Wiska COMBI 304 Installation Guide – Features, Sizes and IP Ratings
This Wiska COMBI 304 installation guide explains the features of Wiska’s compact circular junction box, including its dimensions, cable entries, mounting arrangement and IP protection. The COMBI 304 system also offers specialised LED and rotary-switch versions, making it an interesting option for selected domestic, commercial and outdoor electrical installations.
What Makes the Wiska COMBI 304 Different?
Unlike the rectangular and square designs found elsewhere in the COMBI family, the Wiska COMBI 304 uses a circular enclosure. Its compact profile can be useful for installations where the appearance and positioning of the junction box matter.
Wiska describes the COMBI 304 as suitable for architectural and retro-style installations. It is available in black, white and grey, allowing the enclosure colour to be selected according to the installation environment.
The box is manufactured from polypropylene with a TPE sealing gasket. The standard enclosure has a flat, quarter-turn bayonet lid and external mounting feet.
Wiska COMBI 304 Dimensions and Technical Features
The standard COMBI 304 enclosure is described in Wiska’s product data sheets as approximately 82 mm in diameter and 57 mm deep. Check the dimensions shown against the exact manufacturer SKU, particularly when working within restricted installation spaces.
- Compact circular enclosure design.
- Four M20 threaded membrane cable entries.
- IP66 protection when using the membrane entries correctly.
- IP67 protection with compatible ESKV glands installed according to Wiska’s instructions.
- Polypropylene construction with a TPE sealing gasket.
- Quarter-turn bayonet cover with a tool-operated opening mechanism.
- Two external mounting feet.
- White, black and grey colour options.
For the standard COMBI 304, Wiska specifies a cable diameter range of 3–12 mm for its membrane entries. Always check the cable and gland specifications for the particular installation.
Understanding the Four M20 Cable Entries
The Wiska COMBI 304 has four M20 threaded membrane entry positions. These provide flexibility when routing suitable cables into the enclosure.
The cable-entry arrangement should be planned before mounting the box. Consider how many cables are required, their external diameters, connector space and the direction from which cables will approach the enclosure.
Do not assume that all four entries must be opened or used. Unused entries should retain the appropriate protection, and any modified entries must follow the manufacturer’s instructions.
IP66 and IP67 Protection – What Is the Difference?
IP66 indicates dust-tight protection and resistance to powerful water jets under specified test conditions. IP67 provides protection against temporary immersion under defined testing conditions.
Wiska specifies IP66 protection for the COMBI 304 using its membrane entries. IP67 can be achieved using the threaded entries with suitable ESKV cable glands correctly installed.
The final protection depends on the entire installation, including the cable entry, gland, lid seal and enclosure condition. IP67 does not mean the standard COMBI 304 is intended for permanent immersion or direct burial.
How Is the COMBI 304 Mounted?
The standard COMBI 304 uses two external mounting feet. This arrangement allows the box to be fixed without relying on arbitrary drilling through the enclosure body.
Select suitable fixings for the mounting surface and consider the enclosure’s accessibility, cable routes and exposure to water. The box should be positioned to permit future inspection and maintenance where required.
The quarter-turn cover provides convenient access when the appropriate tool is used. Ensure the sealing surfaces are clean and the cover is correctly secured after installation.
Wiska COMBI 304 with WAGO Connectors
Selected COMBI 304 versions are supplied with WAGO lever connectors, while empty versions allow suitable connectors to be chosen separately.
Compact WAGO 221 connectors can be useful within a correctly sized enclosure, provided the conductor types, current ratings and available internal space meet the installation requirements.
When planning connections, allow sufficient space for cable bending, connector positioning and safe access. A small enclosure should not be overloaded simply because multiple cable entries are available.
Wiska COMBI 304 LED Version
The Wiska COMBI 304 system includes a purpose-designed LED version that combines an enclosure with an integrated lighting function.
Wiska’s COMBI 304 LED specifications include a 2.5 W light source with a rated output of 200 lumens. The LED version has different external dimensions and electrical characteristics from the standard empty junction box.
This option may be relevant where a compact enclosure and local lighting function are both required. It should be selected as the appropriate complete product, rather than assuming a standard COMBI 304 can be converted simply by fitting any replacement lid.
Wiska COMBI 304 Rotary-Switch Version
Wiska also offers COMBI 304 variants with an integrated rotary switch. These provide a compact enclosure and switching arrangement for suitable applications.
Options include selected two-pole on/off and other switching configurations. The exact electrical ratings, switching functions and suitability for isolation must be verified for the specific product.
A rotary-switch version should not automatically be treated as a suitable safety isolator for every circuit. Confirm the required isolation function and relevant electrical specifications before installation.
Can the Wiska COMBI 304 Be Used with SWA Cable?
Wiska provides specific COMBI 304 installation arrangements involving armoured cables and an appropriate earthing spring or compatible termination components.
However, the COMBI 304’s compact dimensions mean that cable bending space, gland dimensions and connector clearance require particular attention. It may be more practical to use a larger enclosure where significant armoured cable terminations are involved.
For suitable products, explore our Wiska SWA cable glands. Always verify the complete termination and earthing arrangement rather than choosing a gland by thread size alone.
When Should You Choose a Larger Wiska COMBI Box?
The circular COMBI 304 is useful where compact dimensions are important, but it may not be the best choice for every wiring arrangement.
For additional cable-entry positions, compare the COMBI 308. For a different elongated format, consider the COMBI 310. Larger COMBI 407 and 607 models provide different internal dimensions and cable-entry arrangements.
Our Wiska COMBI buying guide compares the main enclosure sizes, dimensions and typical selection considerations.
Installation Checklist for the COMBI 304
- Confirm the correct COMBI 304 version, including any integrated LED or switch function.
- Check the dimensions and available internal wiring space.
- Select the appropriate membrane entry or compatible cable gland.
- Check cable outside diameters and connector ratings.
- Use the designated external mounting feet.
- Protect the lid seal and correctly secure the bayonet cover.
- Check whether any special earthing, switching or isolation requirements apply.
- Follow the manufacturer’s instructions and applicable electrical installation requirements.
Official Wiska COMBI 304 Technical Information
For technical drawings, product options and manufacturer guidance, visit the official Wiska COMBI 304 system guide.
You can also consult the Wiska COMBI 304 BK technical data sheet for the standard black enclosure.
Electrical4Less – Supplying Wiska to UK Electricians
At Electrical4Less, we supply Wiska junction boxes and electrical installation accessories to electricians, contractors and customers across the UK. Our trade counter at 9 Seagrave Road, Fulham, London SW6 1RP provides a local collection point alongside our online ordering service.
Electrical4Less is a member of both the Independent Buying Association (IBA) and the Electrical Distributors’ Association (EDA), supporting our position as an independent electrical wholesaler.
In 2026, we were recognised as a Website of the Year finalist at the London Chamber of Commerce SME London Business Awards and shortlisted for Best Wholesaler (1–5 Branches) at the Electrical Wholesaler Awards. These recognitions reflect the continued development of our trade and online services.
Frequently Asked Questions About the Wiska COMBI 304
Explore our full Wiska COMBI junction box range for alternative sizes and accessories.
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