WAGO belongs to the so-called. spring terminals and are designed for quick connection of wires of power electrical wiring. Due to its ease of use, combined with the ability to quickly form a reliable and, together with so, a durable connection, they have won a lot of fans and are widely used in everyday practice.
However, along with positive responses, there is also a large number of negative reviews on the Internet. Their essence boils down to the fact that the parameters declared by the manufacturer are not achieved and the WAGO terminals quite often simply burn out. Why did such publications appear and are there any rational grain in them? Let's try to figure it out.
Possible reasons for refusal
The high popularity of the terminal blocks leads to a steady supply of cheap WAGO terminals. Due to unpredictable quality, potential patent infringement and other similar considerations such elements are not considered and in what follows we will assume that we are talking only about original products.
Taking into account the country of origin - Germany, we believe that the manufacturer honestly fulfilled all the required inspected and tested its products in full compliance with the requirements of the relevant regulatory documents.
Any element can fail. The reasons for refusal can be varied, but they can be reduced mainly to the following two cases:
- operation in abnormal mode;
- knowingly or unintentionally violating the installation rules.
Spring terminal device
To understand the possible causes of failure, let's get acquainted with the terminal design. It is based, regardless of the version (an example is shown in Figure 1), is a flat spring clip made of high rigidity chromium-nickel steel, additionally equipped with tin coated. The clamp is mounted in a plastic case and is controlled by a pivoting lever. In the working position due to the large contact area and high pressing force, a time-stable electrical connection between two wires with minimal transient resistance R.
The ignition of such an element in normal mode is possible only if the power value P = I ~ 2 * R, where I is the current through the terminal, becomes greater than a certain threshold.
If we assume that the current I does not exceed the manufacturer's recommended limit value, then the failure is determined by an extremely unacceptably large R.
Causes of increased contact resistance
Contact resistance becomes unacceptably high if:
- the area of interaction between the contact and the conductor is too small - most often this is observed in the case of an attempt to install WAGO on an unstraightened conductor, Figure 2;
- if dirt gets between the contact and the conductor, i.e. the wire was not properly processed before installation;
- the surface of the wire is oxidized, Figure 3;
- an aluminum wire without protective paste is inserted into the terminal.
All these cases represent a direct violation of the installation technology and it is not surprising that, when exposed to the maximum load, the terminal block becomes charred and even ignites.
Conclusion
The WAGO terminal is a reliable, time-tested, high quality component. The main guarantee of its long-term and trouble-free use is compliance with the technical operating conditions and the fulfillment of all technological requirements of the installation, without exception.