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This page is devoted to the dispaly of summarized versions of lengthy and complicated regulations, directives and technical standards. The idea is: a project engineer, project manager or safety/EMC personnel who need to get basic information about a standard or other requirement they are not familiar with should be able in a few minutes to get an idea of:
IEC950/UL1950/EN60950
Standard for safety - Information Technology Equipment
1. General requirements:
1.1 General construction shall be such that under conditions of normal use
and under likely fault conditions it protects against the risk of:
1.1.1 electric shock
1.1.2 fire (including smoke)
1.1.3 mechanical hazard
1.1.4 excessive energy
1.1.5 dangerous radiation
1.1.6 dangerous substances and gases (eg ozone in HV power supplies)
1.2 Information will be provided to the user such that he may avoid hazardous
conditions.
2. Main implementation issues:
2.1 In most cases where mains voltage is involved, certified\registered components
should be used. (e.g. line filters, transformers, wiring, mains\high power
connectors, lamp ballasts, power supplies)
2.2 Flammable (mainly plastic parts and PCB base) materials should be certified for
their use.
2.3 The area between the high voltage circuits and the low voltage will have to be
checked very carefully to verify if the low voltage may indeed be treated as
"SELV" (Safety Extra Low Voltage). This should be verified in purchasd power
supplies and designed into PCB's and other circuits.
3. Tools and facilities:
3.1 High voltage breakdown
3.2 leakage current
3.3 high current - voltage testing (over grounding connection)
3.4 oven for large plastic parts
3.5 flame testing for plastic
3.6 multi channel temp testing
3.7 Standard test finger for checking accessibility
4. Most common problems:
4.1 non compliant components (eg part has UL but no TUV)
4.2 temperature problems with overloaded transformers
4.3 reliability problems with interlock path (use of software as part of interlock is
problematic)
5. Formal requirements:
5.1 Need an NRTL rep for the US. Will require follow-up of a local rep of the NRTL (visit 2-4
times a year, mostly checking the components used)
5.2 No need for Euro rep (self declaration)
6. Covers ITE:
6.1 Information Technology Equipment - computers and peripherals and any other equipment
which is based on microprocessor and electrical in nature.
6.2 Environment is basicaly "office" or "home". Environments are defined with various pollution
levels.
IEC1010-1/UL3101/EN61010
Standard for safety - Electrical equipment for measurement, control and lab use
(general requirements)
1. General requirements:
1.1 General construction shall be such that under conditions of normal use
and under likely fault conditions (a situation of "single fault" is defined not to cause
safety hazard) it protects against the risk of:
1.1.1 electric shock (Voltages and body currents are defined for normal and sinle fault
situation. In general, the requirements are different from the 950. High frequency
current is regarded as burn hazard)
1.1.2 temperature limits and spread of fire
1.1.3 mechanical hazard,(including resistance to shock, vibration and impact. This standard
contains requirements for vibration, drop and impact different from the 950)
1.1.4 Resistance to moisture and liquids (uses the IP levels)
1.1.5 Resistance to heat
1.1.6 excessive energy
1.1.7 radiation (Ionizing radiation, UV, microwave, sonic and ultrasonic, lasers)
1.1.8 dangerous substances and gases (eg ozone in HV power supplies)
1.1.9 Explosion and implosion
1.2 Information will be provided to the user such that he may avoid hazardous
conditions (marking and documentation).
2. Main implementation issues:
2.1 In most cases where mains voltage is involved, certified\registered components
should be used. (e.g. line filters, transformers, wiring, mains\high power
connectors, lamp ballasts, power supplies)
2.2 Flammable (mainly plastic parts and PCB base) materials should be certified for
their use.
2.3 The area between the high voltage circuits and the low voltage will have to be
checked very carefully to verify if the low voltage may indeed be treated as
"SELV" (Safety Extra Low Voltage). This should be verified in purchasd power
supplies and designed into PCB's and other circuits.
2.4 In every case where normal components are used, a single failure must be shown not to
cause a safety hazard. In several cases, "High Integrity Components" must be used. These
would probably be the agency certified components.
3. Tools and facilities:
3.1 High voltage breakdown
3.2 leakage current(the numbers are different than the 950, special circuits are defined for
simulating the "body current")
3.3 high current - ground continuity (over grounding connection)
3.4 oven for large plastic parts
3.5 flame testing for plastic
3.6 multi channel temp testing
3.7 impact testing uses the IEC 817 impact hammer (and not the 950 steel ball)
3.8 Standard test finger and test pin for checking accessibility
4. Most common problems:
4.1 non compliant components (eg part has UL but no TUV)
4.2 temperature problems with overloaded transformers
4.3 reliability problems with interlock path (use of software as part of interlock is
problematic)
5. Formal requirements:
5.1 Need an NRTL rep for the US. Will require follow-up of a local rep of the NRTL (visit 2-4
times a year, mostly checking the components used)
5.2 No need for Euro rep (self declaration)
6. This standard is applicable to "lab equipment":
6.1 Electrical measurement and test equipment
6.2 Electrical control equipment
6.3 Electrical laboratory equipment
6.4 Environmental conditions: indoor, 5-40 degC, max humidity 80%,
mains supply : +-10% of nominal
IEC 601-1
Medical Electrical Equipment - General Requirements for Safety
1. General requirements:
1.1 Protection against electric shock hazard
1.2 Protection against mechanical hazards
1.3 Protection against radiation hazards
1.4 Protection against ignition of flammable anaesthetic hazard
1.5 Protection against temperature and fire hazard
1.6 Overflow and spillage and liquids
1.7 Pressure : explosion and implosion
1.8 Protection against human errors
1.9 Protection against ESD
1.10 Materials in contact with the patient's body
1.11 Mains power interruption
1.12 Accuracy and protection against hazardous output
1.13 Abnormal operation and fault conditions
1.14 Testing of environmental conditions
1.15 Constructional requirements
3. Tools and facilities:
3.1 Standard test finger and test pin for checking accessibility
3.2 Additional "test hook"
3.3 Test circuitd for measuring "patient current"
4. Most common problems:
4.1 leakage current requirements may be very dificult to comply with.
5. Formal requirements:
5.1 In the US these will be through the FDA. Currntly there is the old UL 544 standard, but
it looks like the 601 is going to replace it.
5.2 In the EC the 601 is under the MDD (medical device directive) and a notified body has
to be involved in the testing.
6. This is tha basic standard for medical devices, there are many specific standards which
add requirements (such as "electro surgical devices).
Links to other sites on the Web
Please let me know how useful this information is to you and what
you would expect to further ease your way in the regulations and
standards maze. If you would like specific standards summarized on
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DISCLAIMER: The texts supplied on this site are only a summary of the relavant standards. Please obtain and use the full documents to abide with laws and regulations.
© 1996 mvaldman@netvision.net.il
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