Junction Box Enclosures Selection Guide
A junction box is a splice box that encloses and protects cable connections where cables are joined or branched in an installation. Surface-mounted, transparent and IP-rated types.
What is a junction box? A junction box (buat) is a splice box that, at the point where cables are joined to each other or branched off in an electrical installation, encloses and protects these connections. The splices are made with terminal blocks or connectors; the cover closes the connections against contact and external influences. They come in flush-mounted and surface-mounted types; in damp and outdoor environments, junction boxes with a high IP rating are chosen.
This guide explains what to look at when choosing products in the Junction Box Enclosures category.
Types of junction boxes
The junction boxes in this category are for surface mounting.
- Surface-mounted opaque junction boxes: square, rectangular and round boxes with an ABS body and a screw-on or snap-on cover. On knockout models, the entry point is opened by breaking it out of the body. Deep types offer a taller body on the same base size; for example 120x120x70 mm and 120x120x140 mm.
- Junction boxes with transparent cover: boxes with an ABS body and a transparent screw-on cover; Bemis has IP44 and IP67 series.
- Junction boxes with plugs: the cable entries have flexible plugs. In the Çetinkaya Pano product table, these junction boxes are given as IP44, IP54 or IP65 depending on the model.
- Aluminum junction boxes: the body and cover are aluminum; models with hinged covers are available.
- ATEX Ex-Proof junction and push button boxes: aluminum junction boxes for explosive atmosphere zones, and push button boxes such as 1-, 2-, 4- and 6-button versions.
How to read the IP rating
The IP code is defined in IEC 60529; the first digit indicates protection against solid objects and dust, and the second digit protection against water. The following ratings appear in the products in this category:
- IP44: Protected against solid objects larger than 1 mm and against water splashing from any direction.
- IP54 and IP55: Protected against dust; dust ingress is not entirely prevented. IP54 is protected against splashing water, IP55 against water jets.
- IP65: Dust-tight, protected against water jets.
- IP67: Dust-tight, protected against temporary immersion; the test lasts 30 minutes at a depth of up to 1 m.
The water ratings up to 6 include one another; the digit 7 does not by itself include protection against water jets. In a place washed with pressurized water, check that the water jet rating is also stated in the product data; the required rating is determined by the project and the manufacturer data. The cable glands to be fitted to the entries and the blind plugs for any unused holes must be selected to match the rating of the junction box.
How to choose size and depth
In product names, the base dimensions and depth are written in millimeters (such as 110x110x70); for round junction boxes, the diameter is given (Ø70, Ø80). Expressions such as 8 outlets in TP Elektrik product names indicate the number of cable entry and exit points.
- Number and type of terminal blocks. The junction box terminal blocks to be used inside and the number of conductors to be spliced determine the base size.
- Number and outer diameter of cables. The number of entries and the gland size follow from this; if the side face height is not enough for the gland diameter, a deep type is needed.
- Bending allowance. For thick cables, the space for the conductor to turn inside the box and reach the terminal block is taken into account.
- If a device will go inside. Parts such as a fuse module, cover hinge and push button cover are in the junction and combination box accessories category; for more switchgear, see the panels category.
Housing material and explosive atmospheres
An ABS housing is insulating; at Bemis and TP Elektrik, halogen-free series are listed separately. For aluminum junction boxes, the TP Elektrik product data gives the housing as aluminum injection casting with stainless screws, and states a housing earth connection; connecting a metal housing to the protective conductor is done according to the project and the manufacturer data.
For the Ex-proof series, the Bemis product data states Zone 1, Zone 2, Zone 21 and Zone 22. Zones 1 and 2 are explosive atmosphere zones caused by gas, vapor and mist, and Zones 21 and 22 are caused by dust. Equipment is selected according to the facility's zone classification and the marking on the product label; the IP rating alone does not mean suitability for an explosive atmosphere.
Brands in this category
- Bemis: opaque and transparent-cover ABS junction boxes, halogen-free series, aluminum junction boxes, ATEX Ex-Proof junction and push button boxes.
- TP Elektrik: ABS junction boxes with the number of entries written in the name, transparent-cover junction boxes with and without gland entries, aluminum junction boxes.
- Çetinkaya Pano: knockout, plugged, plugged with glands and deep ABS junction boxes.
Akiş Plastik lists surface-mounted square junction boxes.
Order notes
- Products are sold per piece.
- If you need glands and blind plugs, check the product contents; models without gland entries are indicated in TP Elektrik product names.
- Akiş Plastik junction boxes are listed as made-to-order items; the delivery time is confirmed with the order.
- You can find the product directly by typing the product code (such as BB1-0531-0063, 3310-213-0077 or ÇP 1040) into the site search.
Junction Box Types and Selection Comparison Table
| Junction Box Type | Mounting and Cover Design | IP Rating and Material | Typical Application | Category Link |
|---|---|---|---|---|
| Flush-Mounted Junction & Wall Box | Recessed in masonry/concrete or drywall | IP20 – IP40 · Halogen-free / PVC | Residential and commercial in-wall cable branching and switch boxes | Junction Box Enclosures |
| Surface-Mounted Weatherproof Box | Screw cover or gasketed snap-on lid | IP54 – IP65 · ABS / Polycarbonate | Parking structures, factories, facades and cable tray branch points | Junction Box Enclosures |
| Terminal / Glanded Junction Box | Integrated membrane or PG/Metric gland entries | IP65 – IP67 · Impact-resistant body | Sensor, luminaire and motor splicing in damp or dusty industrial zones | Junction and Terminal Boxes |
Frequently asked questions
What is the difference between an IP44 and an IP67 junction box?
An IP44 junction box is protected against solid objects larger than 1 mm and against water splashing from any direction; it does not prevent dust ingress. An IP67 junction box is dust-tight and protected against temporary immersion; the test lasts 30 minutes at a depth of up to 1 m. IP67 does not by itself include protection against water jets. Both ratings are valid only when the cable entries are closed with glands or plugs matching the junction box's rating.
What is the difference between knockout, plugged and gland-entry junction boxes?
The difference is the form of the cable entry. In a knockout junction box, the thinned entry points in the body are broken out to open them, and a gland or plug is fitted to the entry separately. In a plugged junction box, the entries have flexible plugs. A junction box with gland entries has ready-made entry points in the body for glands; whether the gland comes with the product is checked from the product contents. On models without gland entries, the hole is opened during installation.
How is the size of a junction box chosen?
First the number and type of terminal blocks to be used inside are determined, then the number and outer diameter of the incoming and outgoing cables. The base size is chosen according to the terminal blocks and the bending allowance of the cable inside the box, and the depth according to the gland diameter and overlapping conductors. There are series with a deep type of the same base size; the third dimension in the product name gives the depth.
Are there round junction boxes and floor junction boxes in this category?
The category has surface-mounted round junction boxes; in product names the diameter is given with values such as Ø70 or Ø80, or as diameter and depth such as 70x40 and 85x45, and there are snap-on cover, screw-on cover and plugged types. Floor junction boxes embedded in the ground and flush-mounting boxes are not listed in this category. When choosing a round junction box, look at the number of entries and the IP rating as well as the diameter.
In which zones is an ATEX Ex-proof junction box used?
The product data of the Bemis ATEX Ex-Proof aluminum junction and push button boxes in this category states Zone 1, Zone 2, Zone 21 and Zone 22. Zones 1 and 2 are areas where an explosive atmosphere can form because of gas, vapor or mist, and Zones 21 and 22 because of dust. The suitability of a product for a specific facility is assessed according to the facility's zone classification and the marking on the product label.