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How to choose the current size of household circuit breakers in 2020?

By:Nader Updated:September 08,2020 18:25PM

All electrical appliances are added /220(V)×1.5 power vested open space capacity, look for the nearest similar specifications can be.

Household electricity switch box configuration:

  • the master switch (GFCI) 40a,
  • the air conditioner switch (single-pole air switch) 20a (per 1),
  • a light switch (single-pole air switch) 10a,
  • the socket (air switch) 20

A air switch household power mains for the switch or the branch line protection switching. When the line residential or home appliance short circuit or overload, it can automatically trip off the power, so as to effectively protect these devices from damage or prevent the accident; general household with two-pole (i.e., 2P) as the total power protection air switch, unipolar (1P) for the branch protection; rated current selection if the air switch is small, the air is easy to frequent trips the switch, causing unnecessary power outages, such as the selection is too large, then not achieve the desired protective effect, thus decoration air switch, the correct choice of the rated capacity of the current size is important. Generally small air switch specifications mainly in the area of ​​the rated current 6A, 10A, 16A, 20A, 25A, 32A, 40A, 50A, 63A, 80A, 100A and so on;

How the average family or checking the total load current total value it?

1. First, the calculated value of the branch current

1.1. Purely resistive load, such as light bulbs, electric heaters, etc. directly marked with a voltage divided by the power to give the formula I = power / 220v; 20w bulb for example, the branch current I = 20W / 220 = 0.09A. Electric fans, electric irons, electric blankets, electric water heaters, electric heaters, rice cookers, cookers, vacuum cleaners, air conditioning as the resistive load.

1.2.  Inductive load, such as fluorescent lamps, televisions, washing machines, etc. slightly more complicated calculation, the power consumption to be considered, but also consider the particular computing power factor, for purposes of estimation, the author gives a simple calculation, i.e. inductive load in general, according to which indicate the load calculated power can be doubled, e.g. 20W fluorescent indicate branch current I = 20W / 220v = 0.09A, doubling of 0.09A * 2 = 0.18A (calc accurate than 0.15A ., multi-0.03A)

2. Total load current is the sum of the branch currents; know current and total current branch, the branch can select switch and total air brake air switch, fuse total, the total meter and the specifications of each branch wires or checking electrical specifications of these components have been designed for compliance with safety requirements;

3. In order to ensure safety and reliability, the amount of electrical componentsUsually a given operating current should be greater than 2 times the maximum desired load current; In addition, in the design, the choice of electrical components, also taking into account the possibility of increased electricity load after leaving a margin for future needs; The following table gives the rated current of several common residence and the main computational load switch: