Re: [PSES] Y-capacitor body material - considered to be insulating?

2024-03-11 Thread Boštjan Glavič 
There is a CTL decision DSH 738 about insulation of body of Y capacitor. If you 
are talking about round coated blue Y caps, for Y1 type coated enclosure can be 
considered as reinforced insulation except in an area near leg outlet. CTL 
considered that coating near leg can break during placement on PCB.

However TC40 says this is wrong and they promissed back in 2018 some new 
guidance. I am still missing that one.

I cannot open your drawing. Could you resend?

Best regards
Bostjan




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Od: Joe Randolph 
Poslano: ponedeljek, marec 11, 2024 7:15:45 PM
Za: EMC-PSTC@LISTSERV.IEEE.ORG 
Zadeva: Re: [PSES] Y-capacitor body material - considered to be insulating?

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I seem to recall that there are some specifications for the insulating coating 
in the IEC 60384-14 standard for Y1 caps, but I have not worked with that 
standard for a while.

I agree with John Woodgate that a quick fix might be to place a piece of 
insulating tape on the surface of the board in the area under the cap.  I have 
seen Kapton tape used quite often to convert a clearance problem into “distance 
through solid insulation.”

Another quick fix that I have seen (possibly for the same reason) is to slide a 
piece of heat-shrink tubing over the cap and then apply heat to shrink the 
tubing.  The shrinkage of the tubing at the top and bottom of the rounded cap 
does a nice job of retaining the tubing on the cap.

So, if there is a production schedule to be met, some form of added insulation 
can probably solve the immediate problem.

In the long run, it may be possible to change the board layout so that there 
are no surface traces under the cap.  Note that the construction requirements 
for implementing basic or reinforced insulation within a circuit board provide 
several easy-to-meet options.  This is because the circuit board can be treated 
as “solid insulation”.

Joe Randolph
Telecom Design Consultant
Randolph Telecom, Inc.
781-721-2848 (USA)
j...@randolph-telecom.com
http://www.randolph-telecom.com

From: John Woodgate [mailto:j...@woodjohn.uk]
Sent: Monday, March 11, 2024 1:36 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Y-capacitor body material - considered to be insulating?


I think you have to ask the manufacturer of the capacitors about the insulation 
quality of the coating, and also test what happens if the insulation does break 
down; the result might be 'safe' but destructive.  At that point, high-voltage 
spikes on the AC input have to be taken into account. It looks as though 
changing the PCB would be a simpler solution than trying to prove that it's 
already OK or than adding a piece of insulating material and checking that it 
is still there.
On 2024-03-11 17:13, James Pawson (U3C) wrote:
Hello Group,

We are assessing a system that uses class Y1 capacitors for EMC filtering. 
Because of space constraints, they are laid down horizontally on the PCB.

This is causing a problem (at least in my mind) where the capacitor body is now 
resting on top of the AC input trace. The side of the capacitor connected to PE 
is the side closest to the AC mains input trace.

[?jpg 
icon]y-cap-body-insulation-question.jpg

One of those pieces of received wisdom that has been passed down to me is that 
“the body of components is not considered to be insulating” for the purposes of 
assessing creepage and clearance.

Common sense says “danger danger Will Robinson” and to change the PCB and/or to 
add some insulating material, but some technical back up would be welcome.

All the best
James


James Pawson
Managing Director & EMC Problem Solver

Unit 3 Compliance Ltd
EMC : Environmental & Vibration : Electrical Safety : CE & UKCA : Consultancy

www.unit3compliance.co.uk | 
ja...@unit3compliance.co.uk
+44(0)1274 911747  |  +44(0)7811 139957
2 Wellington Business Park, New Lane, Bradford, BD4 8AL
Registered in England and Wales # 10574298

Office hours:
Every morning my full attention is on consultancy, testing, and troubleshooting 
activities for our customers’ projects. I’m available/contactable between 1300h 
to 1730h Mon/Tue/Thurs/Fri.
For inquiries, bookings, and testing updates please send us an email on 
he...@unit3compliance.co.uk or call 01274 
911747. Our lead times for testing and consultancy are typically 4-5 weeks.






This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail

Re: [PSES] Y-capacitor body material - considered to be insulating?

2024-03-11 Thread Joe Randolph 
I seem to recall that there are some specifications for the insulating coating 
in the IEC 60384-14 standard for Y1 caps, but I have not worked with that 
standard for a while.

 

I agree with John Woodgate that a quick fix might be to place a piece of 
insulating tape on the surface of the board in the area under the cap.  I have 
seen Kapton tape used quite often to convert a clearance problem into “distance 
through solid insulation.”

 

Another quick fix that I have seen (possibly for the same reason) is to slide a 
piece of heat-shrink tubing over the cap and then apply heat to shrink the 
tubing.  The shrinkage of the tubing at the top and bottom of the rounded cap 
does a nice job of retaining the tubing on the cap.

 

So, if there is a production schedule to be met, some form of added insulation 
can probably solve the immediate problem.

 

In the long run, it may be possible to change the board layout so that there 
are no surface traces under the cap.  Note that the construction requirements 
for implementing basic or reinforced insulation within a circuit board provide 
several easy-to-meet options.  This is because the circuit board can be treated 
as “solid insulation”.

 

Joe Randolph

Telecom Design Consultant

Randolph Telecom, Inc.

781-721-2848 (USA)

  j...@randolph-telecom.com

  http://www.randolph-telecom.com

 

From: John Woodgate [mailto:j...@woodjohn.uk] 
Sent: Monday, March 11, 2024 1:36 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Y-capacitor body material - considered to be insulating?

 

I think you have to ask the manufacturer of the capacitors about the insulation 
quality of the coating, and also test what happens if the insulation does break 
down; the result might be 'safe' but destructive.  At that point, high-voltage 
spikes on the AC input have to be taken into account. It looks as though 
changing the PCB would be a simpler solution than trying to prove that it's 
already OK or than adding a piece of insulating material and checking that it 
is still there.

On 2024-03-11 17:13, James Pawson (U3C) wrote:

Hello Group,

 

We are assessing a system that uses class Y1 capacitors for EMC filtering. 
Because of space constraints, they are laid down horizontally on the PCB.

 

This is causing a problem (at least in my mind) where the capacitor body is now 
resting on top of the AC input trace. The side of the capacitor connected to PE 
is the side closest to the AC mains input trace.

 

 

 y-cap-body-insulation-question.jpg

 

One of those pieces of received wisdom that has been passed down to me is that 
“the body of components is not considered to be insulating” for the purposes of 
assessing creepage and clearance. 

 

Common sense says “danger danger Will Robinson” and to change the PCB and/or to 
add some insulating material, but some technical back up would be welcome.

 

All the best

James

 

 

James Pawson

Managing Director & EMC Problem Solver

 

Unit 3 Compliance Ltd

EMC : Environmental & Vibration : Electrical Safety : CE & UKCA : Consultancy

 

  www.unit3compliance.co.uk |  
 ja...@unit3compliance.co.uk 

+44(0)1274 911747  |  +44(0)7811 139957

2 Wellington Business Park, New Lane, Bradford, BD4 8AL

Registered in England and Wales # 10574298

 

Office hours:

Every morning my full attention is on consultancy, testing, and troubleshooting 
activities for our customers’ projects. I’m available/contactable between 1300h 
to 1730h Mon/Tue/Thurs/Fri.

For inquiries, bookings, and testing updates please send us an email on 
he...@unit3compliance.co.uk   or call 01274 
911747. Our lead times for testing and consultancy are typically 4-5 weeks.

 

 

 

 


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To

Re: [PSES] Y-capacitor body material - considered to be insulating?

2024-03-11 Thread John Woodgate 
I think you have to ask the manufacturer of the capacitors about the 
insulation quality of the coating, and also test what happens if the 
insulation does break down; the result might be 'safe' but destructive.  
At that point, high-voltage spikes on the AC input have to be taken into 
account. It looks as though changing the PCB would be a simpler solution 
than trying to prove that it's already OK or than adding a piece of 
insulating material and checking that it is still there.


On 2024-03-11 17:13, James Pawson (U3C) wrote:


Hello Group,

We are assessing a system that uses class Y1 capacitors for EMC 
filtering. Because of space constraints, they are laid down 
horizontally on the PCB.


This is causing a problem (at least in my mind) where the capacitor 
body is now resting on top of the AC input trace. The side of the 
capacitor connected to PE is the side closest to the AC mains input trace.


​jpg icon y-cap-body-insulation-question.jpg 



One of those pieces of received wisdom that has been passed down to me 
is that “the body of components is not considered to be insulating” 
for the purposes of assessing creepage and clearance.


Common sense says “danger danger Will Robinson” and to change the PCB 
and/or to add some insulating material, but some technical back up 
would be welcome.


All the best

James

James Pawson

Managing Director & EMC Problem Solver

*Unit 3 Compliance Ltd*

*EMC : Environmental & Vibration : Electrical Safety : CE & UKCA : 
Consultancy*


www.unit3compliance.co.uk  | 
ja...@unit3compliance.co.uk 


+44(0)1274 911747  |  +44(0)7811 139957

2 Wellington Business Park, New Lane, Bradford, BD4 8AL

Registered in England and Wales # 10574298

/Office hours:/

/Every morning my full attention is on consultancy, testing, and 
troubleshooting activities for our customers’ projects. I’m 
available/contactable between 1300h to 1730h Mon/Tue/Thurs/Fri./


/For inquiries, bookings, and testing updates please send us an email 
on he...@unit3compliance.co.uk  or 
call 01274 911747. Our lead times for testing and consultancy are 
typically 4-5 weeks./




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[PSES] Y-capacitor body material - considered to be insulating?

2024-03-11 Thread James Pawson (U3C) 
Hello Group,

 

We are assessing a system that uses class Y1 capacitors for EMC filtering.
Because of space constraints, they are laid down horizontally on the PCB.

 

This is causing a problem (at least in my mind) where the capacitor body is
now resting on top of the AC input trace. The side of the capacitor
connected to PE is the side closest to the AC mains input trace.

 

 

y-cap-body-insulation-question.jpg

 

One of those pieces of received wisdom that has been passed down to me is
that "the body of components is not considered to be insulating" for the
purposes of assessing creepage and clearance. 

 

Common sense says "danger danger Will Robinson" and to change the PCB and/or
to add some insulating material, but some technical back up would be
welcome.

 

All the best

James

 

 

James Pawson

Managing Director & EMC Problem Solver

 

Unit 3 Compliance Ltd

EMC : Environmental & Vibration : Electrical Safety : CE & UKCA :
Consultancy

 

  www.unit3compliance.co.uk |
 ja...@unit3compliance.co.uk 

+44(0)1274 911747  |  +44(0)7811 139957

2 Wellington Business Park, New Lane, Bradford, BD4 8AL

Registered in England and Wales # 10574298

 

Office hours:

Every morning my full attention is on consultancy, testing, and
troubleshooting activities for our customers' projects. I'm
available/contactable between 1300h to 1730h Mon/Tue/Thurs/Fri.

For inquiries, bookings, and testing updates please send us an email on
 he...@unit3compliance.co.uk or call
01274 911747. Our lead times for testing and consultancy are typically 4-5
weeks.

 

 

 

 


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