Is this 4-layer PCB good for mains?

Rick C wrote:

> That's what I'm accustomed to as well, but I still don't understand your comment "Just give me 2 prepregs and call it a 4-layer board."

If there were copper foil inserted between those two prepregs, the board
would be a 6-layer one and priced accordingly. Not putting the foil
there would spare them a number of technological steps, but the board
would be equivalent to a 6-layer PCB with 2 internal layers etched off
completely, leaving 4 properly spaced layers for HV routing. But that's
not how they make 6-deckers, anyway.

Best regards, Piotr
 
jrwalliker@gmail.com wrote...
IEC 62368-1:2014 has the following:

G.13.5 (page 240)

Insulation between conductors on different surfaces
[ snip ]

shall either have a minimum thickness of 0.4mm
provided by a single layer or conform with one
of the specifications and pass the relevant
tests in Table G.14.

Table G.14 Insulation in printed boards ...
Click to expand...

Thanks John, an excellent good post. But sadly
the spec isn't really all that helpful. 0.4 mm is
insufficient, and the testing requirement means,
for most of us, that we'll use an exact item that
somebody else has thoroughly tested (quick HV tests
of one batch are not enough). Hah, I'd be looking
to use slots, and avoid any mains traces opposite
each other. Once the ac power has gotten past the
MOV / TVS stage, one can relax the rules a bit.


--
Thanks,
- Win
 
On 8/13/19 9:00 PM, Rick C wrote:
On Tuesday, August 13, 2019 at 7:21:16 PM UTC-4, Phil Hobbs wrote:
On 8/13/19 7:02 PM, Rick C wrote:
On Tuesday, August 13, 2019 at 6:16:50 PM UTC-4, Piotr Wyderski wrote:

According to their stackup specification, the outermost layers in
6-layer PCBs are separated by a prepreg, not core, so it would
effectively mean 4 layers with double prepreg. Technically exacty what I
want, but psychologically an overkill. Just give me 2 prepregs and call
it a 4-layer board. ;-)

Not following what you mean. A 6 layer stack up is two cores and three prepregs. The 4 layer board is one core with the outer most copper layers separated by prepreg. What's wrong with that? If you can use a 4 layer board, why would you even be considering a 6 layer board? What am I missing?


The four layer boards we use are two cores and one prepreg.

That's what I'm accustomed to as well, but I still don't understand your comment "Just give me 2 prepregs and call it a 4-layer board."

'T'weren't mine.
Click to expand...

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
 
On 8/14/19 9:03 AM, Winfield Hill wrote:
Phil Hobbs wrote...

The four layer boards we use are two cores and one prepreg.

Who do you get them from?
Click to expand...
IIRC that was PNC in New Jersey, whom we no longer use. I checked our
recent fave PCBway, and their 4-layers are foil-prepreg-core-prepreg-foil.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
 
Piotr Wyderski wrote:

Here is the default stackup 4-layer PCB offered by a Chinese manufacturer:

https://www.allpcb.com/4_layer_pcb.html

The stackup is drawn at the very top, the specification of the
thickneses is at the bottom. Whould it be OK to use it in a 3-phase
400V AC system if all the layers would carry the mains potential?
The core (layers 2 and 3) would suffice for sure, but how about the
internal to top/bottom layers? Can prepreg be trusted enough? And
even if so, can it lead to any EU/US regulations violation?

Best regards, Piotr
Click to expand...
Hello there,
I think Chinese manufacturers are still good!
 
You must log in or register to reply here.

Welcome to EDABoard.com

Sponsor

Back
Top