DigiTOP VP-40A M2W voltage relay (40A, white indicator)

When an electric boiler and air conditioner are added to the apartment set of appliances, the usual "apartment" rating may no longer be enough - and this is where the VP-40A M2W comes in. This is the same reliable DigiTOP protection logic, but with a current reserve of 40 A, designed for a house or apartment with increased consumption, where several powerful devices actually work simultaneously.

Protection logic

The relay continuously measures voltage in the range of 50–400 V and maintains two thresholds: the upper 210–270 V and the lower 120–200 V. Overvoltage is cut off instantly, in 0.02 seconds, because a sharp jump is the most dangerous for electronics. Undervoltage is processed more intelligently: in the 120–170 V zone, the relay waits a second so as not to react to harmless short-term dips, and only below 120 V does it turn off instantly. Zero transit works separately - protection against a break in the neutral conductor, when the voltage in the phase can jump to destructive values and disable everything at once. Correct operation at an unstable frequency will come in handy where there is a generator.

How to choose a denomination: a short cheat sheet

DigiTOP produces a line for different currents, and 40 A is the "golden mean" between an apartment and a large cottage. The guideline is simple: 32 A (≈7 kW) - an apartment; 40 A (≈8.8 kW) - a house with a boiler and air conditioning; 50 A - when an electric stove or underfloor heating is added; 63 A - a ceiling of a single-phase circuit. The main rule is to count not "how many devices are in the house", but how many of them can actually turn on simultaneously. If you are in doubt between 40 and 50 A, send us a list of powerful consumers, and we will tell you for sure.

Assembling

The relay is mounted on a DIN rail (2 modules of 17.5 mm) immediately after the input circuit breaker to protect the entire network with one device. The re-activation delay (5–600 seconds) should be set with a margin - it is critical for air conditioner and boiler compressors, which do not tolerate sudden restarts under load. Thermal protection - at 70°C. The indicator is white, the warranty is 5 years.

One for the entire shield or on separate lines?

A question that arises almost always. The most common and cheapest scheme is one relay of the appropriate rating immediately after the input circuit breaker: it protects the entire network of the house, and this is enough in the vast majority of cases. Putting separate relays on each group makes sense only when some lines are critically important and must continue to work even when the rest are disconnected - but this is an individual shield design. For a 40-amp house, one relay per input will almost always be the right solution: it is simpler, cheaper and without unnecessary points of failure. If you have a special scenario - with a separate circuit for a server, aquarium or medical equipment - it is better to discuss the scheme with an electrician in advance. And another practical argument in favor of a current reserve: if in a year or two you plan to add another powerful device - say, a second air conditioner or a instantaneous water heater - you should not take the relay "close to you", because you will have to change it. A small stock of nominal value today saves replacement tomorrow - both money and time for a second call to the electrician.