiring enclosures.
Quick Answer
Choose the enclosure according to the environment and equipment inside it. Steel offers robust construction and extensive custom fabrication options. Suitable plastic enclosures offer corrosion resistance, low weight and electrical insulation. For outdoor or wet environments, select a complete enclosure system with an appropriate ingress-protection rating rather than relying on material alone.
In This Guide
01 / The Basics
What Is an Electrical Enclosure?
An electrical enclosure is a housing designed to contain and protect electrical or electronic components.
Depending on the installation, the enclosure may contain terminals, circuit breakers, contactors, PLC equipment, power supplies, drives, relays, busbars or other control and distribution components.
A correctly selected enclosure helps:
02 / Metal Enclosures
When Should You Choose Steel Enclosures?
Steel enclosures are widely used in industrial electrical applications because they can provide robust mechanical protection and can be manufactured in a wide range of sizes and configurations.
Sheet steel can be cut, punched, bent, welded and finished around the equipment layout rather than forcing the equipment into a standard box.
Mechanical Strength
Steel is commonly selected where the enclosure may be exposed to demanding industrial handling or mechanical conditions.
Custom Fabrication
Doors, mounting plates, gland plates, brackets and equipment cut-outs can be manufactured around the project requirement.
Large Sizes
Steel construction works well for larger wall-mounted and floor-standing cabinets containing substantial electrical assemblies.
Finishing Options
Suitable coatings can be applied according to the environment and required appearance.
03 / Custom Manufacturing
What Are Sheet Metal Enclosures?
Sheet metal enclosures are manufactured by cutting and forming relatively thin metal sheets into the required cabinet, box or panel shape.
A typical manufacturing workflow can include:
Drawing
Cutting
Punching
Bending
Welding
Finishing
Assembly
This allows the enclosure dimensions, doors, access panels and cable entries to follow the electrical design instead of being limited to standard stock sizes.
04 / Non-Metallic Enclosures
When Should You Choose PVC or Plastic Electrical Enclosures?
Searches for PVC electrical enclosures often refer broadly to non-metallic electrical boxes and cabinets. In practice, enclosure manufacturers may use several engineered plastic materials, including thermoplastics and reinforced plastics.
Suitable non-metallic enclosures can offer several advantages:
Corrosion Resistance
Plastic does not rust like ordinary carbon steel, making suitable products useful in wet or chemically aggressive environments.
Lower Weight
Non-metallic enclosures can be considerably lighter and easier to handle than comparable steel boxes.
Electrical Insulation
Plastic materials are naturally non-conductive, although the complete installation still needs to follow the applicable electrical design requirements.
Compact Applications
Plastic boxes are frequently practical for smaller junction, terminal and field-device installations.
Not Every Plastic Enclosure Is Suitable Outdoors
Outdoor suitability depends on the actual enclosure material and design. UV resistance, temperature range, sealing, mechanical strength and the manufacturer’s tested protection rating should be confirmed before installing a plastic enclosure outdoors.
05 / Environmental Protection
What Makes an Electrical Enclosure Weatherproof?
When buyers search for weatherproof enclosures electrical, the important question is not simply whether the box is steel or plastic.
Outdoor protection depends on the complete enclosure system, including:
- Door and cover seals.
- Ingress-protection rating.
- Material corrosion resistance.
- Outdoor and UV suitability.
- Cable glands and cable-entry sealing.
- Door hardware and locking design.
- Drainage or condensation strategy where required.
- Canopies, shields or other project-specific protection.
06 / Ingress Protection
Understanding IP Ratings for Electrical Enclosures
IP stands for Ingress Protection. The rating describes a defined level of protection provided by the enclosure against access and ingress of solid objects and water.
FIRST DIGIT
Solid Objects
Indicates the specified level of protection relating to access and solid foreign objects.
SECOND DIGIT
Water
Indicates the specified level of protection against water ingress under defined test conditions.
A higher IP number should not automatically be specified simply because it sounds better. The rating should match the real installation environment and the complete enclosure configuration.
07 / Material Comparison
Steel vs PVC / Plastic Electrical Enclosures
| Consideration | Steel Enclosure | PVC / Plastic Enclosure |
|---|---|---|
| Mechanical Robustness | Well suited to demanding industrial fabrication | Depends strongly on material and product design |
| Corrosion | Requires appropriate material or protective finish | Does not rust like carbon steel |
| Weight | Heavier | Generally lighter |
| Electrical Conductivity | Conductive material | Non-conductive material |
| Custom Large Sizes | Highly suited to custom sheet-metal fabrication | Often product-range dependent |
| Outdoor Use | Possible with suitable design, material and finish | Possible when product is UV/weather rated |
| Custom Cut-Outs | Excellent fabrication flexibility | Possible, but dependent on enclosure construction |
08 / Outdoor Installation
Choosing an Electrical Enclosure for Outdoor Use
An outdoor enclosure may face several environmental conditions at the same time.
An enclosure described as weatherproof should therefore be evaluated against the actual conditions at the installation location, not simply the fact that it has a sealed door.
Mild Steel vs Stainless Steel for Electrical Enclosures
The term “steel enclosure” also covers different material choices.
Mild steel is commonly used for industrial enclosures and can be protected using an appropriate coating system. Stainless steel may be considered where greater corrosion resistance is required.
The correct option depends on the environment, project specification, fabrication requirement and lifecycle expectations.
09 / Wiring & Installation
Cable Entry Matters in Electrical Wiring Enclosures
An enclosure can be perfectly manufactured and still cause installation problems if cable entry has not been planned properly.
For electrical wiring enclosures, consider:
- Top, bottom or side cable entry.
- Cable quantity and diameter.
- Gland sizes.
- Fixed or removable gland plates.
- Minimum cable bend radius.
- Separation between circuits where required.
- Internal wiring duct positions.
- Maintaining the required enclosure protection after cable entry.
Do Not Select an Enclosure Using Outside Dimensions Alone
The internal layout is equally important.
Allow space for:
What About Heat Inside a Weatherproof Enclosure?
Electrical and electronic equipment can generate heat during operation. A tightly sealed enclosure can limit natural air exchange with the surrounding environment.
Designers should therefore consider internal heat load, ambient temperature, solar exposure and any required ventilation, heat exchange or cooling system. Environmental sealing and thermal management should be considered together rather than independently.
Common Applications
Where Are Electrical Enclosures Used?
Control Panels
Housing automation, PLC and control equipment.
Distribution Boards
Electrical distribution and protective devices.
Junction Boxes
Protecting terminals, joints and field wiring.
Machine Controls
Localised equipment control and interface hardware.
Outdoor Equipment
Field-mounted electrical and automation installations.
Industrial Utilities
Electrical equipment used throughout plant and infrastructure environments.
10 / Selection Checklist
How to Choose the Right Electrical Enclosure
Before selecting or ordering an enclosure, define the complete requirement.
Indoor, sheltered, outdoor or harsh industrial area?
Mild steel, stainless steel or non-metallic?
What dust and water exposure exists?
Will all equipment, ducts and wiring fit comfortably?
Where will cables enter and how will they be sealed?
Wall, floor, pole, machine or custom bracket?
How much heat will the internal equipment generate?
What corrosion protection or colour is required?
What Should You Send When Requesting an Enclosure Quote?
- Enclosure dimensions or drawings.
- Material requirement.
- Required protection rating.
- Wall-mounted or floor-standing arrangement.
- Equipment layout where available.
- Door and access requirements.
- Cable-entry direction.
- Gland plate requirements.
- Cut-outs and mounting provisions.
- Required finish.
- Quantity.
- Delivery location and required date.
Custom Electrical Enclosures
When a Standard Box Does Not Fit the Project
Off-the-shelf enclosures are useful when the dimensions, access and cable entry already suit the installation. Custom fabrication becomes valuable when the enclosure needs to fit around a specific electrical layout or site constraint.
Stärk Stahl manufactures custom steel electrical enclosures and related electrical products around project drawings and specifications.
For projects requiring a defined ingress-protection level, the rating and complete enclosure configuration should form part of the approved specification before manufacturing begins.
Frequently Asked Questions
Electrical Enclosure FAQs
Is steel or PVC better for electrical enclosures?
Neither material is universally better. Steel is useful where robust construction and custom fabrication are priorities, while suitable plastic materials can offer corrosion resistance, low weight and electrical insulation.
Are PVC electrical enclosures waterproof?
The material alone does not make an enclosure waterproof. Water protection depends on the complete enclosure design, seals, cable entries and tested ingress-protection rating.
What makes an electrical enclosure weatherproof?
Weather resistance depends on sealing, ingress protection, material suitability, outdoor and UV resistance, cable-entry design and other installation details.
What does an IP rating mean?
The IP Code describes specified degrees of protection provided by an enclosure. Its digits relate to protection involving solid objects and water.
Can steel electrical enclosures be used outdoors?
Yes, provided the enclosure material, protective finish, sealing, ingress rating and overall design are appropriate for the outdoor environment.
When should stainless steel be used for an enclosure?
Stainless steel may be considered where the installation requires increased corrosion resistance or where the project specification calls for it.
Can sheet metal enclosures be custom made?
Yes. Sheet metal fabrication allows enclosure size, doors, gland plates, cut-outs and mounting features to be produced around project-specific requirements.
Why are gland plates important?
Gland plates provide organised cable-entry areas and can make installation, sealing and future maintenance easier when properly designed.
What should I provide for a custom electrical enclosure quote?
Provide drawings or dimensions, material, required protection level, cable-entry requirements, cut-outs, mounting arrangement, quantity, finish and delivery date.
Built Around the Installation
Need a Custom Steel Electrical Enclosure?
Send your enclosure drawings, dimensions, equipment layout, environmental requirements and cable-entry details to Stärk Stahl to discuss a custom enclosure built around your installation.
Request an Enclosure Quote