The choice of leakage current protection is an important point in the wiring design phase. And many will say that there are only two options for such protection: an RCD or a differential machine, and in principle they will be right. But which one to choose in order to guess at the cost, but not forget about safety?
What's the difference?
Completely different devices, in their functionality having only one similarity - current leakage protection.
RCD - residual current device detects current leakage (for example, breakdown of a phase conductor to the case) and disconnects a specific line. It can be installed both at the input and on separate circuits - a boiler, washing machine, hob or electric motors in production.
Differential switch - combined device for protection against current leakage and short circuit. In addition to the functions of a standard bag, it also has all the capabilities of an RCD, including the "Test" button on the case. The extended functionality did not affect the dimensions of the diff. machine.
Why choose a differential machine
There are several reasons:
- Saving space in the electrical room. As mentioned above, diff. the machine does not differ in size from the RCD. Of course, in a switchboard for 16 modules, this is not particularly noticeable, but in switchboards for 80 positions or more, the difference is quite noticeable, several differential automatic machines will save space.
- The main difference is the dual functionality. Always protects against short-circuit and "smells" the current leak. Convenient, rational, correct.
- Not much difference in price. Yes, the cost of the diff. the machine is more than a separate RCD, but not more than these 2 devices together. The manufacturer is also an important factor here, because Legrand products will cost much more than the same IEK.
You can also include the installation of a differential bag in this list, because it is no different from an RCD - it is necessary to install both phase and neutral wires. Only here it is not necessary to separately "throw" a jumper between the machine and the RCD.
Why do many people choose RCDs?
Some craftsmen are more used to working this way. Install the residual current device first, then the bagger, and even if a malfunction occurs, it is much easier to determine it. But this is not the case when you should take the least simple path.
The differential machine is a very convenient product, both during installation and during further operation. Once set and periodically check the serviceability of the operation by pressing the "Test" button.
But many people forget about the fact that one should constantly move forward, and this applies to the market of electrical products no less than to other industries. After all, it was possible to lay aluminum wiring like that, and make all connections with twists.
Summing up
Dif. an automatic machine is a convenient technical solution to two important points of protection of electrical circuits - from short-circuit and current leakage. The device is housed in a convenient housing that takes up little space in the switch room, its functionality is checked by the "Test" button. The cost is not much different than the sum of the prices of an RCD and a standard circuit breaker.