A junction box is the central point where cables from sockets, switches and lights meet. This is the place where conductors are connected and split between circuits. Most electrical faults start with a bad joint inside the box: overheating, arcing, unstable contact, short circuits. In older buildings on Targowek and Praga we often open junction boxes and find twisted connections wrapped in tape that has been there for decades — asking for problems.

Cost of the work

The cost is based on how many connections are inside the box and how complicated the circuit is. A basic box with 2–3 cables is straightforward work. A more involved box with two-way switching and several groups needs more time. All electrical service prices are listed in the table.

How the work is done

1. We disconnect the circuit and check it with an indicator.
2. We open the box and identify each cable (supply, sockets, lighting, switches).
3. We strip the conductors to the proper length.
4. We make the connections: live to live, neutral to neutral, earth to earth — using WAGO connectors, crimp sleeves or solder.
5. We check the circuit logic: the switch must interrupt live, not neutral.
6. We arrange the wires neatly inside the box and close the cover.
7. We turn the power back on and test every connected point.

Common problems in junction boxes

• Twisted joints without connectors — they oxidise, heat up and lose contact.
• Aluminium twisted straight to copper — a galvanic pair that speeds up corrosion.
• Live and neutral mixed up — the switch disconnects neutral while live stays permanently on the lamp.
• No earth connection — the PE wire is simply cut off or left loose.
• Overfilled box — too many cables, the connections do not fit, the lid cannot close.

Warning: work inside a junction box means dealing with several circuits at the same time. One wrong connection can take out multiple points or cause a fire. Do not risk it — call an electrician.

What to prepare

• Show us where the junction box is — sometimes it is hidden under wallpaper or plaster.
• Explain the issue: what stopped working, what sparks, what cuts in and out.
• Make sure we can access the consumer unit.
• If the box was covered with plaster during a renovation, tell us in advance.

A real case from Warsaw

A client on Praga Polnoc lost the hallway light and one socket in the living room. The breaker had not tripped. We located the junction box behind a wardrobe — inside there were three twisted joints wrapped in tape from the 1980s. One aluminium-to-copper twist had completely oxidised and lost contact. We took all the joints apart, stripped the cables and reconnected everything with WAGO connectors (using aluminium paste). Every circuit tested properly — both the light and socket were working. The client then asked us to inspect a second box in the bedroom — we redid that one as well. The whole job took about an hour (compatible with Legrand, Schneider Electric, ABB and similar).

Frequently asked questions

Book junction box wiring

We wire and rewire junction boxes all over Warsaw. We replace twisted joints with proper connectors, fix broken connections and test circuits. Get in touch — we will come over and put it right.