Reading an electrical panel, module by module

A domestic electrical panel is read from the incomer to the outgoing ways. Each module has a precise role.

The incomer and the main RCD

After the meter and the main switch, a 300 mA RCD monitors the whole installation: it trips if current leaks to earth.

The 30 mA RCDs

More sensitive, they protect the higher-risk circuits: bathroom, washing machine, tumble dryer, dishwasher. Their type (AC, A, F, B) indicates the forms of fault current they detect; electronic appliances require at least type A, a charging point often more.

The breakers

One breaker per circuit. It is marked with a letter and a number, for example C16: the curve (B, C, D) and the rating in amperes. The rating depends on the cable size: 16 A for 1.5 mm², 20 A for 2.5 mm² in common cases.

Cable size	Max. usual rating	Typical use
1.5 mm²	16 A	Lighting
2.5 mm²	20 A	Sockets, oven, washing machine
6 mm²	32 A	Single-phase hob, charging point

The other modules

Surge protector, day/night contactor, latching relays, timers and modular sockets often complete the panel.

With Disjoncto. Slide the modules along the rails: the single-line diagram and labels follow.