How to choose a household distribution box?
Renovation, especially in the second renovation of the old house, often involves the transformation of the distribution box. Let's talk about how to make a household distribution box affordable and safe?
When carrying out the transformation of the distribution box, we must first consider the safety of this distribution box. An ideal distribution box should have the following configuration.
Number of loops
The optimal number of distribution box circuits (electric gates) should be 1+X+Y+Z—1 refers to the main switch; X refers to the number of rooms used to control the ordinary socket of each room; Y refers to The number of high-power electrical appliances is used to control every high-power electrical appliance (electric appliances that need to use surface-mounted circuit breakers or 16A three-hole sockets are all high-power appliances); Z refers to the number of lighting circuits (2~3 for lamps) For a loop, generally use one loop).
Number of poles
Household circuit breakers are divided according to the number of poles, only three: 1P, 1P+N and 2P. The difference between these three types of poles is that the 1P circuit breaker can only control the on and off of the live line and provide protection for the live line; the 2P circuit breaker can simultaneously control the on and off of the zero line, and at the same time provide protection for the zero line; 1P+N open circuit The device is somewhere in between - it can only control the on and off of the fire line, but at the same time provide protection for the neutral line and the live line. Therefore, it is also known that the 2P circuit breaker is the best, only the 1P+N.
Function selection
The air switch comes with two protection functions, overload protection and short circuit protection. In addition to the protection functions, it needs to be added by additionally installing accessories. Two types of accessories commonly used in the home are leakage protectors and "overvoltage and undervoltage release". The former is used on the circuit breaker of each socket (including the ordinary socket and the three-hole socket); the latter only needs to be installed on the main switch.
Practicality
The distribution box configured according to the previous method can guarantee absolute safety. But there are two problems:
First, the distribution box is too large;
Second, the price of the distribution box is too high.
The reason for these two problems is that the number of circuits in the distribution box is too large and the number of poles is too large. Therefore, if we want to make the distribution box practical, we must start from these two aspects. Loop Reduction The ideal number of loops is 1+X+Y+Z, where the main switch and lighting loop cannot be changed—because they are few in number, they are lost. Y (high-power electrical) circuits can't be changed either - high-power appliances must use separate circuits and must be retained unless they are not used. So, what we want to reduce is the X (number of rooms) loop.
Be careful when merging, be sure to merge the two adjacent rooms, otherwise you will waste more wires during the renovation.
Extreme number reduction
The number of poles of the circuit breaker is the main source of width - 1P and 1P+N are open and the width is half of the 2P open. If the leakage protector accessory is added, it may be one-third of the 2P leakage switch (the width of the leakage protector accessory is related to the rated current; the width of the open contact is only related to the number of poles). Therefore, in addition to the main switch need to use 2P open, high power socket circuit need to use 2P leakage switch, the other circuit can use 1P or 1P + N circuit breaker (the socket circuit is installed with leakage protector on the circuit breaker).