I live in Pakistan and we have no electric panel or separate wires for different devices. I am going to rewire my house but before that I wanted to secure the refrigerator wire. I've been reading everywhere that there should be a 20A circuit breaker for the dedicated refrigerator line so I went to an electrical shop and asked him to give me a 20A breaker for it. He said that 20A is too high and I should get a 4A circuit breaker for it. We have a 220-240 single phase coming to our house. My refrigerator's nominal current is 1.25A (200W). The circuit wire is 7/0.29mm. I tried to object saying the breaker would keep tripping because its a big one but he said that he has been using the same breaker for his own big size refrigerator so it will work. Eventually I ended up buying it and attaching the refrigerator phase wire with it. Its been 3 days but still it hasn't tripped. So I want to know is it safe with this amp breaker? Why do we need a 20Amp breaker for it when 4Amp is working just fine?
Commonwealth countries normally use British standards in electrical wiring. For household wiring, there will be two distinct outlet from the distribution/circuit breaker board. One is 6A lines for the lighting circuits, and another one is 20A lines for all power outlet sockets. Lighting circuits are wired using 1.25 millimeter squared wires and the power outlet wires are 2.5 millimeter squared copper cross section area.
So, what you might have read from the internet is, anything connected or plugged in to the outlet socket is protected by the 20amp breakers. These breakers are rated actually to protect the wires in the house wiring, not to protect the appliances plugged to the sockets.
Properly rated fuse is already attached in your appliance power plug or embedded in its internal wiring. The 200Watts chiller is definitely consumes less than one ampere nominal current and its startup current may be three times higher, no way a 20Amps breaker will protect it unless it fully burnt and melt down.
Most advice you'll find online is for the US, which doesn't really apply to you. They use 120V, so appliances use more current for the same power, requiring more dedicated circuits. I wouldn't run a dedicated circuit for anything except the range (stove, oven, hob, whatever you call it) and hot water (if electric). Everything else is on one of a couple of general power circuits (or lighting).
"7/0.29" seems to be rated similarly to 2.5mm^2 copper, so would probably be on a 16A or 20A breaker.
The circuit breaker is (mainly) to protect against starting fires from circuit overloads. If the circuit is all 7/0.29, it can handle that current, and I would have no worries about a 16A circuit breaker.
4A is fine, but you then have a much thicker cable than needed ($$$), and will have nuisance trips if you ever try to plug something else in or add more sockets to that circuit.
The refrigerator's motor may surge current on startup, but the local electrical code will discuss whether this is an issue. Anyway, this is beside the point.
The point is, breakers protect wires. Whatever is the thinnest wire in that circuit - look up what amperage is permitted on that wire - the breaker should be no larger than that.