Waterproof electrical enclosures for solar PV and battery energy storage systems

Where Are Waterproof Enclosures Used in Solar and Energy Storage Systems?

Solar photovoltaic and battery energy storage systems contain numerous electrical

connection points that may be installed outdoors, beside equipment cabinets or

across distributed project locations. These connections can be exposed to rain,

dust, humidity, ultraviolet radiation, temperature changes and maintenance activity.

A correctly selected waterproof electrical enclosure helps protect terminals,

circuit breakers, communication modules, monitoring devices and cable connections.

However, enclosure selection should not be based only on external dimensions or a

published IP rating. Project buyers must also consider the material, internal layout,

cable-entry design, installation orientation and long-term maintenance requirements.

This guide explains how EPC contractors, solar equipment manufacturers, energy

storage integrators, electrical distributors and project procurement teams can

evaluate waterproof enclosures before requesting a quotation.

Waterproof electrical boxes may be used at several positions within a photovoltaic

or battery energy storage project. The required enclosure structure will depend on

the electrical components, installation environment and service requirements at each

position.

  • PV string and branch cable connection points
  • DC protection and isolation equipment
  • DIN-rail circuit breaker installations
  • Monitoring and communication modules
  • Weather-station and sensor connections
  • Battery cabinet auxiliary control circuits
  • Outdoor inverter communication wiring
  • Lighting, security and maintenance power circuits

Buyers can review BOWO Electric's


waterproof electrical enclosure product range


to compare junction boxes, distribution boxes, terminal boxes and control enclosures

for different system positions.

Start with the Actual Installation Position

The term “outdoor installation” is not sufficiently detailed for accurate product

selection. A box mounted beneath a solar canopy experiences different exposure from

an enclosure installed on an open tracker structure or close to ground level.

Before selecting a model, confirm the following site conditions:

  • Whether the enclosure is completely exposed or installed under a shelter
  • Expected rain direction and water exposure
  • Direct sunlight and daily ultraviolet exposure
  • Maximum and minimum ambient temperatures
  • Dust, sand, salt, oil or chemical exposure
  • Possibility of standing water or temporary flooding
  • Installation height and mounting orientation
  • How frequently technicians must open the enclosure

Installation Position | Main Risks | Selection Priorities

Under a solar canopy | Humidity, dust and occasional splash | Sealed cover, controlled cable entry and adequate internal space

Open ground-mounted PV array | Sunlight, rain, dust and temperature variation | Suitable material, secure mounting and outdoor sealing

Battery storage equipment area | Heat, multiple circuits and repeated inspection | Internal separation, maintenance access and component clearance

Low-level cable connection point | Splash, cleaning water and accumulated moisture | Appropriate IP protection, sealed glands and installation height

Monitoring or communication point | Condensation, small cables and signal interruptions | Controlled cable routing, terminal space and reliable sealing

How Should IP65, IP66 and IP67 Be Compared?

The IP rating describes an enclosure's protection against solid particles and water

under defined test conditions. It is an important selection reference, but it does

not guarantee the performance of every completed installation.

Drilled openings, cable glands, unused cable-entry holes, mounting screws and cover

installation can all affect the protection of the final assembly. Buyers should

therefore confirm the applicable rating for the exact model and configuration being

ordered.

IP65 Enclosures

IP65 enclosures may be considered for installations requiring protection against dust

and water jets, subject to the applicable product specification and installation

conditions.

For systems containing modular circuit breakers or other DIN-rail components, an


IP65 waterproof electrical distribution box


with a transparent cover can support visual inspection without opening the main

enclosure door.

IP66 Enclosures

IP66 models are generally evaluated for more exposed locations or installations

subject to stronger water jets. They may be used around outdoor equipment, distributed

electrical connections and renewable-energy systems when the selected model and

installation meet the project requirements.

When technicians require repeated access, an


IP66 hinged waterproof junction box with metal latches


can provide easier access than a cover secured by multiple individual screws.

IP67 Enclosures

IP67 describes dust protection and resistance to temporary immersion under specified

test conditions. It should not automatically be interpreted as approval for continuous

underwater use.

Distributed cable and terminal connections can consider an


IP67 outdoor waterproof junction box


when the model, cable glands, entry positions and site conditions are suitable.

Important: The enclosure IP rating does not replace the electrical

system design, component protection or installation requirements defined by the

project engineer and applicable local standards.

Select the Enclosure Around the Internal Components

Choosing an enclosure only by its external dimensions is a common procurement mistake.

Internal screw columns, mounting ribs, hinges, gaskets and cover structures reduce the

usable installation space.

The internal layout should allow sufficient room for:

  • DIN rails and modular protection devices
  • DC breakers, isolators or fuse holders
  • Terminal blocks and grounding terminals
  • Monitoring or communication modules
  • Cable bending radius
  • Safe separation between applicable circuits
  • Installation tools and maintenance access
  • Heat dissipation and component clearance
  • Future wiring or component expansion

For selected DC distribution applications, the


HTC Series IP65 side-open DC distribution box


includes a transparent inspection area, internal guide rail and side cable-entry

arrangement. The final suitability must still be confirmed according to the installed

components and project conditions.

Plan Cable Entries Before Ordering

Cable-entry design is one of the most important parts of a waterproof electrical

enclosure. A well-manufactured enclosure can lose its environmental protection when

entry holes are incorrectly sized, positioned too close together or fitted with

unsuitable glands.

A complete cable-entry drawing should identify:

  • The number of incoming and outgoing cables
  • The outside diameter of every cable
  • The required gland or connector thread
  • The entry surface and installation direction
  • The center position of each opening
  • The distance between adjacent openings
  • Unused openings that require sealing plugs
  • Required strain relief or conduit connections

Bottom-facing cable entries are commonly considered for exposed outdoor installations

because they reduce direct exposure to falling rain. However, the correct position

depends on the cable route, mounting surface and equipment layout.

Buyers should send a dimensioned drawing whenever CNC machining is required. For an

overview of machining, logo, color and structural options, see the guide to


customizing waterproof junction boxes for OEM projects

.

Choose Materials According to the Environment

Material selection affects impact resistance, dimensional stability, appearance,

outdoor durability and production cost. ABS and polycarbonate are common materials

for plastic electrical enclosures, but they should not be treated as interchangeable

in every environment.

ABS Enclosures

ABS can provide a practical balance of mechanical performance, electrical insulation

and manufacturing efficiency for many general industrial and selected outdoor

applications. Long-term sunlight, chemical exposure and temperature requirements

should be confirmed for the specific material grade.

Polycarbonate Covers and Components

Transparent polycarbonate covers are useful when circuit breakers, indicators or

internal equipment need to be checked without opening the enclosure. Material

suitability for ultraviolet exposure and impact requirements should be confirmed

for the selected product.

Some projects use an ABS body with a transparent PC cover. This configuration can

combine an opaque enclosure base with convenient internal visibility, but it does

not remove the need to verify the complete product specification.

Consider Heat, Condensation and Pressure Changes

Solar and energy storage equipment may experience significant differences between

daytime and nighttime temperatures. Heat generated by internal electrical components

can also raise the temperature inside the enclosure.

During enclosure evaluation, project engineers should consider:

  • Heat generated by the installed components
  • Expected internal and external temperature range
  • Required clearance around heat-producing devices
  • Possibility of condensation during temperature changes
  • Whether approved ventilation or pressure-equalization components are required
  • Whether ventilation changes the required ingress protection

Ventilation holes should not be added without evaluating their effect on the enclosure

protection. Any membrane vent, filter or pressure-equalization device must be selected

as part of the complete enclosure system.

Match the Cover Design to Maintenance Frequency

The best cover structure depends on how frequently the enclosure must be opened.

Screw-Fixed Covers

Screw-fixed covers are suitable for connection points that are rarely opened.

Tightening the cover screws evenly helps maintain consistent gasket compression.

Hinged Covers

Hinged covers are useful for equipment requiring periodic inspection or wiring

changes. The cover remains attached to the body, reducing the risk of a separate

lid being dropped or misplaced during maintenance.

Transparent Covers

Transparent covers allow technicians to inspect breaker positions, indicators and

visible internal conditions without opening the enclosure unnecessarily. They are

especially useful for distributed installations where routine inspection time is

important.

What Documentation Should a Project Buyer Request?

Procurement teams should not assume that every certificate shown by a manufacturer

applies to every enclosure model. Documentation is normally model-specific and may

depend on the material, size and product configuration.

Before approving an order, request the applicable:

  • Product specification and dimensional drawing
  • Material information
  • IP or IK test information where applicable
  • CE or RoHS documentation where applicable
  • Installation instructions
  • Cable-entry machining drawing
  • Sample approval record
  • Packaging specification

Available company and product documents can be reviewed through BOWO Electric's


qualification and certification page

.

Buyers should confirm which document applies to the exact model included in the

quotation.

Manufacturer Experience from Photovoltaic and Energy Storage Discussions

During BOWO Electric's participation in


SNEC PV&ES Expo 2026

,

customer discussions repeatedly focused on enclosure size, cable-entry configuration,

DIN-rail installation, outdoor sealing and product customization.

These questions show why project inquiries should include more than a required IP

rating. A supplier needs to understand the complete assembly before recommending a

standard enclosure or evaluating an OEM modification.

BOWO Electric has manufactured waterproof electrical products since 2017. More

information about its manufacturing background and product capabilities is available

on the


BOWO Electric factory and company page

.

Standard Enclosure or Customized Enclosure?

A completely new injection mold is not required for every project. Standard enclosure

platforms can often be adapted through CNC machining, accessory installation, printing

or internal component preparation.

Project Requirement | Possible Approach

Standard size with several cable entries | Existing enclosure with CNC-machined holes

DIN-rail breakers and transparent inspection | Standard waterproof distribution box

Frequent maintenance access | Hinged enclosure with suitable latch configuration

Private-label product branding | Printing, laser marking or customized packaging

Unique component layout or high production volume | Custom structural design or new mold evaluation

Need an Enclosure Recommendation for Your Solar Project?

Send BOWO Electric your component layout, required dimensions, cable-entry drawing,

installation environment and estimated order quantity. The project information can

be reviewed to identify a suitable standard enclosure or evaluate customized

manufacturing options.


Send Your Solar Enclosure Requirements