Entry standard, everything you need to know!

Do you know how to scale the input pattern or have you ever needed to size an input pattern and were in doubt? In this article, we will show you everything you need to know to design an input standard, such as the level of electrical voltage, circuit breaker design, power and other parameters necessary for the correct design. Come on!

What is the input standard?

The input pattern is the main point of entry of electricity for consumer units since the input pattern is composed of a wattmeter which is also known as an electricity meter, a circuit breaker and the pattern box. The wattmeter has the function of measuring household consumption in kWh (power per hour). The circuit breaker has the primary function of protecting the electrical installation and is also an external switching device for the residence. The standard box has the function of protecting the components against damage such as rain, sun, unintentional contact of people in the components, etc.

Input voltage models and voltage levels

In Brazil, there are countless electric power concessionaires and each one has its own internal rules, which are based on the PRODE of ANEEL (Electricity Distribution Procedures in the National Electric System). For these reasons, there are different models of entrance patterns, for example, in iron, iron with acrylic cover, in iron pole, concrete pole etc.

Different types of input patterns for each region.

The following table indicates the levels of secondary electrical voltages provided by the electricity concessionaires in accordance with ANEEL standards.

The levels of secondary electrical voltages.

The technical information for the correct assembly and installation of the entrance pattern of the residence, will be made available by the concessionaires responsible for the distribution of electricity in your region, city or state.

How to scale the input pattern?

After all the necessary explanations to have an understanding of what is the input standard and what are the levels of electrical voltages provided by the concessionaires, we will dimension the input standard.

The first step is to carry out a survey of the amount of power per equipment of the residence, to know which will be the correct circuit breaker to be used in the input standard. In cases where the homes do not have an electrical project, this survey of the amount of power per equipment can be done through a conversation with the customer, asking questions about the possible electrical equipment that will be used in the installation. It is important to know if the installation loads are 127 Volts or 220 Volts, because if the answer is 220 Volts, the single-phase 127 Volt standard will be discarded immediately.

All of the following information is in compliance with the ND-5.1 (Distribution Standard) standard of the electricity concessionaire CEMIG in the state of Minas Gerais. The loads in the table below are all single-phase 127 Volt. These values ​​were taken from the average power table for residential and commercial devices, made available by CEMIG, this table can be used when the power of a home’s equipment is unknown, for example.

Table of equipment of the residence.

After performing the survey of the powers of each equipment of the installation, it is necessary to  convert the powers of the equipment from Watts (W) to Kw (Kilowatt), to perform this conversion we need to divide the power of each equipment by a thousand, after that add up all the powers given in Kw, as we can see in the image below:

Conversion of equipment powers.

After all the calculations we arrived at the total value of the power (6.67 Kw) of the residence, with this value we should consult the information and tables of the concessionaires responsible for the distribution of electricity in your region, to obtain the information necessary to carry out the installation. of the input standard with, for example, electrical current value of the input standard circuit breaker, type of supply, conductor section and other information.

As our example was carried out in accordance with CEMIG’s ND-5.1 standard, we can find this information in table 1 (dimensioning for urban or rural consumer units served by three-phase secondary distribution networks (127 / 220v)). Below this table you will find the necessary information for the correct assembly in the input pattern.