Presentation DSB Rey-An Moreno

8/17/2019 Presentation DSB Rey-An Moreno

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BY: REYNALDO A. MORENO


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• To gather and protect the control and protectivedevices together with electrical and mechanical

connections against external influences.• To inform the end-user on the state of his

installation.• To protect the switchboard user against the main

risk of accidents (direct contact protection,indirect contact protection and fire risk).

• To evolve with the activity

What is a switchboard used for ?


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The LV electrical switchboard has to be safe

and available

• It is a question of balance between:

–

the needs of safety and availability – the constraints of reliability and maintenability of

the installation.Safety

Maintenability

Reliability Availability


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Ingress protection of enclosures


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Enclosure types in relation to location

Table B1 Enclosure types in relation to location

Location Switchgear andtransformers

Engine and boilerrooms

Above the floor IP 22

Dry control rooms andswitchboard rooms

IP 21

Closed compartments for

fuel oil and lubrication oilseparators

IP 44

Deckhouses, forecastle spaces, steering gearcompartments and similar spaces

IP 22

Ballast pump rooms, columns below main deck and

pontoons and similar rooms below the load Line

IP 44

Open deck, keel ducts

Battery rooms, paint stores, or areas that may behazardous due to the cargo or processes onboard

IP 56

Dry accommodation spaces IP 20

Galleys, laundries and similar rooms IP 44


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Enclosure

• Enclosures shall be

resistant to weather,oil and chemicals

• shall be made ofespecially corrosionresistant material or

dimensioned with acertain corrosionallowance

• Plastics, Light metalalloys as i.e.aluminum shall beavoided as enclosurematerials

• Flame retardant


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Cable Entrances

Cable entrances into enclosures shall be from below or from the side(except for enclosure IP 20), in order to prevent ingress of water orother liquids.


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Environmental Requirements

Temperature

Humidity

Relative humidity up to 95%.


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Environmental Requirements

Harmonic distortion

• Total harmonic content not exceeding 8% of voltage root meansquare value

• No single harmonic being greater than 5% of voltage root meansquare value.


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Power Distribution System

• The most common IT-system• Limited earth fault current – depending on capacitance in the cabling system• Alarm in case of an earth fault• Ideal for emergency power and important consumers with need for continuous

operation

• To be used in UPS-systems

Isolated IT-system


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• The miniature circuit breaker with integrated earth fault tripping is

functioning very well in a fully insulated IT-system!

Isolated IT-system (230 V)


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• Earth fault current calculated to maximum 100 A

• Consumers will be tripped in case of an earth fault

Impedance earthed IT-system


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• Two voltage levels in one system!

• 400/230 V are the most common voltages

• Separate N- and PE-conductors

• Consumers will be tripped in case of an earth fault

• EMC Performance - Excellent

Directly earthed TN-S system


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Motor Control

Motor Rated 1kW or above:

• a multipole circuit breaker

• fused circuit breaker or contactor - Each circuit-breaker ratedmore than 16 A shall be of trip-free type

• overcurrent release

• if necessary combined with a controller for limiting the startingcurrent

• control circuits with undervoltage release (UVR) –

Undervoltage and closing coils, including contactor coils,shall allow closing of the switchgear and controlgear whenthe voltage and frequency are 85 to 110% of nominal value.The undervoltage protection shall release if the voltage isbelow 70% or absolutely below 35% of nominal voltage.


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Assemblies

Main and emergency switchboardsand other switchboards requiringoperation shall have handrails with aninsulating surface.

The upper limit of the scale of ampere-meters and kilowatt-meters shall be at

least 130% of the rated fullload of the circuit.


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Emergency Stop

Emergency stop will not be required for the following:

• Fans not capable of supplying outside air to the space suchas fans in HVAC temperature control units

• Fans for heating coils.

• ventilation fans for cabinets and switchboards.


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Emergency Stop

If required:

• no single failure will cause loss of duplicated essential or

important equipment.

• For duplicated equipment, shall be arranged as twoseparate circuits with separate cables. A common stopbutton with several contacts (separate for each consumer)

will be accepted.• The emergency stop signal shall act independently of any

software based control system for the same consumer.

• A computer based emergency stop systems shall beindependent from other computer based systems with

control functions for the same consumers

• Alarm for loss of power shall be provided for normally openemergency stop circuits


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Signal Classes

• Class 1 - Mains power lines, power circuits with ahigh di/dt, switch-mode converters, power regulation

• Class 2 - Relay contacts.• Class 3 - Digital circuits (HF switching).• Class 4 - Analogue input/output circuits (low-level

measurements, active sensor supply circuits)


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Cables Construction

Conductor minimum cross section

0.22 mm2 Data communication cables

0.5 mm2 60 V cables and 250 V control and instrumentation cablesand control and instrumentation switchboard wires

1.0 mm2 Power circuit switchboard wires

1.0 mm2 250 V and 0.6/1 kV power cables

• plain or metal-coated annealed copper•

low emission of smoke in case of a fire• Halogen free cables• Braid or armour of lead, bronze or copper shall

not be installed in contact with aluminium alloy

structures,• except in dry accommodation spaces.


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Insulating materials

Temperature classes for insulating materials

Material Temperature ° C

Polyvinyl chloride or (PVC) 70

Hard grade ethylene propylene rubber (HEPR) 90

Halogen free hard grade ethylene propylene rubber (HF HEPR) 90

Halogen free cross linked polyethylene (HF XLPE) 90

Cross linked polyethylene (XLPE) 90

Halogen free cross linked polyolefin (HF 85) 90

The insulation on switchboard wires shall be at least flame retardant


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Protective Sheaths


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Minimum average thickness of insulating walls for power cableswith rated voltage 0.6/1.0 kV

Minimum thickness of insulating walls


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Control and Instrumentation Cables Rated 150/250 V

Minimum thickness of insulating walls


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Routing of Cables

• Cables for control or monitoring circuits

below 50 V shall not be run in the samebunch or pipe as cables for circuits emittinga high degree of electromagneticdisturbance, unless means to avoidinterference has been provided.


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Routing of Cables

• Crossovers or installation of power cables

and control cables beside each other aregenerally not considered a problem if signalcable is screened.

• A distance of 50 mm between power and

unbraided or unscreened control cables ona cable tray is considered acceptable.


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Routing of Cables

• Screens around individual pairs for earthing for EMCpurposes in cables for control, electronic, communication

and instrumentation equipment, shall normally be earthedat one end only. Cables having both individual screen andcommon screen (or braiding) shall have these metalcoverings separated from each other at the “floating” end,when earthed at one end only.

• Spare cable conductors shall either be terminated orinsulated.


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Component Placement

• Power and low level apparatus shall be physically separated andcables segregation and distances between power and sensitivecables shall also be respected as shown on the figure:


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Power Circuits

Busbars - The shape, configuration and cross-section shall be such that thetemperature rise will not exceed 45°C at rated load.

The cross-section of busbars for neutral connection on an AC three-phase, four-wiresystem, and for equaliser connection on a DC system, shall be at least 50% of thecross-section for the corresponding phases (poles).

The maximum permissible load for copper busbars with ambient temperature 45°C

With x thickness(mm)

Maximum permissible loading [A] with 50/60 Hz

Painted (matt-black) Bare

Numbers of bars Numbers of bars

2 3 2 3

15 × 3 390 470 350 445

20 × 3 485 560 430 535

20 × 5 690 900 620 855

20 × 10 1145 1635 1020 1460

25 × 3 580 650 510 615

25 x 5 820 1040 725 985


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Screening of horizontally installed busbars

• Horizontally installed busbars and bare conductors orconnections shall be protected by screens, if they are placed

such that there could be a risk of anything falling down on them.


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Termination

All connections for current-carrying

parts and earthing connections shall befixed so that they cannot loosen byvibration.


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Conductor Ends (Termination)

• All conductor ends shall be provided with suitable pressuredsockets or ferrules, or cable lugs.


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Cables Bending Radius


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Protective Earthing and Bonding of Equipment

-Copper

-The connection to the equipment enclosure parts, which shall beearthed, shall be made by corrosion resistant screws or clamps

-All earthing connections of copper shall have sufficient cross-section to prevent the current density exceeding 150 A/mm2 at themaximum earth fault currents that can pass through them.

-The temperature class of power cables shall be at least 10°Cabove the ambient temperature


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Earthing Connections and Conductors

Minimum cross-section of Earthing conductors

Arrangement of earthconductor

Cross-section Q ofassociated currentcarrying conductor(one phase or pole)(mm2)

Minimum cross-section of earthconductor

2. Uninsulated earthconductor in cable for fixedinstallation, being laid underthe cable's lead sheath,armour or copper braid andin metal-to-metal contactwith this.

Q ≤ 2.5 1 mm2

2.5 < Q ≤ 6 1.5 mm2

6 < Q Not permitted

3. Separately installed earthconductor for fixedinstallation

Q < 2.5 Same as current-carrying conductorsubject to minimum 1.5 mm2 forstranded earthing connection or 2.5mm2 for unstranded earthingconnection


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Termination and Cable Entrances

• Electrical equipment that needs to be connected to protectiveearth shall be provided with suitable fixed terminal for connecting

a protective earth conductor. The terminal shall be identified by asymbol or legend for protective earthing (PE).


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Cabinet Cabling

• Each cabinet must beequipped with an earthing

bar or a ground referencemetal sheet

• All shielded cables andexternal protection circuitsmust be connected to thispoint.

• Anyone of the cabinet metalsheets or the DIN rail can beused as the groundreference.


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Cabinet Cabling

Hinged doors shall be connected tothe switchboard or enclosure by aseparate, flexible copper earthconductor.

E l


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Enclosure

• Each cabinet must beequipped with an

earthing bar or aground reference metalsheet

• All shielded cables andexternal protection

circuits must beconnected to this point.

• Anyone of the cabinetmetal sheets or the DINrail can be used as the

ground reference.

Arrangement of Earth Bus bar


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Arrangement of Earth Bus-bar

• IE Bar should be isolated from the panel

Arrangement of Earth Bus bar


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Arrangement of Earth Bus-bar

IEC 61892-6 (2007):4.1.3 quotes:“Earth bars, when provided, shall

be located in front of equipmentand junction boxes to allow foreasy access for usage, inspectionand maintenance. All earth barsand terminals shall be visible andpossible to be checked also after

termination of cables.”

Arrangement of Earth Bus bar for MCC


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Arrangement of Earth Bus-bar for MCC

Install the complete cable rightup to the level of the

actual starter, and terminate thebraiding and/or earthconductor to the vertical subearth bar at this level !


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Equipment Protective Earthing

Terminals for circuits with different system voltages shall be separated, andclearly marked with the system voltage.

Single Point Earthing


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Single Point Earthing

DNV-OS-D201 (2011): Ch.2 Sec.10

quotes:“Single point earthing ispermitted for final sub circuitsand in those installations (such asfor control or instrumentation)where it is required for technical

reasons..”

Earth Terminations


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Earth Terminations

IEC 61892-6 (2007):4.1.3 quotes:

“Separate connections shall beused for each individual earthconductor.”

E i P i E hi


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• Suitable star washers and conductor terminals shallbe used, so that a reliable contact is ensured.

E i P i E hi


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• The earthing of the cable itself may be carried out by fixing thecable to the hull constructions, or to parts that are welded or

riveted to the hull constructions (metal to metal without paint orcoating), by corrosion resistant clamps or metal clips.

C l di i diff t thi t


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Colour-coding in different earthing systems

According to DSB with reference from NORSOK standard Rev. 3 item 12.5.3

• Protective earth (PE) bus-bars are to be colour-coded green/yellow and/orwith the letters PE.

• Instrument earth (IE) bus-bars should be colour-coded green/yellow withadditional red marking and/or with the letters IE.

• Intrinsically safe earth (IS) bus-bars should be colour-coded green/yellowwith additional light blue marking and/or with the letters IS.

OR

M ki d N l t


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Marking and Nameplate

• All equipment shall be externally marked

• All equipment shall if necessary be marked to ensure correct use

• All marking shall be permanently fixed.• All equipment shall be fitted with a rating plate giving

information on make, type, current, voltage and power rating

• All terminals for connection of external instrumentation andcontrol cables shall be marked.

M ki d N l t


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• Labels bearing clear and indelible indications shall be so placedthat all components and all equipment can be easily identified.

M ki d N l t


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• Labels bearing clear and indelible indications shall be so placedthat all components and all equipment can be easily identified.

Clearance and Creepage Distances


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Clearance and Creepage Distances

Clearance Clearance is the shortest distance between two conductive parts measured through air.Creepage Creepage is the shortest distance between two conductive parts measured along a surface.

“Type tested assemblies” and “Partly type tested assemblies”


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Type tested assemblies and Partly type tested assemblies

a) Electrical low voltage assemblies constructed and tested in accordance withIEC 60092-302, item 7.1.2.101

(referring to IEC 61439-1) are accepted as long as the following conditionsare met:— minimum clearance distance shall be 8 mm, minimum creepage distanceshall be 16 mm— the assembly has been type tested with impulse voltage test in accordancewith IEC 61439-1

— maximum operating temperature of busbars shall be documented to beacceptable with respect to fixingmaterials and internal temperature by a full current type test— maximum temperature rise at termination points for external cables shallbe 60ºC — such assemblies shall not be installed in machinery space category “A”.


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HAZARDOUS AREAS


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HAZARDOUS AREAS

• Zone 0 – Area in which an explosive gas atmosphere is presentcontinuously or for long periods.

– Certified safe for Intrinsic safety Ex-ia

• Zone 1 – Area in which an explosive gas atmosphere is likely tooccur in normal operation.

• Zone 2 – Area in which an explosive gas atmosphere is not likelyto occur in normal operation and, if it does occur, islikely to do so infrequently and will exist for a shortperiod only.

– certified safe for Zone 1 and Zone 2 application.

—Ex-n standard

—Minimum of IP45

Ex Protection According to Zones


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Ex Protection According to Zones

Zone 2 Zone 1 Zone 0

Ex d (flameproof) Yes Yes No

Ex e (increased safety) Yes Yes No

Ex i (intrinsic safe) Yes Yes Yes

Ex p (pressurised) Yes Yes No

Ex n Yes No No

Ex s (special protection) Yes Yes Yes

Ex m (moulded) Yes Yes No

Ex q Yes Yes No

Ex o Yes Yes No

HAZARDOUS AREAS


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HAZARDOUS AREAS

• Ex-e motors (increased safety)

– Overload or thermal protection

Frequency Converter– Ex-e and Ex-d motors driven by a Power converter is not accepted

• Ex-n motors driven by Frequency Converter needs a conformitydeclaration

– minimum IP44 degree

• Ex-p equipment

– Automatic shutdown and or isolation of equipment inside enclosures willbe required

HAZARDOUS AREAS


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HAZARDOUS AREAS

• Ex-d Explosion proof (flameproof) enclosure

– The part which can ignite an explosive atmosphere are placed in anenclosure which can withstand the pressure caused by an internal explosionand prevents the transmission of the explosion to the explosive atmospheresurrounding the enclosure.

• Exd enclosure - Should only be used forarcing (parts of) equipment. Exe junction

boxes are more convenient to use andmaintain!

HAZARDOUS AREAS


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HAZARDOUS AREAS

• Ex-i circuits

– All intrinsic safe circuits shall have a safety barrier in form of a zenerbarrier or galvanic isolation certified safe for the application in front of thecircuit part going into hazardous areas.

– A circuit in which no spark or any thermal effect produced is capable ofcausing ignition of a given explosive atmosphere

HAZARDOUS AREAS


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HAZARDOUS AREAS

• Ex-i circuits

– All intrinsic safe circuits shall have a safety barrier in form of a zenerbarrier or galvanic isolation certified safe for the application in front of thecircuit part going into hazardous areas.

• Exi barrier and circuit(s)

must be sufficiently separatedfrom other circuits

Corresponding Values for NEMA-Type and IP-rating


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Corresponding Values for NEMA Type and IP rating

Cable types Cabling and Termination


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Cable types, Cabling and Termination

• All cables installed in hazardous areas shall have an outer non-metallicimpervious sheath.

• Power and signal cables shall have a metallic braiding or armourbetween conductors and the non-metallic impervious sheath in thefollowing zones and areas:

— zone 0

— zone 1


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The tests of standard IEC 60439-1


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The tests of standard IEC 60439 1

There are two type of tests:

• 7 type tests are performed by the manufacturer on one or severalconfigurations: – n°1 temperature rise limits – n°2 dielectric properties – n°3 short-circuit withstand – n°4 protective circuit effectiveness – n°5 clearances and creepage distances – n°6 mechanical operation – n°7 degree of protection.

• 3 routine tests are performed by the panelbuilder on each particularswitchboard: –

n°8 general inspection

– n°9 insulation/dielectric test – n°10 protection measures.

Better be Safe than Sorry


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Explosion and fire can cause severe damage…


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Presentation DSB Rey-An Moreno

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