Service for our customers

Questions of our customers


On this side we want to offer you the list of the most frequent questions propounded by our clients. If you have some question or remark, you can use any e-mail address, phone number or even the form Write us which has been created specifically for this reason. We will be glad to answer you without exception.


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Circuit Protection Devices
Question: Answer:
Hallo, inform me please if you offer also the switch 220V reacting to handclapping. I mean - I clap my hands once, It switches on, I clap my hands twice, it switches off ..... If yes let me know your price and possibility to order it, evtl. give me the contact to any dealer from the Ostrava region, please.

There is not any similar switch offered by us and I don´t know if any competitor manufactures it. Should we receive such information we will contact you.

answered by:Roman Hudeček

Your protective switch switches off closed underneath the limit 30 mA (27 mA to 30 mA). The competitive current protective switches Moeler-Felten switch off already with 18 mA.


Intentionally, the adjustement is made as closed as possible to the upper limit of the switch-off current mentioned, e.g. it is the range between 25 mA to 30 mA for the value of 30 mA. But it is up to every producer (hereby I am presenting a part of our business secret). Pursuant to our experience the very high circuit oversensitiveness with the low protective switch adjustment negatively affects the unnecessary fall-out losses of electrical appliances. It is enought then to have wet "forgotten plaster" on the conductor, softly increased humidity of enviroment .... etc. and the current protective switch switches off the circuit immediately without any danger of electrical accident or defect could be imminent... The value of 30 mA is more than sufficient to rescue one´s life and even the human beings with a high oversensitiveness.

answered by Roman Hudeček

Measuring the parameters of your protective switch I have found that the time needful for the protective switch to be switched off is 30 ms and even higher. The measerud values of that time period at one protective switch are different as well.



Switching-off speed of a protective switch depends mainly upon two facts (if we don´t take into account mechanical matters, e.g. friction of the switch-off mechanism):

a) place at the alternative current "sinusoid" at the moment when the pulse occurs to switch off the protective switch

With our frequencies, the time behaviour of the sinusoid amounts to 20 ms. If e.g. the sinusoid maximum is at the value of 40 mA and the switching-off value of the protective switch is adjusted to be 30 mA, and the moment of the pulse for switching-off is in the second half of the first (upper) half-wave, than the coil reaction to the pulse moment comes in the second (lower) half-wave. In the meantime, the time period thus the delay up to 10 ms can elapse. That means this big difference can appear between two successive measurements of only one current protective switch !!!

b) intensity of the current which is able to induce the switching-off coil

the standard CSN EN 61 008 concerning the current protective switches specifies clearly the maximum time limits for the switch-off speed, in dependence on the current IN :

for 1 x IN the time necessary for switching-off is max. 0,3 s, i.e. 300 ms
for 2 x IN the time necessary for switching-off is max. 0,1 s, i.e. 100 ms
for 5 x IN the time necessary for switching-off is max. 40 ms

- e.g. for the protective current switch value 30 mA it is:
for 1 x IN - 30 mA = 30 mA not later than within 300 ms 
for up to 5 x IN - 30 mA = 150 mA, when it must react not later than within 40 ms.

Thus the standard takes into consideration the above delays under a) when with the maximum five-times load it provides the time up to 40 ms. the same is valid for coil induction when with IN the time can be up to 300 ms.

The standard respect the switch-off time period sufficient the human being´s life even with a higher oversensitivenes to be rescued.

The switch-off time period being measured by you corresponded to the CSN standard. It depended on the load to which the current protective switch was expired, furthemore on the moment of the sinusoid condition, your measuring instrument accuracy etc. The difference in the switch-off time period at one current protective switch measured by you, I have explained under item a)


answered by Roman Hudeček

How will your protective switches react after the longer operation? Will the value of switching-off current be increasing or decreasing?


This question can be answered explicitly, roughly speaking. After a long operation period, the current protective switches working based on interruption of the magnetic field balance have a tendency to oversensitiveness, thus to deviation under the originally set values. This is caused by gradual loss of magnetism. The loss caused by "ageing" is almost negligible but it exists. For that reason we set up higher switching-off values.

The adjustment of current protective switches is done on a special stand either by increasing or decreasing of magnetism (when you visit us we will be fond to show it to you)

The above adjustment principle is connected with another problem of current protective switches of that type - if these protective switches are located closed to a very strong magnetic field (see protective switch located closed to a electric locomotive), the over-adjustment in both directions - up and down - can occur. This is to be taken into account when mounting.

These two above problems can be removed only by another principle of current protective switches, the electronic one. We are working at its readiness for manufacture !!!


answered byRoman Hudeček

In addition to the circuit breaker, we have begun to buy the current protective switches at your company. We expected that these switches would function without any defects in the range of their nominal values , i.e. the switching-off one (residual current 30 mA and the time period necessary for timed release of the current protective switch). During the first measurement of a two-poles protective switch I was surprized by the switching-off current values measured. These values were higher than 30 mA and they had different value at every measurement. In the next delivery, the problem with the higher switching-off current has not occured.


This problem was caused by the bad material of the protective switch transformer core. That material didn´t show the same magnetism on its periphery, due to the different density of the core material. Unfortunately, it didn´t occur to us before to check this feature. But it concerned the only defect series. Since that time, such problem has not appeared.

answered by Roman Hudeček

Have you any branches in the Czech republic?


No, we haven´t. The whole Czech republic is supplied from one central warehouse in Sudomerice nad Moravou.

answered byRoman Hudeček

How long is the delivery period for the circuit breakers?

Thanks to big stocks and the services of dispatch by means of PROFI PARCEL, our delivery periods are mostly within 48 hours.

answered by Roman Hudeček

Do you organize regular deliveries over the Czech republic?

No, we don´t, our deliveries are only casual.

answered by Roman Hudeček

Have you changed your prices in the course of the years 1999 and 2000 ?

No, we haven´t changed our prices, nor for the inflation reason either. Because of the increasing sale, our overhead costs are decreasing and thus the difference is balanced.

answered byRoman Hudeček

Why you don´t use the indication on your circuit breaker or on the cases that your product has received the Certificate of the Electrotechnical Test Institute of the Czech republic, and the indication that your product has complied with the conditions for the assessment of conformity with our regulations, evlt. Conformity Declaration for Europe?

It is our mistake because we are entitled to use those indications due to our Certificate of the Electrotechnical Test Institute as well as due to the declarations on conformity assessment. To print this indication onto any products is not compulsory pursuant to the Czech laws. We have underestimate the importance of putting these indications onto our products and as found by us, it is essential for trust in our products and for our business success. This mistake is going to be corrected as soon as possible

answered by Roman Hudeček

What is your approach to the customer in the event of a rightful claim ?

We replace a piece for a piece.

answered by Roman Hudeček

What is the purpose of cut-outs under the switch-off lever of the circuit breaker and above the lower terminal?

They are intended for plastic labels (user´s and schematic descriptions of the circuit breaker) which shall be put into these cut-outs. These labels will be delivered as an integral part of the circuit breakers as soon as possible.

answered by Roman Hudeček

Will you have also circuit breakers with colour levers according to the values of nominal currents?

Yes, we will. They will be involved into the series production in December 2000 .

answered by Roman Hudeček


Do you prepare the circuit breakers with 10 kA ?

Yes, we do. They are under examinations.  

answered by Roman Hudeček

Are your electrical instruments compatible as to their height with other eletrical instruments used at the switchboards, if attached to the DIN strips?

They are compatible with all the instrument which correspond to the height 44 - 61 mm from the DIN strip range.

answered by Roman Hudeček

How can be the circuit breakers, switches and current protective switches interconnected by means of strips with other el. instruments used at the switchboards, if attached onto the DIN strips?


By means of "reed" interconnecting strip for modules with the width of 17,5 to 17,8 mm and with the terminal height of 15 - 21 mm from the DIN strip range.

answered by Roman Hudeček

Have you got ISO 9001,9002 ?

Not yet, but we are preparing ourselves.

answered by Roman Hudeček


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