Wago 221 Junction Box for flex wire 3 core, 4 core or 5 core [compact]

Electrical safety warning:

Messing with electrics is dangerous and kills. Please don't attempt to use this junction box if you are not familiar with electric safety procedures and regulations in force in your country. Your safety is not my responsibility.

Description:

I needed a junction box for a 4-core flex wire and instead of going to the shop and buying one, I decided to spend a few tens of hours and a chunk of filament in prototyping to design and build my own. If you are lurking this site, you'll understand.

This is a compact variation of the initial model, which as it turns out is not significantly smaller… but I couldn't decide which one I prefer, so I'm actually using both.

This is the compact version.

If you would like to view my other enclosures for Wago connectors, please see below:

• Compact 2x M3 screws (this one)

• Compact model for 3 wires and Wago 212-413

• In line enclosure for Wago 212-2411

• Inline enclosure for Wago 212-2411 with screw holes

The standard version has 4x bolts holding the lid and therefore a slightly different internal configuration due to the bolt supports.

• Holds regular wago 221 2-way connectors (221-412: https://www.wago.com/gb/installation-terminal-blocks-and-connectors/splicing-connector-with-levers/p/221-412). The connectors support single core and multi-strand wire, so technically there is no need to add bootlace ferrules. Personally I prefer to have them but I understand there's pros and cons to having them. Your call.

• Models available for 3, 4 or 5 core 1mm2 flex wires (318*Y) with corresponding wire hole sizes. Other types of wires (different conductor section or insulation) will require adjustment to the wire entry holes

• Variations available for bottom or side wire entry (bottom-side, bottom-bottom, side-side)

• The enclosure was designed for multi-strand flexible copper wires. It probably won't work for rigid single core wires due to space and routing, and the wire entry hole is not suitable for twin&earth. The latter is easy to fix. The former requires some experimentation.

• The lid attaches to the box using M3 threaded heat inserts (these are super-nice https://cnckitchen.store/products/gewindeeinsatz-threaded-insert-m3-standard-100-stk-pcs). Bolts need about 5mm of thread minimum. 10mm work fine

Measurements

• Junction box compact 3x core: 34.48W x 52.16L x 19.31H (mm)

• Junction box compact 4x core: 44.14W x 52.16L x 19.31H (mm)

• Junction box compact 5x core: 53.8W x 52.16L x 19.31H (mm)

Whichever sides have wire entry holes take another 1mm for the round lip, so width and length will vary up to 1mm depending on the variation selected.

Instructions

1. Be patient. This is fiddly work. The enclosure was designed to be compact, meaning that there is little space to work.

2. Slide in the cable ties to secure the wires, but don't tighten them. You may need to use small needle nose pliers to fish them out, even with the rounded edge corners.

3. Slip one flex wire in, strip the outer insulation so that the cable tie will grab it. Strip each wire to length, as close as you can make it, bearing in mind that not all wires will have the same length.

   1. Once the wires are cut to length, you can slip the flex cable further into the box and connect the wires to the wagos outside the box. This allows for a lot more space to work.

   2. Connect the wires to the wagos, check they fit back in with the wire in the correct place. Don't tighten the cable tie yet!

4. Slip the other flex wire, repeat the procedure above.

5. If both flex wires are in place, the wagos fit into their pockets, and the outer insulation covers the cable tie support, start tightening the cable ties making sure everything stays in place. When all is in place, fully tighten the cable ties and clip the excess with flush cutters.

6. Place and screw the lid.

7. Done.

Additional design features

• Snug cable entry hole to limit dust ingress

• Slot for cable ties on the inside for cable relief

• Attachment holes for countersink screws screws

• Corner radius for cable tie to loop around easily

• Wago connectors are ‘locked in place’ so they don't move once the lid is placed