The VA47-60M circuit breaker is an infrequent guest in an electrical panel. Usually, the more popular VA47-29 model is preferred. However, under certain operating conditions, it will be optimal to install exactly the VA47-60M.
VA47-60M KARAT: when special reliability is needed
Let's consider the key characteristics of VA47-60M and understand in which situations it is better to use it.
Breaking capacity: 6000 A
Rated ultimate breaking capacity (Icn) — this is the short-circuit current that a circuit breaker is capable of interrupting. For VA47-60M, this parameter is 6000 A.
The Icn value is indicated in the frame on the front panel of any modular circuit breaker.
According to GOST IEC
Electrical endurance — not less than 8000 operations
In GOST IEC 60898-1-2020 clause 9.11, it is recorded that this parameter is determined at a current equal to the rated current. The number of on-off cycles specified in the operating manual (not less than 8000 for VA47-60M) corresponds to switching operations at rated current.
When making and breaking at a current below the rated one, the possible number of operating cycles at which the breaker condition will remain satisfactory will increase. However, this number is not standardized.
During switching operations at a current above the rated one, the possible electrical endurance will decrease. But it is impossible to predict the exact value. It depends on the actual value of the short-circuit current and on the breaking capacity of the circuit breaker.
When is high breaking capacity needed in electrical panels?
In most home electrical panels, it is sufficient to use the VA47-29 line with a breaking capacity of 4500 A. However, in the cases described below, we recommend considering replacing VA47-29 with VA47-60M.
- High short-circuit current: when the short-circuit current exceeds one third of the breaking capacity Icn. The short-circuit current can be calculated or measured with special instruments.
- Increased reliability requirements, for example, in entrance electrical panels or in distribution panels of shopping centers.
- Intensive operation: frequent switching, overloads, and short circuits, especially with inductive load or high starting currents. Examples of such places are repair workshops and production shops.
If you consider it inappropriate to install VA47-60M throughout the entire panel scheme, then at a minimum, it should be used as the main input breaker. It is at the input where the highest operating currents and short-circuit currents are. The labor intensity of replacing the main protective device compared to group breakers is also a factor in favor of VA47-60M.
For non-residential buildings, one should be guided by the instructions of GOST
How to know if you have a high short-circuit current?
Often, it is problematic to find out or measure the short-circuit current. But there are indirect signs by which you can understand that it is high:
- The transformer substation is located nearby or inside the building. This is typical for industrial enterprises, trade and office centers, and new residential complexes.
- The transformer, supply line, and input are relatively new.
- The phase voltage is slightly above the norm (more than 230 V), and practically does not change during the day.
Conclusions
Our recommendations are aimed at ensuring your equipment operates without interruption. Let us remind you that the service life of all IEK modular circuit breakers is 15 years. However, correct calculation, selection, and operation of the devices can extend it for years.