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How to Design Cable Entries for Waterproof Electrical Enclosures

Cable-entry design is an important part of a waterproof

Technician inspecting cable gland holes in a customized waterproof electrical enclosure
Technician inspecting cable gland holes in a customized waterproof electrical enclosure
01
Article overview

Why Cable-Entry Design Matters

Cable-entry design is an important part of a waterproof electrical enclosure.
Incorrect hole sizes, unsuitable cable glands or poor entry positions can reduce
sealing performance and make installation difficult.

Before ordering a customized enclosure, buyers should confirm the cable diameter,
gland size, entry direction, internal components and required hole positions.
This guide explains the main points to check before CNC machining.

Every opening added to an enclosure may become a possible path for water or dust.
The enclosure, cable glands, sealing plugs and installation method must work together
as one complete system.

Common problems include:

  • Holes that are too large or too small
  • Cable glands that do not match the cable diameter
  • Entries positioned too close to the enclosure edge
  • Insufficient space between adjacent cable glands
  • Unused holes without sealing plugs
  • Cables blocking internal components

Buyers can review BOWO Electric's

waterproof electrical enclosure range

before selecting a suitable box for customization.

02
Section 02

Confirm the Cable Diameter First

Cable glands are selected according to the outside diameter of the complete cable,
not only the conductor size.

For each cable, provide:

  • Cable outside diameter
  • Cable quantity
  • Cable function
  • Required gland size
  • Preferred entry direction

The cable diameter must remain within the gland's specified clamping range.
A gland that is too large may not seal correctly, while a gland that is too small
may damage the cable or make installation impossible.

03
Section 03

Choose the Correct Entry Position

Bottom Entry

Bottom cable entries are commonly used for outdoor wall-mounted enclosures because
they reduce direct exposure to falling rain.

In BOWO Electric's

roadside CCTV junction box project

power and communication cables entered through sealed bottom cable glands.

Side Entry

Side entries are suitable when cables run horizontally between machines or cabinets.
Enough space should be left for tightening tools and cable bends.

Top Entry

Top entries may be required when cables descend from an overhead tray. However,
they need careful sealing because they may be directly exposed to rainwater.

04
Section 04

Leave Enough Space Between Cable Glands

Cable glands should not be installed too close together. Installers need space for
locknuts, sealing washers, tools and cable bending.

The spacing should be based on the external gland size and internal locknut size,
not only the hole diameter.

05
Section 05

Check the Internal Components

Before machining, confirm that each cable entry will not interfere with:

  • DIN rails
  • Terminal blocks
  • Circuit breakers
  • Mounting plates
  • Cover screws
  • Hinges and latches
  • The cover gasket

For organized cable connections, a

waterproof terminal block junction box

can provide a clear internal wiring structure.

06
Section 06

Allow Enough Cable Bending Space

Large power cables require more internal space than signal cables. The enclosure
should provide enough room for cable bending, terminal connection and future
maintenance.

When frequent inspection is required, an

IP66 hinged waterproof junction box

may provide easier access than a removable screw-fixed cover.

07
Section 07

Seal All Unused Openings

Spare cable-entry holes must be closed with suitable sealing plugs. Temporary caps,
tape or open holes should not be used as permanent outdoor sealing solutions.

BOWO Electric's

barrier gate junction box case

also shows the importance of proper cable entry and enclosure sealing.

08
Section 08

CNC Machining or Manual Drilling?

Manual drilling may be acceptable for a small one-time installation, but CNC machining
provides better consistency for repeated production and OEM projects.

Comparison Manual Drilling CNC Machining
Hole position May vary Based on approved drawing
Repeated orders Lower consistency More consistent production
Complex cutouts Difficult Suitable for multiple openings
Installation time Requires site work Ready for assembly

Learn more about CNC openings, printing, colors and custom structures in BOWO
Electric's guide to

waterproof junction box customization
.

09
Section 09

Prepare a Clear Machining Drawing

The drawing should clearly show:

  • Enclosure model and dimensions
  • Hole diameter
  • Hole quantity
  • Distance from enclosure edges
  • Entry surface
  • Cable gland or connector model
  • Drawing revision number

A drawing is more reliable than a photograph with approximate markings.
The approved drawing should be used for sample production and mass production.

10
Section 10

Approve a Sample Before Mass Production

A sample is recommended when the enclosure includes customized holes, connectors,
cable glands or internal components.

The sample should be checked for:

  • Hole size and position
  • Cable gland installation
  • Internal locknut clearance
  • Cable bending space
  • Cover closing
  • Gasket condition
  • Internal component fit
11
Section 11

Does Machining Affect the IP Rating?

The protection of the completed enclosure depends on the enclosure body, machining,
cable glands, sealing plugs and final installation.

Buyers should confirm which documentation applies to the selected model and
configuration through BOWO Electric's

qualification page

12
Section 12

Common Design Mistakes

  • Providing conductor size instead of cable outside diameter
  • Drilling holes before selecting the gland
  • Placing holes too close to the edge
  • Ignoring the internal locknut size
  • Leaving insufficient cable bending space
  • Leaving unused openings unsealed
13
Section 13

Which Enclosure Type Should You Choose?

Application Recommended Enclosure Type
Simple cable connection Waterproof junction box
Multiple terminal connections Terminal block junction box
DIN-rail circuit breakers Waterproof distribution box
Frequent maintenance Hinged enclosure
Custom connectors or controls CNC-machined OEM enclosure

Compact outdoor cable connections can consider an

IP67 outdoor waterproof junction box

Projects containing DIN-rail breakers can review the

IP65 waterproof electrical distribution box

14
Section 14

Information Needed for a Quotation

Send the following information with your inquiry:

  1. Enclosure size or preferred model
  2. Cable outside diameters
  3. Cable gland specifications
  4. Hole positions and dimensions
  5. Internal component layout
  6. Required material and color
  7. Installation environment
  8. Required quantity
  9. Delivery destination
15
Section 15

Need Custom Cable Entries for Your Enclosure?

Send BOWO Electric your cable information, gland drawings and enclosure layout.
The team can review a suitable standard model and evaluate CNC machining options.


Send Your Cable Entry Drawing

16
Section 16

Frequently Asked Questions

What cable size information should I provide?

Provide the outside diameter of the complete cable, together with the required cable
gland or connector specification.

Can cable-gland holes be machined before delivery?

Yes. Standard enclosures can be evaluated for CNC-machined gland holes, connector
openings and other customized cutouts.

Should outdoor cables enter from the bottom?

Bottom entry is commonly used for outdoor wall-mounted boxes, but the final direction
should depend on rainfall, cable routing and installation height.

Should a sample be approved first?


Yes. Sample approval is recommended when the project includes customized holes,

large cables, connectors or repeated OEM production.

Planning a project?

Share the application, installation environment and enclosure requirements with our engineering team.

Request a Quote Talk to Engineering