How to build circuits and check the lines
WhereElectricsPanel and circuitsthe Circuits tab
Steps
- Click Assign devices (the button shows how many devices still have no circuit): the editor builds circuits by room and by kind (lighting, sockets, wet areas, dedicated lines), and the panel from them.
- Look at the Check column: each line has a tag with the most important remark: cable not selected, cross-section too small, ΔU above the limit, not routed. Hover over it to see all of them. Above the table is a summary: OK, attention, errors.
- Click a row, and the properties of the circuit's protective device open on the right. Where a line does not add up, there is auto: under the Cable field if the problem is the cable, or in the Check section if it is the breaker. The button sets the rating, curve and cable at once.
- Click Route all cables or Route on the plan in the circuit properties.
Circuits under one RCD are gathered under its row, for example .
What is set for a circuit (in the properties on the right; the Routing section exists only on the Circuits tab)
| Field | What it is |
|---|---|
| breaker current | |
| B, C or D for a breaker and an RCBO | |
| what the line feeds and with which cable | |
| lighting, sockets, wet area, dedicated line, three phases; breaker or RCBO | |
| in plaster, in conduit or corrugated pipe, in an insulated wall (with and without conduit); the permissible current depends on it | |
| how many lines run side by side: in a bundle the cable carries less | |
| the circuit's demand factor and the temperature along the route (attic, boiler room); if empty, 1 and 30 °C | |
| with a three-phase supply; Auto: distributed automatically | |
| where the auto route leads the line: along the ceiling or in the floor |
What is set for a device (device window, Electrics block): the circuit, the power and the Starting current from the datasheet of a device with a motor (air conditioner, pump). For an outlet for an air conditioner without a starting current the field is highlighted, and for the circuit the summary shows no starting current.
What is set for the supply (the Supply row above the table): Fault current (highlighted while empty), Breaking capacity, Board demand factor, I²t (from the breakers' datasheet). Under the More button:
- Feeder cable: the cross-section (4–35 mm²), copper or aluminium, and the length from the floor board or the building's main board to the panel. The drop on it is added to each line, and ΔU from building board appears on the right. Next to it you can see how much the cable carries in conduit (method B2). A cable that holds less than the supply breaker, or aluminium thinner than 16 mm² (PUE, cl. 7.1.34), gives a remark.
- Demand by kind: the default demand factor for lighting, sockets, wet areas, dedicated lines and three phases. A circuit with its own demand factor uses its own.
What is checked
- the cable holds the breaker current with the chosen routing, bundle and temperature (GOST R 50571.5.52-2011, Table B.52.2, B.52.4, B.52.14, B.52.17), the route is not led to a device of another circuit;
- the voltage drop is no more than 3 % for lighting and 4 % for the rest, counted from the building board if a feeder cable is set (SP 256.1325800.2016, cl. 8.23);
- in a fault, the current at the end of the line is enough for instantaneous tripping of the breaker (if the fault current at the supply is set), and the cable withstands the fault energy (if I²t is set; GOST R 50571.4.43-2012, cl. 434.5.2);
- the starting current does not reach instantaneous tripping: B: 3, C: 5, D: 10 rated currents (GOST IEC 60898-1). Otherwise you will see trips on start, and auto will set C or D;
- selectivity with the supply breaker: the supply breaker rating is at least 1.28 times the circuit rating (1.45 and 1.13 In, GOST IEC 60898-1). In a fault only as a limit on instantaneous tripping of the supply breaker: more precisely from the manufacturer's curves;
- the supply RCD of type S has a leakage current of at least three times the circuit RCD currents (GOST R 50571.5.53-2013, cl. 535.3); circuits of one single-phase RCD are on the same phase;
- the leakage behind each RCD and RCBO is no more than a third of its current (PUE, cl. 7.1.83). How much has accumulated is shown in the RCD circuit header: ;
- all circuits of a room with a bath or shower are under a 30 mA RCD or RCBO (GOST R 50571.7.701-2013, cl. 701.415.1). A room counts as such by its purpose or if it has a bath, shower tray or shower cabin. Assign devices itself puts an RCBO on its own line there.
What is important to know
- The editor does not know starting currents, demand factors, the fault current at the supply, I²t, the feeder cable and the temperature: the designer sets them.
- Leakage on a line without power or a route is not counted, and the RCD properties say so.
- The thermostat of an electric underfloor heating gets its own line: 16 A, 30 mA RCBO, cable 3×2.5 (GOST R 50571-7-753-2013), if power is set for it or it is tied to a floor zone. The thermostat of a water underfloor heating gets no line.
- An outlet for an extractor fan, breather or recuperator from Water and heating goes to the lighting circuit of its room.
What is checked under the table expands the same list briefly, with links to the standards.