SBS - The best value in QMS software

IEC 60601 Creepage and Clearance Requirements on PCB

A

AndrewJ

#1
I am developing a medical device that requires 60601 approvals which includes a device specific risk which requires mitigation by an electronic interlock circuit (requiring user intervention before the next action). Based on section 13 I understand that this interlock has to be single fault safe so I have two independent interlocks which prevent the harm from occurring.

Each interlock is constructed from analogue and digital logic at 3V and I am space constrained so I need to use small components and ICs with lead spacing less than 0.5mm. Section 13.2.1 of BS EN 60601-1:2006 + A12:2014 states that during the application of the single fault conditions the normal conditions identified in 8.1 a) also have to be applied. Where the spacing between two PCB tracks is less than 0.5mm they do not comply with the creepage distance requirements in table 16. Do I need to consider a short between tracks which don't comply with the creepage distance requirements as normal conditions when considering device specific hazards under single fault conditions? It is not clear whether a short in this situation has to be considered a normal condition when not being applied to electrical hazards.

I have just found that Annex A for subclause 13.1.1 states that the requirements for creepage and clearance are not intended to be required at the circuit board level (where the spacing cannot be compromised). This suggests that I do not have to consider shorting traces on a PCB as normal conditions but I cannot see how this is clearly referenced in the main standard. Based on this can two PCB traces separated by 0.3mm be exempt from having to be considered as shorted as normal conditions when applying single fault conditions?

Any help would be greatly appreciated.
 
Elsmar Forum Sponsor
#2
Hi Andrew and welcome to the forums.

The required creepage and clearance distances, as set out in section 8.9, are only required for insulations forming a MEANS OF PROTECTION. (Capitalisation indicates a defined term - see section 3). A MEANS OF PROTECTION (MOP) reduces the risk of electrical shock - it has a safety function.

For your insulation between PCB traces - that is functional insulation. There is no direct requirement in 60601 for minimum distances; you will need to rely on sound engineering judgement (I'm sure it's in a text book somewhere!). Factor in the 'pollution degree' ie the degradation over time due to contamination from dirt etc.
 

Loekje

Starting to get Involved
#3
I concur with PAD38.

We had a somewhat same situation where we actually did needed a MOP. This was resolved by applying conformal coating over parts of the traces and PCB. Mind though that it can be a real Pain in the Ass to proof that this coating is sufficient, in risk analysis and production control as well.

Lots of succes with your design,
Loek
 
#4
It is worth noting that if you use insulating compounds, such as conformal coating, you need then to apply the tests of section 8.9.3 to prove the suitability of your insulation.

This includes the thermal cycling test, which is both time consuming and very expensive to perform! And you can't really be sure of a positive outcome until you have done the test.
 

Marc

Hunkered Down for the Duration with a Mask on...
Staff member
Admin
#5
I can't speak to medical devices, but in aerospace when we did conformal coating or other "protection" we also had to do vibration, humidity and thermal shock testing. VERY expensive.
 
A

AndrewJ

#6
Thank you all for your replies. I am trying to avoid conformal coating exactly because of the cost and testing time.

Loekje, I would be really interested to understand the situation where you did need a MOP. Can you share any more information?
 
Thread starter Similar threads Forum Replies Date
B IEC 60601 - Creepage Distance - Relay that acts as a means of physical mechanical protection Process Maps, Process Mapping and Turtle Diagrams 0
T Clearance and Creepage according to Subclause 8.9.1 for MOPP IEC 60601-1 IEC 60601 - Medical Electrical Equipment Safety Standards Series 4
T IEC 60601-1 Conformal Coating not an acceptable mitigation for creepage and clearance IEC 60601 - Medical Electrical Equipment Safety Standards Series 2
M Is it normal / sufficient to have only the IEC 60601-1-2 test report without indicating IEC 60601-1? IEC 60601 - Medical Electrical Equipment Safety Standards Series 2
S IEC 60601-2-30 - Is it mandatory to claim alarms? IEC 60601 - Medical Electrical Equipment Safety Standards Series 1
Y Auditory alarm standard IEC 60601-1-8 Reliability Analysis - Predictions, Testing and Standards 0
R IEC 60601-1 - Power Supply Cords (Section 8.11.3.1) IEC 60601 - Medical Electrical Equipment Safety Standards Series 2
A Outsourcing IEC 60601-1 Ed 3.2 Testing IEC 60601 - Medical Electrical Equipment Safety Standards Series 0
R Complex IEC 60601-1 gap assessment IEC 60601 - Medical Electrical Equipment Safety Standards Series 0
D SINGLE FAULT CONDITION, short circuit and open circuit of any component (IEC 60601-1 3.1) IEC 60601 - Medical Electrical Equipment Safety Standards Series 9
H IEC 60601-1 ME equipment or ME system IEC 60601 - Medical Electrical Equipment Safety Standards Series 2
M How does IEC-60601-1 apply to a non-medical device in the patient vicinity? IEC 60601 - Medical Electrical Equipment Safety Standards Series 1
R IEC 60601-1 - 11.1.3 e) Test criteria - Temperature Measurements IEC 60601 - Medical Electrical Equipment Safety Standards Series 2
R IEC 60601-1 - Magnesium oxide used for the electrical insulation of heating elements IEC 60601 - Medical Electrical Equipment Safety Standards Series 3
M Is IEC 60601-1-2 required by FDA for all electronic medical devices? IEC 60601 - Medical Electrical Equipment Safety Standards Series 1
Z IEC 60601-2-25; Frequency response test Medical Device and FDA Regulations and Standards News 1
N IEC 60601-1-1 - Stress test, reference voltage IEC 60601 - Medical Electrical Equipment Safety Standards Series 2
R IEC 60601-1:2005+AMD1:2012+AMD2:2020 CSV IEC 60601 - Medical Electrical Equipment Safety Standards Series 1
T Single Fault Condition IEC 60601 Clause 8.7.1 shorting Cr/Cl in Patient Applied Part IEC 60601 - Medical Electrical Equipment Safety Standards Series 7
M What to Expect from Next IEC 60601-1 and IEC 60601-1-2 Amendments? IEC 60601 - Medical Electrical Equipment Safety Standards Series 7
D IEC 60601-1 - Service life testing IEC 60601 - Medical Electrical Equipment Safety Standards Series 8
R Hand transmitted vibration 9.6.3 of IEC 60601-1 IEC 60601 - Medical Electrical Equipment Safety Standards Series 4
A IEC 60601 11.2.2.1 Risk of Fire in an Oxygen Rich Environment, Source of Ignition IEC 60601 - Medical Electrical Equipment Safety Standards Series 0
E PEMS Hazards - IEC 60601 Clause 14.6 - Internal data use - Pressure sensor IEC 60601 - Medical Electrical Equipment Safety Standards Series 3
W IEC 60601 - Essential performance c.2.34 IEC 60601 - Medical Electrical Equipment Safety Standards Series 2
B IEC 60601-2-43 - Clause 203.6.103 - Physical button? IEC 60601 - Medical Electrical Equipment Safety Standards Series 1
M IEC 60601-1 1988 - Device developed in 2012 with standard of 1988 IEC 60601 - Medical Electrical Equipment Safety Standards Series 2
A IEC 60601-1 Dielectric Strength test for battery operated devices IEC 60601 - Medical Electrical Equipment Safety Standards Series 3
E IEC 60601-1 - Unearthed Medical Device Metal Parts IEC 60601 - Medical Electrical Equipment Safety Standards Series 1
JoCam Failure to test Class I medical device to IEC 60601-1-11 IEC 60601 - Medical Electrical Equipment Safety Standards Series 2
R IEC 60601-1 - Different methods of achievement of the isolation IEC 60601 - Medical Electrical Equipment Safety Standards Series 1
K What is mean by Oxygen Rich Environment as per the IEC 60601-1 clause no 11.2.2 IEC 60601 - Medical Electrical Equipment Safety Standards Series 5
K Dielectric strength test as per IEC 60601-1 -Infant incubator IEC 60601 - Medical Electrical Equipment Safety Standards Series 2
A Unused SIP/SOPs - IEC 60601-1 and IEC 60601-1-2 IEC 60601 - Medical Electrical Equipment Safety Standards Series 1
K Proper document of SMPS used in infant warmer for IEC 60601-1 testing IEC 60601 - Medical Electrical Equipment Safety Standards Series 1
K Sequence of testing in IEC 60601-1 IEC 60601 - Medical Electrical Equipment Safety Standards Series 2
B IEC 60601-2-10 - Accuracy of Pulse Parameters - Required Measurement Uncertainty IEC 60601 - Medical Electrical Equipment Safety Standards Series 3
B Has anyone done an IEC 60601-1 gap analysis to IEC 60335? Medical Device and FDA Regulations and Standards News 4
K Question on whether IEC 60601-2-62 standard is applied IEC 60601 - Medical Electrical Equipment Safety Standards Series 4
DitchDigger IEC 60601-1 subclause 5.1 - Adequate evaluation in lieu of testing IEC 60601 - Medical Electrical Equipment Safety Standards Series 2
B IEC 60601 Cl. 8.4.3 - ME EQUIPMENT intended to be connected to a power source by a plug / Plug discharge IEC 60601 - Medical Electrical Equipment Safety Standards Series 3
B Transformer Requirements - IEC 60601-1 vs. IEC 61558-2-15 IEC 60601 - Medical Electrical Equipment Safety Standards Series 0
A IEC 60601-1 and IEC 60601-2-2 IEC 60601 - Medical Electrical Equipment Safety Standards Series 3
M IEC 60601-1-2 EMC Tables IEC 60601 - Medical Electrical Equipment Safety Standards Series 6
T Iec 60601 Impedance and current-carrying capability IEC 60601 - Medical Electrical Equipment Safety Standards Series 1
A Bookmarking my security protected IEC 60601-1 .pdf file IEC 60601 - Medical Electrical Equipment Safety Standards Series 16
G Is impact test according to IEC 60601-1 applicable for HAND-HELD equipment if also classified as BODY-WORN? IEC 60601 - Medical Electrical Equipment Safety Standards Series 1
shimonv IEC 60601-1 Essential Performance - Is the signal accuracy specification an essential requirement? IEC 60601 - Medical Electrical Equipment Safety Standards Series 4
E ECG device without ECG REPORTS - IEC 60601-2-25: 2011 IEC 60601 - Medical Electrical Equipment Safety Standards Series 1
C IEC 60601-1-8, difference between table 4 and annex D IEC 60601 - Medical Electrical Equipment Safety Standards Series 2

Similar threads

Top Bottom