Open junction box (boîte de jonction): what it is, how serious, what it costs

When electrical wires are joined together, with twist-on connectors often called wire nuts (« marrettes » in Quebec), the splice must be enclosed in a box: the junction box, « boîte de jonction » in a French report. Closed by its cover, it protects the wires from knocks and contains a spark or overheating if a connection works loose.

You mostly see them in an unfinished basement, the attic and the garage. Reports say “junction box without cover”, “splices outside a box” or “exposed wiring”.

It is a safety issue: an exposed splice can cause an electric shock or start a fire. It is cheap to fix, which is why I put it under “Fix first” when a report mentions an open box or splices outside a box.

A box without a cover can be a sign of work done without an electrician. If the report notes several, or abandoned wires, it is worth having the rest of the wiring checked.

Installing the cover on a junction box: $100 to $200, or $200 to $450 for several boxes in one area. Protecting an exposed cable: $150 to $350. Safely terminating an abandoned wire: $100 to $250.

In Quebec, this work is done by a master electrician.

These are ballpark figures for Quebec, to be confirmed with quotes.

1. How many boxes are open, and where?
2. Did you see splices outside a box, or wires that lead nowhere?
3. Do these spots look like work done by the owner?

Ask the seller what electrical work was done, by whom, and whether they have the invoices.

Does your report mention junction boxes? Upload it: in five minutes, I tell you what comes first, what to have checked and what to ask the seller.

No. A junction box must stay accessible, so an electrician can check the connections. If a basement was finished over one, it needs an access panel or a visible cover.