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Overview of Low Voltage Electrical Safety Standards For Healthcare Facilities Presented by Ir. K.T. Lim 1
Overview of
Low Voltage Electrical Safety Standards
For
Healthcare Facilities
Presented by
Ir. K.T. Lim
1
Objectives
Benefits of standardizations.
Electrical Safety Standards and Electrical
Standards
Regulatory Framework
Types of Standards
Identifying Relevant Standards
Type and Routine Test
Dielectric, Insulation and Earth Bond Test
2
Benefits of Standardization
Economics – Suppliers and manufacturers
o Free movement of goods and services.
o Increase productivity.
o Support innovation.
o Create differentiation in competitive market – place.
Economics – Consumers
o Alternative sources and options.
o Lower costs and better performances.
o Better availability and interchangeability.
o Sound and tested engineering information – IEEE, ANSI.
3
Benefits of Standardization
Quality
o Minimum performance, functional and safety
specifications.
o Unambiguous and standardized test methods are
established.
o Independent test laboratory certification.
4
Benefits of Standardization
Computer Servers Installed Worldwide
5
Benefits of Standardization
Benefits of Standardizing Computer Servers
6
Low Voltage (LV) Electrical Safety Standards
Electrical products and systems are governed by one of the
most comprehensive standards – MS, IEC, NEC, IEEE, UL,
etc. because electrical hazards are usually not detectable by
human being and can be fatal.
LV electrical safety standards provide minimum requirements
and/or specifications and associated test methods for electrical
products and/or systems to achieve an acceptable level of life
–cycle safety and performance to user.
o What – All standards
o How and why – IEEE, NFPA
What is electrical safety ?
Safe to human being, pets and livestock,
and environment only
from electrical or secondary hazards.7
LV Electrical Standards
The major considerations for an LV electrical
standards.
o Ensure safety of users – reduce hazards to acceptable level
o Ensure safety of producer – reduce hazards to acceptable
level
o Minimize the life – cycle cost of operating the product or
services,
o Minimize the cost of manufacturing and delivery the
product or delivering the services.
All these above major considerations are intrinsic in
all LV electrical standards. Thus, discussing electrical
safety standards basically is discussing electrical
standards.
8
Regulatory Framework (Malaysia)
Department of
Occupational Safety
and Health (DOSH)
Energy Commission
Act 514, Act 139 & Act 302 Act 447
Regulatory/Statutory
Body
Constitution of
Malaysia
(Acts of Parliament)
Regulations
& Orders
Delegated Legislation or
Statutory Instruments
ICOPS, ContractsIndustrial Code of
Practices (ICOPS)
Administrative
OrdersCirculars, Notices
GMP, Standards, Guidelines, SOP, etcNon – Mandatory
Instruments
Man
dato
ry S
tan
dard
s
Mandatory
Voluntary
9
Regulatory Framework – Acts (Ordinances)
Department of Occupational Safety and Health (DOSH):
o Act 514 – Occupational Safety And Health Act 1994
o Act 139 – Factories And Machinery Act 1967
o Act 302 – Petroleum Act (Safety Measures)
Energy Commission of Malaysia (EC):
o Act 447 – Electricity Supply Act 1990
The State of Sabah
o The provisions under Electricity Supply Act 1990 are used with minor
deviation, such as from September 2003 the Sabah Land Ordinance,
Section 30(1)(bb) is also being used for way - leave.
The State of Sarawak – State Regulatory Framework:
o The Electricity Ordinance- Chapter 50 (Revised 2002).
o The Electricity (Amendment) Ordinance, 2003 (Chapter A109).
o The Electricity Rules, 1999.
o The Electricity (State Grid Code) Rules, 2003.
10
Malaysia – Mandatory Standards
Circular – MS IEC 60038: 2006 – IEC standard voltages
o Energy Commission circular. (Unreferenced)
o Effective 1st January 2008
o LV nominal system voltages changes from 240/415 +5%,-10% to
230/400V +10% ,-6% with frequency remains at 50Hz + 1%.
Circular – Electrical installation of buildings.
o Energy Commission circular reference: ST(IP/KKE) 16/1(3)
o Effective 1st July 2008
o MS IEC 60364: 2003 – Electrical installation of buildings.
o MS 1936: 2006 – Electrical installations of building – Guide to MS
IEC 60364
o MS 1979: 2007 – Electrical Installation of Buildings – Code of Practice
Certification of approval by Energy Commission
o 13A socket outlet – MS 589: Part 2 (BS 1363: Part 2)
o MCB – MS IEC 60898 – 1/2
11
Four (4) Basic Types of Electrical Standards
1. Fundamental standards – Terminology, metrology,
symbols, product rationalization.
o IEC 60050 – International Electrotechnical Vocabulary (Electropedia)
2. Test and analysis standards – Test and analysis of the
measurements.
3. Product and service standards – Characteristics and
minimum requirements of a product or specifications for a
service or system.
4. Organization standards – Description of the function of a
company to the relations between her and the structure of the
activities (The management and the quality assurance,
maintenance, etc)
o MS 1722 – Malaysia standard on OSHA management systems
o ISO 9001 – Quality management systems – requirements
o ISO 13485 – Medical devices – Quality management systems –
Requirements for regulatory purposes. 12
Test and Analysis Standards
Product
Rotating electrical machines.
o MS IEC 60034 – 1 – Rotating electrical machines – Part 1: Rating and
performance
Low voltage cables.
o MS 2112 - 2 – Electrical cable and wire – polyvinyl chloride (PVC)
insulated cables of rated voltages up to and including 450/750 V – part 2:
Test.
System
Electrical installations of buildings
o MS IEC 60364 – Electrical installations of buildings (Initial inspection
and testing)
Electrical and instrumentation loops
o IEC 62382 – Electrical and instrumentation loop check.
13
Product and Services Standards
Product
Rotating electrical machines.
o MS IEC 60034 series.
Adjustable speed electrical power drive systems
o MS IEC 61800 series
Residual current device.
o MS IEC 61008 – Residual current operated circuit – breakers withoutintegral over – current protection for household and similar uses(RCCBs)
System
Electrical installations of buildings
o MS IEC 60364 – Electrical installations of buildings.
Protection against lightning.
o MS IEC 62305 – Protection against lightning
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Combined Test and Analysis/Product & Services Standards
Usually, the test and analysis standards and, product andservices standards are combined in one series.
o MS IEC 60364 – Electrical installations of buildings.
o MS IEC 60034 – Rotating electrical machines
Example – MS IEC 60034 – Rotating electrical machines
o Part 1: Rating and performance
o Part 2: Methods for determining losses and efficiency of rotatingelectrical machinery from tests (Excluding machines for tractionvehicles)
o Part 3: Specific requirements for cylindrical rotor synchronousmachines.
o Part 6: Methods of cooling (IC code).
o Part 8: Terminal markings and direction of rotation
o Part 9: Noise limits\
o Part 11: Thermal protection
o Part 12: Starting performance of single – speed 3 – phase cageinduction motors
15
IEC Standard/Report – Not Standalone
IEC standard/technical report intended to be used by technical
committees when drafting product standards and apply only if
they are incorporated or are referred to in the relevant
standards.
o Provides fundamental principles and requirements which are common
to electrical installations, systems and equipments or necessary for their
coordination,
o Not intended to be used as a standalone standard, for example, for
certification..
IEC 60775: General requirements for residual current operated
protective devices,
o IEC 61008
o IEC 60947 – 2
IEC 61140: Protection against electric shock – Common
aspects for installation and equipment
o IEC 60364 – Electrical installations for buildings.16
Organization Standards
Description of the function of a company to the relations
between her and the structure of the activities (The
management and the quality assurance, maintenance, etc)
o MS 1722 – Malaysia standard on OSHA management systems
Quality management systems - Requirements
o ISO 9001 – Quality management systems – requirements
o ISO 13485 – Medical devices – Quality management systems –
Requirements for regulatory purposes.
o ISO/TR 16969 – Particular requirements for the application of ISO
9001:2000 for automotive production and relevant service part
organizations management systems.
17
Comparison Between ISO 9001 and ISO 13485
ISO 9001 and ISO 13485 are not completely congruent.o Organizations whose quality management systems conform to ISO
13485 can not claim conformity to ISO 9001, unless their qualitymanagement system conform to all requirements of ISO 9001.
Main difference between ISO 13485 and ISO 9001
o ISO 13485 is customized from ISO 9001 for specific requirementsrelating to medical devices.
o Product specific
o .Regulatory
o Documentation
o Customer satisfaction
o Continual improvement
ISO/TR 14969:2004 – Quality management systems –Guidance on the application of ISO 13485:2003
AAMI – Guidance to ISO 13485
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Comparison Between ISO 9001 and ISO/TS 16949
Differences between ISO/TS 16949 and ISO 9001
o Process efficiencies
o Cost of poor quality
o Cleanliness of the premises
o Predictive maintenance
o Use of statistical tools and data, field failures, FEMA, control plans
o Review of engineering specifications & non – conformance reporting.
o Assignment of a customer representative
Organizations whose quality management systems conform to
ISO/TS 16949 can not claim conformity to ISO 9001, unless
their quality management system conform to all requirements
of ISO 9001.
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Identifying Relevant Standards
Product and system standards and their associated test and
analysis standard
o This is a very simple process because there is almost one series of
standards associated with each type of product and/or system.
o Example:
(Product) Rotating electrical machines.- MS IEC 60034 series
(Product) Adjustable speed electrical power drive systems – MS
IEC 61800 series
(System) Electrical installations of buildings – MS IEC 60364 series
(Sub – system) Electrical installation of buildings - Requirements
for special installations or locations – Medical locations – MS IEC
60364 – 7 – 710.
Organizations standards – easiest to identify
o LV electrical systems for buildings – ISO 9001
o Medical devices – ISO 13485
20
Frequently Cited Electrical Safety Standards
IEC 60335 – Household and similar electrical appliances –Safety
IEC 60065 – Audio, video and similar electronic apparatus –Safety Requirements
IEC 61010 – Safety requirements for equipment formeasurement, control and laboratory use
IEC 60950 – Safety of information technology equipment
IEC 60601 – Medical electrical equipment – Part 1: Generalrequirements for safety
IEC 60204 – Safety of machinery – Electrical equipment ofmachines – Part 1: General requirement.
IEC 61508 – Functional safety of electrical, electronic andprogrammable electronic safety – related systems.
IEC 62368 – Audio/video, information and communicationtechnology equipment – part 1: Safety requirements –combined IEC 60065 & IEC 60950
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Type Tests
Type test or design test
o Conformity test on one or more items or devices or system (equipment,machine, components, sub – assemblies, etc) to a certain design andrepresentative of the production, to show that the design meets certainspecifications or comply with the requirements of the standard concernedprior to production.
o Carry out by accredited test laboratory.
Type test is carried out for new product/system (If theproduct/system standard specifies type tests) prior to production, or
o For existing type – tested product/system, when there is “significant”design changes to type test conditions when implementing engineeringchange.
o A test is destructive.
o A test is too expensive, time consuming, not viable, etc to carry out asroutine or production test.
Qualification margin.
o Difference between a type test condition and its corresponding most severespecified operating conditions – The difference between productionconditions and the conditions used for type test..
o Qualification margin accounts for variations in production of equipmentand reasonable error in defining satisfactory performance.
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Qualification Margin
Example of qualification margin – Temperature rise
Time
Tem
per
ature
Ris
e
Type Test Profile
Production Unit Profile
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Type Tests – LV Switchboard
1. Temperature rise – Verification of temperature rise limits.
2. Dielectric properties – Verification of dielectric properties.
3. Short–circuit withstand strength – Verification of the
short–circuit withstand strength.
4. Short – circuit withstand strength of the protective circuit
– Verification of the short – circuit withstand strength of the
protective circuit.
5. Clearance and creepage – Verification of the clearance and
creepage distance
6. Mechanical operation – Verification of mechanical operation
7. Degree of protection (IP) – Verification of the degree of
protection,
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Accreditation, Calibration & Certification
Accreditation
An authoritative body which gives formal recognition that a
body, facility, or person is competent to carry out specific tasks.
Malaysian Qualification Agency – Malaysian
Qualification Act 2007 for higher education
Registration of Engineers Act – Professional Engineers
Electricity Act – Competent electricians, supervising
engineer.
Calibration – Required only when measurements are for
acceptance purpose.
Certification – CB, IEC Excb, etc
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Dielectric Strength Tests (Type & Routine Tests)
Also known as dielectric withstand test or hipot test used for
both type and routine tests.
o Type test – Apply after tests such as fault condition, humidity, and
vibration to determine whether any degradation has taken place.
Purpose.
o To determine the adequacy of electric insulation for the
normally occurring over – voltage transient.
o To detect possible defects such as inadequate creepage and
clearance distances introduced during the manufacturing.
Test voltage – Most safety standard uses 2U + 1000V – U is
the operating rms voltage or according to test standard.
Voltage ramping – Not more than ½ of the prescribed voltage
be applied, and then raised gradually over a period of 10
seconds to the full value or according to test standard and
maintained for 1 minute.26
Dielectric Strength Tests (Type & Routine Tests)
Test duration – According to test standard for type test
o According to the test standard for type test – IEC 60950 is 1 minute.
o For routine test, it is normally not practical to hipot test each item for 1
minute. The manufacturer normally conduct the test to a much shorter
time, such as a few seconds, but with higher voltages.
A typical rule of thumb is 110% to 120% of 2U+1000 for 1–2 s.
Current setting – Most hipot testers allow the user to set the
current limit.
o If the actual leakage current of the item is known, then the hipot test
current can be predicted.
o The best way to identify the trip level is to test some product samples
and establish an average hipot current.
DC test voltage
o The insulation under test is most stressed when the ac voltage is at its
peak. To use dc voltage, make sure the dc test voltage is _/2 x ac
voltage.
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Dielectric Strength Tests (Type & Routine Tests)
One of the advantage of an ac hipot test is that it can check
both voltage polarities, whereas a dc hipot test charges the
insulation in only one polarity.
A minor disadvantage of ac hipot test is that if the item under
test has large values of Y capacitors, the hipot tester can
indicate a failure.
o Most safety standards allow the user to disconnect the Y capacitors
prior to testing or alternatively, to use a dc hipot tester.
The test setup and procedures are identical for both ac and dc
hipot tests
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Hipot Test Setup
Type Test Profile
Production Unit Profile
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Insulation Resistance Tests (Routine Test)
Also known as a Meggar test.
Measure the total resistance between two points separated by
insulation.
Test voltage – typically 500V – 1000Vdc
o The current flow is very low for a good insulation. Thus this test is
useful for checking the quality of the insulation not only when an item
is first manufactured, but also over time as the item is used.
Test procedure
o The insulation under test is connected to the measuring instrument and
the test voltage is ramped up from zero to the final value
o Once the voltage reaches the final value, it is hold for typically 5
seconds before the resistance value is measured.
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Earth Bond Test (Routine Test)
Also known as earth continuity test.
Must be conducted on all Class I equipment or system.
Purpose – To ensure that all accessible conductive parts of theproduct that could become line in the event of a singleinsulation fault are connected securely to the final earth pointof the supply input.
Test procedure
o The earth bond circuit is subjected to a high ac or dc current (I) with alow test voltage (V) for a period of time (T)
o Measure the voltage drop (V) of the earth bond circuit under test
o The earth bond resistance (R) is calculated using Ohm’s Law
o IEC 60950
V < 12V
I = 1.5 x rated current or 25A, whichever is higher
T = 1 minute
R < 0.1 ohm
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