The main applicable items of the reference standards for the work performed by Blusafe are listed below:
5.1 NR-10 – Safety in Electrical Installations and Services
10.2.8 – COLLETIVE PROTECTIVE MEASURES
10.2.8.3 The grounding of electrical installations shall be implemented in accordance with the regulations by the competent bodies, in the absence of such regulations, existing International Standards shall be met.
10.3 – SAFETY IN DESIGN
10.3.4 The design shall define the configuration of the grounding scheme, the need for interconnection between neutral conductor and that of protection and the grounding of conductive parts that are not intended for the conduction of electricity
10.3.5 Whenever technically feasible and necessary, sectioning devices incorporating fixed equipotentialisation and grounding for the sectioned circuitshall be planned for.
10.3.6 Every design shall envisage conditions for the adoption of temporarygrounding.
5.2 ABNT NBR IEC 60204-1:2020
8.2 Protection circuits
8.2.1 Generalities
The protection circuit consists of the interconnection of:
● terminal(s) PE (5.2);
● protection conductors (3.1.51) on the machine equipment, including sliding contacts when they are part of the circuit;
● structural conductive parts and exposed conductive parts of electrical equipment.
● structural conductive parts of the machine.
It is not necessary to connect exposed conductive parts to the protective bonding circuit when these parts are installed in such a way that they do not constitute a hazard, because:
— they may not be touched on large surfaces or held by hand, and they are small in size (less than 50 mm × 50 mm approximately);
or
— they are located so that any contact with live parts or a failure in the isolation is unlikely.
This applies to small parts such as screws, rivets and nameplates and to parts inside an enclosure regardless of size (eg coils of contactors or relays and mechanical parts of devices).
8.2.2 Protective conductors
Protective conductors must be identified.
Metallic enclosures or electrical equipment mounting frames or plates, connected to the protection circuit, may be used as protective conductors if meet the following three requirements:
● its electrical continuity must be ensured by suitable construction or connection to ensure protection against mechanical, chemical or electrochemical deterioration;
● must comply with the requirements of IEC 60364-5-54:2011, 543.1;
● shall allow the connection of other protective conductors at each predetermined tapping point.
The following parts of the machine and its electrical equipment must be connected to the protection circuit, but cannot be used as protective conductors:
● structural conductive parts of the machine;
● metal ducts of flexible or rigid construction;
● metallic coatings or shields;
● metallic tubes that contain flammable materials such as gases, liquids, dust;
● flexible or malleable metallic conduits;
● constructive parts subject to mechanical stress in normal service;
● flexible metal parts, cable holders, cable trays and cable trays.
8.2.3 Protection circuit continuity
When a part is removed for any reason (eg routine maintenance), the protection circuit for the remaining parts cannot be interrupted.
Connection and connection points must be designed so that their current carrying capacity is not impaired by mechanical, chemical or electrochemical influences. When aluminum or aluminum alloy housings and conductors are used, special attention should be paid to the possibility of electrolytic corrosion.
8.2.4 Protective conductor connection points
All protective conductors must be terminated in accordance with 13.1.1. The protective conductor connection points are not intended, for example, to secure devices or parts.
Each protective conductor connection point must be identified or labeled using the IEC 60417-5019:2006-08 symbol, as illustrated in Figure 5;
figure 5 – IEC 60417-5019 symbol
8.2.5 Mobile machines
On mobile machinery with on-board power supplies, the protective conductors, the structural conductive parts of electrical equipment, and the external conductive parts that form the structure of the machine must all be connected to a protective bonding terminal to provide protection against electrical shock.
13 Electrical wiring practices
13.1 connections and routes
13.1.1 General requirements
All connections, especially those of the protective link circuit, must be secured against accidental loosening.
The connection of two or more conductors to a terminal is permitted only in cases where the terminal is designed for this purpose. However, only a single protective conductor must be connected to a single terminal connection point.
Welded connections should only be permitted when terminals suitable for soldering are provided.
Terminals on terminal blocks must be properly marked or labeled to match the identification used in the diagrams.
13.2 Conductors identification
13.2.2 Protective conductors/protective bonding conductors
protective conductors/protective bonding conductors must be readily distinguishable from other conductors by shape, location, marking or color. When identification is by color only, the bicolor combination of GREEN AND YELLOW must be used along the entire length of the conductor. This color identification is strictly reserved for protective conductors/protective bonding conductors.
For insulated conductors, the bicolor combination of GREEN AND YELLOW shall be such that on any 15 mm length, one of the colors covers at least 30% and not more than 70% of the surface of the conductor, with the other color covering the remainder of the surface.
When the protective conductor(s) can be easily identified by its shape, position or construction (e.g. a stranded conductor, uninsulated stranded conductor), or where the insulated conductor is not readily accessible or is part of a multi-core cable, color coding along its entire length is not required. However, where the conductor is not clearly visible along its entire length, the accessible ends or locations must be clearly identified.
5.3 ABNT NBR-5410 – electrical installation
6.4 Grounding and Equipotentialization
6.4.1 Grounding
6.4.1.1 Grounding electrodes
6.4.1.1.1 Every building must have a grounding infrastructure called “Grounding electrode”, the following options being allowed:
a) (preferably) use of the foundations’ concrete reinforcements (see 6.4.1.1.9); or
b) use of specially designed metal tapes, bars or cables immersed in the concrete of the foundations (see 6.4.1.1.10); or
c) use of buried metal meshes, at the level of the foundations, covering the building area and complemented, when necessary, by vertical rods and/or cables arranged radially; or
d) use of a buried metallic ring surrounding the perimeter of the building, at least, and complemented, when necessary, by vertical rods and/or cables arranged radially.
6.4.1.1.2 The grounding infrastructure provided for in 6.4.1.1.1 must be designed in such a way that:
a) be reliable and meet people’s safety requirements;
b) can conduct fault currents to earth without risk of thermal, thermomechanical and electromechanical damage, or electric shock caused by such currents;
c) when applicable, it also meets the functional requirements of the installation.
6.4.1.1.3 As the options for grounding electrodes indicated in 6.4.1.1.1 are also recognized by ABNT NBR 5419, they can and must be used together by the lightning protection system (LPS) of the building, under the conditions specified in that standard.
6.4.1.1.4 The use of metallic water pipes or other utilities as a grounding electrode is not allowed, which does not exclude the equipotentialization measures prescribed in 6.4.2.
6.4.1.1.5 The grounding infrastructure required in 6.4.1.1.1 must be accessible at least next to each entry point for conductors and utilities and at other points that are necessary for the equipotentialization mentioned in 6.4.2.
6.4.2 Equipotentialization
6.4.2.1 Main equipotentialization
6.4.2.1.1 In each building, a main equipotentialization must be carried out, bringing together the following elements:
a) the reinforced concrete reinforcements and other metallic structures of the building;
b) metal pipes for water, fuel gas, sewage, air-conditioning systems, industrial gases, compressed air, steam, etc., as well as the metallic structural elements associated with them;
c) the metallic conduits of the power and signal lines that enter and/or leave the building;
d) the shields, frames, coverings in metal sheets of cables of the power and signal lines that enter and/or leave the building;
e) the protective conductors of the power and signal lines that enter or leave the building;
f) the interconnection conductors from other grounding electrodes that may exist or are planned in the surroundings of the building;
g) the interconnection conductors from the grounding electrodes of neighboring buildings, in cases where this interconnection is necessary or recommended;
h) the neutral conductor of the electrical supply, unless it does not exist or if the building has to be supplied, for any reason, in a TT or IT scheme;
i) the main protective conductor(s) of the electrical installation (internally) of the building.
6.4.2.2 Supplementary Equipotentializations (Local Equipotentializations)
The performance of supplementary equipotentials (local equipotentials) may be necessary for reasons of protection against shocks, as foreseen in 5.1.2.2, or for functional reasons, including prevention against electromagnetic disturbances, as foreseen in 5.4.3.5. 6.4.2.2.1 Supplementary equipotential for protection against electric shocks.
Cases in which local equipotentials are required or recommended for protection against shocks are dealt with in 5.1.3.1 and in section 9.
6.4.3.3 Electrical continuity of protective conductors
6.4.3.3.1 Protective conductors must be adequately protected against mechanical damage, chemical or electrochemical deterioration, as well as electrodynamic and thermodynamic stresses.