Electronics > Manufacturing & Assembly

Can we get away without using shielded cable?

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Faringdon:
We have  a plastic enclosed product comprising multiple PCBs...with a 20W offline SMPS supplying power as 12V rail. System Contains 3 other Buck converters. The 4 SMPS's are all on the same PCB. This PCB supplies power by cables to other PCBs, which dont have any SMPS's  on them. For the non-SMPS PCBs that are connected by wires between them, can we get away without shielded cable for these?

We wish to pass EN55032 (radiated emissions)

wraper:
If designed properly, it can pass radiated emissions without any shields and shielded cables. Look at phone chargers, they have similar power rating and I don't know any which are shielded. Also It would be great if you don't create tons of threads about the same thing with some variations.

Faringdon:

--- Quote ---If designed properly, it can pass radiated emissions without any shields and shielded cables. Look at phone chargers, they have similar power rating and I don't know any which are shielded.
--- End quote ---
Thanks, as you know, the phone charger plastic enclosure is likely to be foil lined...but if not....its quite likely to not pass radiated EMC regulations...

yes, but its interesting, ....Please add your thoughts to this....just imagine a company's product didnt comply with radiated EMC  regs....then the standards bodys would take samples of the company's product, do radiated EMC tests on them...and ban their product, right?....As you know, this never happens. A Radiated EMC test on an apparatus containing an offline SMPS takes ages to do  and costs utterly  shed loads of money...and can only be done in super-expensive  chambers which are pretty rare to find......the EMC antenna has to be moved all over the place to re-scan the product from different angles and elevations...then any failure peaks have to be re-scanned to see if they really are fails....takes ages  and ages. So no standards bodies have organised  radiated EMC testing for company products.
So many company's products simply dont comply with radiated EMC.....but what a small startup has to bear in mind, is that a big competitor may well sneak their product into a radiated EMC test...so that they can proove it fails....then they would put the small  startup out of business by using their highly payed lawyers to do this.
..But even that rarely happens....because if you bomb your enemies...then your enemies may bomb you too. So in fact, in radiated emissions, as well as many other  electrical standards areas....companys in a particular sector tend to have "amnestys", whereby neither criticises the radiated EMC (and other) failures of each other....and they live and let live. This often also happens with PFC (EN610000-3-2)...companys simply avoid using PFC on SMPS >75W...because all their competitors dont use it either....and neither criticises the other.
I believe we all know that the standards bodies (who answer ultimately to the governments), dont actually test samples of company products in order to see if they comply with radiated EMC regulations...as discussed...its just too expensive, and takes too long....there is a reliance on the goodwill of companys  to oversee it themselves. I mean, Western Governments have suffered such a  "dereliction of duty" such that the vast majority of the Western general  electronics sector has been outsourced to companies in the Far East.....leaving gaping holes in Western capability.....i'm sure we all realise that Governments that behave like that, are far from having the "upright-ness" towards  implementing measures to check and ensure products have the necessary  radiated EMC compliance.

Gyro:
You really are becoming a stuck record Treez. Hell, what do I mean becoming?  :palm:

https://www.eevblog.com/forum/renewable-energy/offline-isolated-smps-must-be-in-metal-enclosure-(to-pass-radiated-emissions)/msg3607222/#msg3607222

I count at least ten threads that you've started on this 'product'.

wraper:

--- Quote from: Faringdon on July 20, 2021, 06:39:23 pm ---
--- Quote ---If designed properly, it can pass radiated emissions without any shields and shielded cables. Look at phone chargers, they have similar power rating and I don't know any which are shielded.
--- End quote ---
Thanks, as you know, the phone charger plastic enclosure is likely to be foil lined...but if not....its quite likely to not pass radiated EMC regulations...

--- End quote ---
You just pulled it out of nowhere. They are not. https://www.chargerlab.com/apple-18w-usb-c-power-adapter-a1695-teardown-review-beautiful-inside-and-out/

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