Heat Pump Fuse Issue: Upgrading from C20 Hager to C25A or B25A Fuse for 14kW Connection Power

Hello,

I have a problem with the fuse under the heat pump.
Currently, I have a three-pole C20 hager fuse (a triple one, I don't know how it is professionally called).
Recently, during heavy frosts, this fuse blew out for me twice, it happened at night, which resulted in a lack of heating.

From what I read in the specification, the pump requires a 25A fuse. I guess this is the reason for the current one - it's just too small.
The connection power is 14kW with a fuse at the 25A box (tauron).
My question is the following. Can I use a C25A fuse? From what I was informed, fuses equal to and larger than the fuse at the meter should not be used. Can I use B25A?

Thanks in advance for your answer.

From what you write, you have too little connection power in relation to the installed receivers, which was shown by the first frosts, which forced the heating to work with more power. It will end with the application of WP in Tauron to increase the connection capacity to 16.1kW (32A).

Dude, you have an option for example:
1. Apply for power increase, e.g. to the value of 40A of pre-meter protection - in order to obtain selectivity for protection below. There may be a problem with the cross-section of the power supply cable.
Check the power supply conditions of the heat pump (type, wire/cable cross-section, short-circuit loop, etc.) to ensure that replacing the fuse with a larger one is possible.
If so, it will need to be changed to 25A.

2. No change in connection capacity, at least temporarily.
Check the power supply conditions of the heat pump (type, wire/cable cross-section, short-circuit loop, etc.) to ensure that replacing the fuse with a larger one is possible.
If so, it will need to be changed to 25A.
The downside of this solution is the complete lack of selectivity between the pre-meter protection and the outgoing protection for the receiver. However, it will keep your home warm at night.

mipix wrote:

It will end with the application of WP in Tauron to increase the connection capacity to 16.1kW (32A).

Apparently not at 32A...as it may be a bit too small to provide overload selectivity.

Thanks for the replies. I am considering increasing the connection power so that the fuse is 32A.

I understand that if I put 25A under the pump now, if there is an overload, it can knock out the electricity in the whole house and not just the fuse on the pump?

Kynio7_90 wrote:

Thanks for the replies. I am considering increasing the connection power so that the fuse is 32A.

I understand that if I put 25A under the pump now, if there is an overload, it can knock out the electricity in the whole house and not just the fuse on the pump?

In my opinion, 32A is so "contact"


Since you have the power allocation for the whole house as much as the pump itself needs, the pump protection will not work, but the protection at the meter will work.

Only if the short-circuit loop will allow the installation of a 32A fuse.

Thanks for the replies. If I want to put a bigger fuse on the pump with the current situation, then put C25A or B25A - is there a chance that B will work faster?

Kynio7_90 wrote:

If I want to put a bigger fuse on the pump with the current situation, then put C25A or B25A - is there a chance that B will work faster?

It's not important what you want to put in, only what you can put in there. It depends on the measurement parameters and the possibility of installation.
As for the characteristics, it doesn't matter B or C, both have exactly the same overload term.

You will mount 25A on the pump and in the best case, in a moment you will be running around the house with a flashlight looking for the main protection. At worst, something will start to smoke.

Ok thanks for your help, now I know everything.

Regards