DigiTOP VP-50A M2W voltage relay (50A, white indicator)

The more powerful electricity in the house, the more expensive the price of a network error - and the more important reliable protection at the input. VP-50A M2W is designed for just such a house: with an electric stove or oven, underfloor heating in several rooms, a powerful air conditioner and a boiler, which can work at the same time. The rating of 50 A corresponds to approximately 11 kW of total load - this is already a serious level, beyond which only the transition to a three-phase circuit is possible.

Why a relay if there are already circuit breakers in the shield?

A logical question that should be closed immediately. A circuit breaker protects the wiring from overload and short circuit - that is, it saves the cable from ignition. But it does not react in any way to the fact that the network suddenly became 300 V instead of 220: for the circuit breaker this is a "normal" current, it will not work, but the equipment will burn out. A voltage relay closes this gap - it monitors not the current, but the voltage, and turns off the power when it becomes dangerous. These are different devices with different tasks, and in the right panel they work together, not instead of each other.

How it protects

The relay measures voltage in the range of 50–400 V at two thresholds: upper 210–270 V, lower 120–200 V. In case of overvoltage, the shutdown is instantaneous — 0.02 seconds. In case of a drawdown in the zone of 120–170 V, a one-second delay is provided so as not to jerk the equipment due to safe short-term dips, and below 120 V — again an instant shutdown. The zero transit function insures against the most serious accident: a break in the neutral conductor, when all the expensive equipment in the house is at risk at the same time. The relay also works correctly with unstable network frequency.

Installation and setup

Installation on a DIN rail, 2 modules of 17.5 mm, immediately after the input circuit breaker. It is especially important to set the re-activation delay (5–600 seconds) with such a load with a margin: it is behind the compressors of the air conditioner, refrigerator and boiler, for which a sharp restart under load is the path to premature failure. Thermal protection operates at 70°C. The indicator is white, the warranty is 5 years. Not sure whether 50 or 63 And take under your shield - send a list of powerful consumers, we will calculate together and we will not let you overpay or take too little.

How to estimate the shield load yourself

It is easy to calculate the required rating even without an electrician. Write down the power of all devices that can actually work simultaneously during peak hours: an electric stove (usually 4–7 kW), a boiler (1.5–2 kW), an air conditioner (1–2 kW), a washing machine, a kettle, lighting. Add them up, divide the sum by 220 - you will get an approximate current in amperes. If it turns out to be about 45–48 A, you should not take a relay "close" to 50 A: when several devices are started simultaneously, short surges of current above the calculated value are possible, and it is better to have a margin. In this case, it is more logical to either take a model with a rating of 63 A, or think about a three-phase input that will distribute the load across three phases.

What if 50 A is not enough?

It happens that the calculation gives a current close to 50 A or slightly higher. You can only increase the single-phase circuit up to 63 A - this is a physical ceiling. If the load consistently rests against this limit, the right solution is not a more powerful single-phase relay, but a transition to a three-phase input: it divides consumers into three phases, and a separate relay of a smaller rating is installed on each. Such a circuit is both more reliable and has a reserve for the future. We will tell you at what point it is more profitable to stop at 50 A, and when it is time to plan a three-phase panel.