Table of Contents

  1. General
  2. Standards
  3. Applicable Voltages
  4. Location of the Power Switching Devices
  5. Design Requirements
  6. Documents and Drawings
  7. Testing and Inspection
  8. Information to be Produced in Tender
  9. Information to be Produced after Ordering
  10. Attachments

1. General

1.1 Scope

1.1.1 This specification governs the minimum requirements for the design, materials, construction, fabrication, performance, inspection and testing, erection at site and delivery of materials and equipment for the electrical facilities, which form an integral part of a mechanical package unit.

1.1.2 This specification forms part of the overall mechanical specification of the package unit and the general requirements for the package unit also apply to the electrical equipment.

1.1.3 The specific electrical requirements will be detailed on the Electrical Datasheet for Package Units (EDPU), Attachment 1, which forms an integral part of this specification.

1.1.4 Standard IEC electric motors to be supplied for the package, can be part of a frame agreement that Company has with a motor supplier. The name of the motor supplier is given in the attachment. The supplier of the package unit shall order the electric motors from this supplier. The only exception are non standard tailor made motors.

1.1.5 It is the supplier's responsibility to be, or to become, knowledgeable of the requirements of this specification and any referenced specifications. Any subsequent changes or alterations to the equipment to make it comply with the specified requirements shall be made at the expense of the supplier.

1.2 Plant Site

The facilities will be constructed for and built at:

Plant ID :

Client :

Location :


1.3 Area Classification

1.3.1 In the data sheet (EDPU) is indicated if the package is located in a safe or a hazardous area. If the package is located in a hazardous area, the parameters for the materials are specified. See Attachment 1.

1.3.2 The construction of electrical equipment shall comply with the requirements of the relevant parts of IEC 79.

1.3.3 The relevant types of EEx protection to be applied can be found in the data sheet (EDPU).

1.3.4 Electrical materials used inside an enclosure, for instance an accessible noise hood.

The electrical materials inside the enclosure shall be limited to the smallest possible extent. The enclosure normally not being accessible other than for maintenance reasons.

If the enclosure is located in a Zone 2 area and adequate redundant forced ventilation is provided, the electrical equipment shall, in principle, be suitable for Zone 2.

Adequate ventilation is defined as follows:

100 % redundancy of the EEx-d fans;

· the fans properly interlocked and powered from a safe power supply source;

· the interlocking system to be suitable for auto restart upon return of the (emergency)power;

· the interlocking system to prevent a start of the main motor before the enclosure is adequately flushed with Zone 2 air.

In any case the construction of the enclosure and the types of the materials applied shall be subject to a review by purchaser.

1.3.5 For electrical apparatus suitable for Zone 1 and or Zone 2 ( for instance Ex "n", EEx "e", EEx "d" or EEx "p"), an approval certificate issued by the appropriate authority (e.g., PTB or BASEEFA) shall be provided.

1.4 CE marking

For plants in the EEU equipment shall be provided with the CE marking.

2. Standards

2.1 All electrical equipment, materials, components and installation shall comply with this specification, the requisition and the latest edition including amendments of the following rules and regulations:

· all applicable local rules and regulations of the country as stated in the requisition;

· requirements of the Power Supplier;

· referenced documents as stated in the requisition;

· all applicable IEC publications and/or other standards referred to in the data sheet (EDPU);

· Other standards may be considered by Contractor, provided they are based on the IEC recommendations, but written approval from Purchaser is required.

2.2 The supplier shall state on the data sheet (EDPU) the standards applicable to the equipment being offered.

3. Applicable Voltages

3.1 The applicable distribution voltages for the various services shall be as specified in the data sheet (EDPU).

3.2 The equipment, shall be suitable for operation on these voltage level(s) and frequency. Any transformer or other electrical device necessary to achieve the required voltage shall be provided by the supplier.

3.3 Supplier shall take into account that during switching, steep-fronted transient voltage waves may occur at the equipment terminals. Wave front durations between 0.2 s, with amplitudes of twice the nominal value of the line voltage, and 1 ms, with amplitudes of 5 times the nominal value of the line voltage, are produced.

3.4 During starting or reacceleration of a motor, either alone or in a group, the voltage at the motor terminals can be 85% of the rated equipment voltage.

3.5 Should the package require Uninterruptable Power Supply (UPS) power this shall be clearly stated by the supplier in the bid indicating the required power.

3.6 Any analog control signals entering the package or indication or control signals generated by the package shall be at the levels as specified in the data sheet (EDPU).

4. Location of the Power Switching Devices

4.1 Independent from the location of the power switching devices, the package unit supplier shall list on the data sheet the kW ratings of all equipment to be powered for the package unit. This includes: motors, control power, heaters, possible lighting etc.

4.2 If indicated "MCC" on the data sheet (EDPU), the power switching will be done in the MCC supplied by the Purchaser, located in a switchroom, remote from the package unit.

4.3 If indicated "Local Panel" on the data sheet (EDPU), the power switching will be done in the panel to be provided by the package unit supplier.

4.4 For package units with a local control panel, the motor control pushbuttons, indicating lamps, meters, etc. shall be supplied, installed and wired in the local panel by the supplier.

For package units without a local control panel, all motor controls other than the standard package mounted devices shall be provided by the Purchaser. The supplier shall clearly indicate on the drawings any items to be supplied by purchaser.

4.5 The supplier shall ensure that any equipment to be connected into the control circuit of the MCC is suitable for operation at the control voltage stated on the data sheet.

The control and interlocking and/or sequencing required shall be provided by the package unit supplier. The control and interlocking sequencing may be interlinked with purchasers DCS system.

In order to standardize the control, the required contacts and their properties are given in the data sheet (EDPU), same for mA, V and Amp signals.

4.6 Socket outlets and motors shall be provided with earthfault protection.

4.7 Should the switching of motors occur in the scope of the package unit, the motors shall be protected by means of gG knife type fuses, thermal overload protection and earthfault protection. Each motor circuit shall be provided with a fault make load break switch isolating the motor circuit from the incoming feeder power. The control shall be done using a contactor.

5. Design Requirements

5.1 General

5.1.1 The electrical equipment and their connections shall be designed and manufactured to facilitate easy operation, inspection, cleaning, maintenance and repair, and to ensure safety during such procedures.

5.1.2 All equipment shall be suitable for continuous operation.

5.1.3 The package unit shall be complete with all necessary service functions including any local requirements for lighting, heating and socket outlets. The lighting of the package unit shall be integrated in the lighting system of the plant, the package unit supplier shall adhere to the instructions of purchaser with regard to the lighting layout and types of materials to be used.

Area lighting will be provided by others as part of the overall installation.

5.1.4 A padlockable isolation switch, operable from outside the control cabinet, shall be provided for the incoming supply to the control cabinet. The switch shall be lockable in the "off" position.

It shall not be possible to open a cover or gain access to the interior unless the disconnector is in the "OFF" position. For 4 wire systems the neutral shall also be disconnected.

5.1.5 In order to maintain consistency of the electrical materials used in the plant. The materials used in the power and or control part of the package, shall be the same as the ones used in the plant. Purchaser shall specify the make and types of the equipment used in the plant.

As this concerns standard materials only, the package unit supplier shall adhere to this requirement. Examples are: Contactors, thermal relays, earthfault relays, control switches, junction boxes, lighting fixtures, control and power terminals etc.

Similar parts shall be interchangeable whenever possible.

Cables shall be according the types specified by the purchaser.

5.1.6 Gaskets shall be manufactured from neoprene, or a similar material approved by purchaser.

5.1.7 For package units in tropical areas, thermostat controlled space heaters and or suitable draining plugs shall be installed in the local control panel to prevent accumulation of condensate. The power supply for the heaters shall be derived from the main incoming power supply.

5.1.8 The covers on all equipment shall be designed for easy removal for inspection and maintenance, the components within the enclosure shall be readily accessible and the minimum degree of internal protection shall be IP 20.

5.1.9 Aluminum or aluminum alloy shall not be used for equipment enclosures unless approved in writing by the Purchaser. Where such materials are approved, they shall be epoxy coated.

5.1.10 For maintenance purposes and continuity of operations, each logical electrical function group in a local control panel shall be separately protected.

5.1.11 Adequate space shall be provided between the gland plate and the incoming/outgoing terminals, for control and power cabling a minimum of 200 mm shall be provided, for power cabling the minimum height shall additionally be determined by the type of cable to be applied and the cross section of the cabling and the space to terminate the cable.

5.1.12 Equipment such as indicating instruments, pushbuttons, etc. shall be flush mounted on the front of the enclosure.

5.1.13 The colors of the indicating lights and pushbuttons shall conform to the IEC standards.

5.1.14 Relay boxes and control cabinets shall be mounted on free-standing frames. Minimum free distance underneath the cable glands to be 60 cm.

5.1.15 All components shall be accessible from the front of the control cabinet.

5.1.16 All live parts of equipment and components located within the control cabinet shall be shielded to provide a degree of protection of at least IP 20 to prevent inadvertent contact or short circuit by personnel.

5.1.17 Shielding shall be of rigid transparent insulating material to enable identification of the screened components. Protection relays, which may cause tripping of the unit, shall not be mounted on the door.

5.1.18 A schematic diagram shall be installed inside the switch or relay box.

5.2 Degree of Protection

5.2.1 The degree of protection for materials located indoors or outdoors, shall be as specified in the data sheet (EDPU).

5.2.2 If indoor enclosures require ventilation, as with some air?cooled solid?state power controllers, the minimum degree of protection shall be IP 31 with the internal assemblies treated and proofed against humidity and dust accumulation. The supplier shall state in the bid the means by which this is achieved e.g. fully tropicalised.

5.3 Isolation/Control/Protection Facilities

5.3.1 All electric motors shall be provided with a padlockable control switch near the motor. This switch shall, in the off position, prevent the contactor to be energized, by short-circuiting the contactor (relay) coil.

5.3.2 For equipment which can endanger personnel safety padlockable local safety switches shall be provided to direct switching the power supply to the motor. As a minimum, the local safety requirements shall be met.

5.3.3 Local switches near the motor shall be of the rotary type.

5.3.4 Emergency stop pushbuttons shall be adequately shielded against in advert tripping. The emergency push-button shall be of the mushroom type with "a rotate to release" facility.

5.3.5 Motor thermal overload relays shall be installed in all phases and shall include protection against single phasing. The relay shall be of the temperature compensated type. For EEx?e motors the relay shall be of the time delayed type as required by IEC 79?7, para 4.7.

5.3.6 Trip indication shall be provided on the front of the control panels, a provision for a remote common alarm shall be included. (Contact to be of the Change Over type).

5.4 Separation of Control/Power Circuits

5.4.1 Basically the control and the power circuits of a packaged unit shall be physically separated. Logical control circuits shall be grouped together.

5.4.2 Terminals of circuits which operate at different voltages shall be physically separated (e.g. by means of separation barriers at terminal rows).

Separate terminal rows shall be provided for external control, alarm and/or measuring circuits.

5.4.3 For packaged units with the control cabinet located away from the main skid, the following shall apply:

a. control/measuring signals which originate on the skid of the packaged unit shall be wired to a central terminal box located on the skid.

b. control cables between the control switches of electric motors and the cabinet shall be terminated in a separate intermediate terminal box located on the skid.

c. all interconnecting cabling on the package unit shall be provided and be installed by the supplier of the package unit.

d. all interconnecting cabling between the intermediate terminal boxes and the supplier supplied control panel shall be provided and installed by purchaser.

e. all power cabling shall run directly to the terminals of the relevant equipment. The supplier of the package unit shall provide adequate conduits, trays or trunking on the assembly to run the power cable. The power cable will be provided and installed by purchaser.

5.5 Rating of Components

5.5.1 Isolation switches shall be of the manually operated air-break type and shall, as a minimum, comply with utilization category AC?22 or AC?23 depending on their application.

5.5.2 With reference to IEC-947-4 motor starters and contactors shall conform to the requirements of both uninterrupted duty and class 0.1 of intermittent duty with the rated operational current. The mechanical endurance level shall be at least one million no-load operating cycles.

5.5.3 Ammeters and voltmeters shall be accuracy class 1.5 according to IEC?51.

5.5.4 Basically all LV fuses shall be of the DIN knife type. Fuse holders shall have a degree of protection IP20. The fuse characteristics shall be in accordance with IEC 269, gG, the only exception are fuses protecting electronic circuits for this type of fuse the ultra rapid type.

5.5.5 Miniature circuit breakers shall only be applied in control circuits. The MCB shall be suitable for the occurring short circuit current.

5.6 Wiring

5.6.1 Control wiring shall be stranded copper, be black coloured PVC insulated and have a minimum cross section of 1.5 mm² inside cabinets and 2.5 mm² for all other applications. Wire ends to be provided with suitable compression type wire pins. The AC-voltage withstand level of the PVC-wiring shall be 2500 V.

5.6.2 For all control wires individual terminals shall be provided, two wires on or in one terminal are not permitted. Two wires are only allowed if these two wires are joined together into one wire pin.


The term terminal is used for a termination, a connection point and a terminal either of the block or the DIN rail row type.

5.6.3 Wiring between terminals shall be continuous and be without joints.

5.6.4 Wires shall not be mounted directly to metal, but shall be kept in position by means of insulated tubes, channels/ducts, cleats or plastic strips.

5.6.5 Control wiring shall be identified at both ends by means of ferrules of insulating material marked in accordance with the related wiring diagrams.

5.6.6 Terminals shall be of non-loosening construction, obviating the use of cable lugs, and be constructed in such a way that a direct contact between screw, bolt or nut and conductor is avoided.

An additional 20% spare terminals shall be provided for all but the main incoming power circuits.

5.6.7 All terminal blocks shall be of the DIN rail row mounting type.

5.6.8 Measuring circuit terminals shall be provided with the facility for connecting a test instrument without the need to loosen the conductor. Terminals for current measuring circuits shall have a short circuiting link.

5.7 Identification and Labeling

5.7.1 Each item of the electrical equipment included in the supplier's supply shall be identified in accordance with the Purchaser's tag numbers. The dimensions of the labels etc. shall be according to the data of the data sheet (EDPU).

5.7.2 The control cabinet and all its main components such as, but not limited to, switching devices, protection relays, instruments, instrument transformers, fuses and fuse holders shall be individually identified in accordance with the related schematic diagrams by means of permanent labels.

In addition, all components shall be marked with their ratings and all other essential data, following IEC-recommendations including the following minimum information:

· Manufacturer's name or trade mark and type designation.

· System characteristics; e.g., rated main and auxiliary operational voltages, frequency and number of phases.

· Rated current or rated power of all individual devices.

· Accuracy class and accuracy limit factor; e.g., for instruments and instrument transformers.

On withdrawable type units, identification labels shall be mounted on both the fixed and withdrawable parts.

5.7.3 Generally, identification labels shall be of the laminated plastic type having black engraved letters on a white background. For areas with an atmosphere aggressive to plastic, the labels shall be of stainless steel.

5.7.4 All labels shall be fixed using stainless steel screws or rivets. Adhesive shall not be used for this purpose.

5.7.5 Labels etc. on EEx certified material shall be installed by the supplier of the material, according the above instructions.

5.8 Cables and Terminations

5.8.1 For outdoor location: The cables shall enter the cabinet and the terminal boxes from below.

For indoor location: The cables shall enter the cabinet and the junction boxes from below, except if indicated differently in the data sheet (EDPU).

5.8.2 Cable entries, cable glands, cable clamping, earthing, supporting devices and terminals shall be provided by the supplier of the package unit. These shall be suitable to accept the type, size and number of cables specified in the data sheet (EDPU).

5.8.3 The cable glands to be provided shall be according the make and type as specified in the data sheet (EDPU). The entry threading shall be metric with a pitch of 1,5 mm.

For equipment standard supplied complete with plastic glands, such as EEx lighting fixtures, EEx lighting junction boxes and EEx RCU's, these glands and their possible Metric threading are acceptable.

5.8.4 For external cabling, individual terminals for each conductor shall be provided. Each terminal shall be suitable for the full cross section of the cable as specified.

5.9 Motors

5.9.1 All motors shall comply with the motor specification and the associated motor data sheet.

5.9.2 The required operation voltage for the motors depends on the motor rating and shall be as specified on the data sheet (EDPU).

5.9.3 Start current limitation can be imposed by purchaser depending on the size of the motor.

5.9.4 Reference is made to above regarding the supplier of the standard IEC motors.

5.10 Earthing

5.10.1 All electric motors, terminal boxes and cabinets to have connection points for the external earthing conductor. Two connection points shall be located at diagonally opposite corners of any skid associated with the package unit.

For the cabinets and the skid the connection points shall be a welded boss which has been drilled and tapped with an M10 thread.

5.10.2 All non?current carrying metal parts (e.g. motor frames, control panels, etc.) of the package unit shall be effectively connected to the main earth connection points. The supplier is responsible for the provision of all bonds and earth continuity conductors to ensure this effective connection

5.10.3 Stranded copper conductor having a green/yellow coloured sheath shall be used for earth bonding. The minimum size of earth bonding conductor for electrical enclosures shall be 25 mm² for LV motors and for MV motors 70 mm². Vessels and tanks etc. shall be bonded to earth using 25 mm² conductors

5.10.4 A copper earthing bar of 25 x 5 mm over the full length of the control panel shall be provided, with at least one hole for each entering cable. The connection shall be made with a bolt, washer and nut. Each cable earthing conductor shall be separately connected. Earthing bars in EEx junction boxes shall be supplier’s standard size.

5.11 Materials and Equipment

5.11.1 All materials and equipment for the installation shall be new and unused, be of first class quality and manufactured in compliance with relevant local or other recognized standards.

5.11.2 Prior to ordering main electrical equipment purchaser's approval shall be obtained for the basic design.

5.12 Electrolytic Corrosion

5.12.1 All materials shall be selected to prevent contact corrosion between dissimilar materials. All screws, bolts, washers and nuts on the electrical equipment shall be corrosion-resistant.

5.12.2 Combinations of dissimilar metals are permissible without the risk of corrosion where the contact potential difference is less than 50 mV. Isolating bushes, plates, etc. shall be installed where the potential difference exceeds 50 mV.

5.13 Cables

5.13.1 The cable types and design shall be according the ones specified in the EDPU. If lead sheathed cable is required, special attention shall be paid to the glands for sealing-off the lead sheath.

6. Documents and Drawings

Drawings and documentation shall be provided in the quantities and format in accordance with the requirements of the mechanical purchase order.

7. Testing and Inspection

7.1 The supplier shall submit for approval by the purchaser, a schedule of the proposed electrical tests, which will be carried out on the equipment in the works prior to shipment. These tests shall include as a minimum the following:

· Insulation resistance measurements of all items and wiring.

· High voltage withstand test.

· Mechanical and electrical operation of all functioning parts including relays, meters, solenoid valves, indicators, etc.

· Full functional check of control circuit operation.

· Full dimensional check of the equipment against the supplier's final certified drawings, including particular checks on the location and size of cable entries.

· Checks of cable termination facilities, equipment enclosures (i.e. weatherproof, flameproof, etc.) against the relevant specification and supplier’s certified drawings.

· Proof integrity of the earthling bonding.

7.2 Provision of suitable test equipment for electrical tests shall be the technical and financial responsibility of the supplier. Where considered appropriate, the supplier shall provide a suitable test panel in order to simulate the field devices e.g. contacts and indicating lamps.

8. Information to be Produced in Tender

8.1 A brief description of the electrical installation complete with the voltage(s) and installed and running load(s) in kVA and kW.

8.2 A list of material and equipment recommended, complete with manufacturer's reference numbers and dimensions of relay box, etc.

8.3 A typical electrical schematic diagram with cable and panel layouts.

8.4 A planning of all phases of the electrical installation, e.g. design, erection and testing.

8.5 A complete technical description.

9. Information to be Produced after Ordering

9.1 The supplier shall provide the electrical documentation as required in accordance with the purchaser's requirement.

9.2 Detailed information as preliminary produced in tender. Refer to 8.

9.3 Drawings showing additional civil provisions necessary for the electrical installation.

9.4 Summary of standards with which the materials and equipment are complying. Refer to 2.

9.5 Copies of certificates. Refer to 1.3.5.

9.6 A recommended spare parts list of the electrical installation.

9.7 Maintenance and service instructions of the electrical installation.

10. Attachments

1. Electrical Datasheet for Package Units (EDPU) – (3 sheets)