Is 1.5mm Wire and C20 Fuse Safe for 5.3kW Split Air Conditioner?

Welcome,

I want to purchase an air conditioner for a 50m2 flat, split type.
The power consumption declared by the manufacturer will be in the range of 1,1kW-1,4kW.

The company installing the air conditioner suggested that I prepare a 1-phase electrical installation based on a 1.5mm2 cable and C20 protection.

I am not an electrician, but this seems to me to be a gross error in the art....
Is it not the case that if a wire of this thickness is set on fire, this C20 will not work? Shouldn't the 1.5mm be protected with a 10A fuse?
If I am thinking wrongly, please give me suggestions.
It seems to me that such an air conditioner should be fused with min. C16 and wired with 2.5mm or even "thicker" - 4mm and a C20 fuse.

One last question:
Is a 2.5mm wire fused with C20 a good idea, or is it absolutely forbidden and should be C16?

Thanks.

Hello, please give details of the air conditioner or model,air conditioner company and distance from the box or length of the power cable.

Welcome,

A colleague is right that the installer doesn't know anything about electrics. If this split is 5.3kW of cooling then by eye it should be taking ~1.8kW of electricity, or ~7.8A.
C10 protection and OMY 3 x 1.5mm2 cable should therefore be used.
A colleague writes that the manufacturer states a maximum power consumption of 1.4kW, or ~6.1A, which also gives C10 and OMY 3x1.5mm2. If the installer wants to run a YDY cable (wire is cheaper), the colleague can admonish them that, according to the Polish standard, inductive power receivers (including the compressor) should be powered with a "cable" type cable (it is more resistant to vibrations, which will translate into longer use of the installation over the years).

Regarding the off-topic of how many amperes what cable will withstand, 1.5mm2 with current manufactured cables will withstand 16A constant load.

Edit: The installation company should run the appliance, i.e. turn it on to maximum power and measure the current draw of the appliance with a meter to ensure the correct choice of cables and protection - I wonder what they will then come up with for an answer to the question "Sir, why did you say to give C20?".

Anonimity wrote:

The power consumption declared by the manufacturer will be in the range of 1.1kW-1.4kW.

.
It does not say that this is the maximum absorbed power, it is probably the power for reference conditions. Such an air conditioner could easily exceed 10A, just make sure there are poplar trees nearby....

I work in an air conditioning installation company and we always use 3x2.5 cable, regardless of the wattage, unless it is higher, for peace of mind.

We don't know the length of the installation and the type of appliance, but a 5.3 Kw system can take a lot of current at start-up, even about 15 - 20A, depending on the pressures in the system (unless it is an inverter system). Therefore, the choice of protection should actually be in accordance with what is stated by the manufacturer of the device. As for the cable cross-section of 1.5 mm, it is a bit thin and, for your own peace of mind, it is better to use 2.5. This may be a misrepresentation of the device documentation, as these are often reprints - translations, and it makes no difference to the translator whether the wire is a wire or a cable.

ion-tichy wrote:

can take considerable currents at start-up, even approx. 15 - 20A

Are you aware that a 0.5mm2 cable can withstand 100A for 30s? This is why cables are selected according to their power rating and not on the basis of the start-up time of the device - the insulation will not melt so quickly...
A 1.5mm2 cable can safely withstand 16A long term load. The author of the topic wrote that it is a circuit in a apartment (probably power supply from the distribution board located in it unit on the balcony), so you can safely use the selection tables for such short sections.

Problems arise when the power supply protection system (and current air conditioners have them) catches too high a voltage drop and the system resets. And even more so if the installation is short, you can pull 2.5, the price difference is small and you have peace of mind.
For now, these are academic considerations and the author of the post has fallen silent and we know very little.

Hello
If the wire is thin then a small fuse is better. My father-in-law put in a 25A fuse and when he had a phase-to-ground short circuit (the cable was 1mm2 wire, I think), and of course he doesn't have a differential, he was jerking 5kW all day long before he realised that something smelled of plastic in the boiler room. A 15m cable was making itself into an electric heater - just passing it off as a curiosity. If it's C10 and it blows out, that means it's time to take a compressor and clean the condenser. If it's C20 then we'll only find out when the air conditioner needs replacing.

So regarding all the disputes.... why do we use a class C fuse... because it's supposed to protect both the compressor and the compressor, and B is simply too weak and can blow or, in older installations, burn out. Why 2.5mm2 cable, because Polish standards do not allow for a smaller cable. If the power of the outdoor unit exceeds 4kW then 4mm2 cable is sufficient.
C16 is enough if it's a split, and C20 if multimedia. And ooo.

I installed a split type air conditioner myself , the wires are 1.5 and there is no problem

What a load of rubbish. And these are gentlemen installers, i.e. surely "electricians" with qualifications from a packet of crisps. Or is it just the ""boss"" who is qualified and stamps?

Anonimity wrote:

The company installing the air conditioner suggested that I prepare a 1-phase electrical installation based on 1.5mm2 cable and C20 protection.

I would treat such a company with the tip of my shoe in life. Your doubts are correct. The power supply for this air conditioner should be done as a dedicated circuit.
I would use 3x2.5 and protect the circuit with a 16A 30mA RCBO. Then measure whether the protection will switch off when needed.

Added after 5 [minutes]: .

Just which air conditioner has an ipz meter and can operate it?