Engine Installation Requirements According to European Directives
1. Purpose and Scope
This instruction defines engine installation requirements using portable professional tools receptors. All installations must meet the requirements of applicable European Directives as provided in Article 6 of the Low Voltage Electrotechnical Regulations.
2. General Installation Conditions
Engine installations must comply with UNE 20,460 and the specifications of the installation location. Engines must be installed to prevent accidents from contact with moving parts. They should not contact combustible materials and must be positioned to prevent ignition.
3. Interconnections
Minimum conductor cross-sections to prevent overheating:
3.1. Single Motor
Conductors feeding a single motor must be designed for 125% of the full load current. For wound rotor motors, conductors connecting the rotor to the starter must also be sized for 125% of the rotor’s full load current. For intermittent service motors, conductors can have a lower section based on continuous operating time, but never less than 85% of the rotor’s full load current.
3.2. Multiple Motors
Conductors feeding multiple motors must be designed for at least the sum of 125% of the most powerful motor’s full load current plus the full load current of all other motors.
3.3. Combined Loading
Conductors feeding motors and other loads must be sized for the total current required by all loads, with the motor load calculated as indicated above.
4. Overcurrent Protection
Engines must be protected against short circuits and overloads at all stages. Overload protection for three-phase motors must cover the risk of voltage loss in one phase. For star-delta starters, ensure protection for both star and delta connections. Protective devices must be appropriate for the motor and its operating conditions, following the manufacturer’s instructions.
5. Voltage Drop Protection
Engines must be protected against voltage interruption by a device that automatically shuts off power if spontaneous restarting after voltage restoration could cause accidents or damage, according to UNE 20,460-4-45. This device can be part of the overload or starting protection and can protect multiple motors if: a) the motors are in the same location and total power consumption is under 10 kW, or b) each motor in a separate location has automatic starting after a voltage drop. If a motor starts automatically under predefined conditions, voltage drop protection isn’t required, but spontaneous restarting must not cause accidents. If the motor limits starting current, automatic restart devices must return to their initial position after a voltage drop and stop the motor.
6. Starting Overcurrent
Engines must have limited starting current to prevent detrimental effects on the plant or disturbances to other loads. For public distribution networks, the distributor’s agreement is required for: high-inertia motors; slow-loading starters; frequently repeated starts; braking motors; and motors with reversing gears. Generally, motors over 0.75 kW must have starting resistors or equivalent devices to limit the ratio between starting current and normal full load current, as per the motor’s nameplate and the following table (table not provided in original text). For lifting equipment, the normal full load current is considered the current needed to lift loads at normal operating speed after starting, multiplied by 1.3. However, companies may waive these limitations if starting currents don’t disturb their distribution networks.
7. Rheostat Installation and Heating
Starting and speed control resistors must be at least five centimeters from walls. They must be positioned to prevent damage from heat or dust accumulation, both normally and during failures. They must not ignite building materials or other combustible objects. If this isn’t possible, combustible materials must have fireproof coating. Resistors must be isolated from the plant by omnipolar disconnects, which can be the main switches.
8. Portable Tools
Portable tools used in construction, quarries, and generally outdoors should be Class II or Class III. Class I tools can be used if fed through separate transformer circuits. For work in damp or hazardous locations (e.g., concrete work, inside boilers, metal pipes), portable tools must be Class III.