I am not capable of designing a ClassII product. I don't know all the regulations that need to be adhered to, to allow a product to guaranteed safe in the event of the foreseeable accidents.
I am not the one that can answer your question, but I will try to give your some guidance.
It is not down to selecting a particular type of transformer. It is the whole design, test and manufacture of the completed package that is guaranteed safe.
I believe one of the tests is dropping the package onto a hard surface at a variety of angles and examining how the internal parts behave during the excessive g-force of stopping suddenly.
A secondary requirement, (but again I don't know the regualtions) is that any exposed conductive parts must be safe to touch, or protected from touching.
I have no idea what they do inside a ClassII product that has exposed RCA barrels poking through the insulating package, that makes them safe to touch after that series of foreseeeable accidents have been tested !
I am not the one that can answer your question, but I will try to give your some guidance.
It is not down to selecting a particular type of transformer. It is the whole design, test and manufacture of the completed package that is guaranteed safe.
I believe one of the tests is dropping the package onto a hard surface at a variety of angles and examining how the internal parts behave during the excessive g-force of stopping suddenly.
A secondary requirement, (but again I don't know the regualtions) is that any exposed conductive parts must be safe to touch, or protected from touching.
I have no idea what they do inside a ClassII product that has exposed RCA barrels poking through the insulating package, that makes them safe to touch after that series of foreseeeable accidents have been tested !
Last edited:
A transformer becomes Class 2 if the primary winding is on its own bobbin as there is no path to any part of the secondary. Furthermore the transformer insulation will have been tested for insulation up to and including 2.5kV for flashover. A label or embossed message will be on the transformer or power supply using this type of transformer.
Transformers of single bobbin style and most toroids do not meet the criteria and therefore MUST have the earth lead type 3 core mains cable.
Transformers of single bobbin style and most toroids do not meet the criteria and therefore MUST have the earth lead type 3 core mains cable.
I don't agree.
There is much equipment that is ClassII that is powered by a toroid. Fitting the toroid does not negate the ability for the product to be desgned and tested for ClassII duty.
And all EU transformer for use on our harmonised 230Vac supply have to pass the high voltage test.
Typically this test is at >>1500Vpk.
This is NOT unique to ClassII
There is much equipment that is ClassII that is powered by a toroid. Fitting the toroid does not negate the ability for the product to be desgned and tested for ClassII duty.
And all EU transformer for use on our harmonised 230Vac supply have to pass the high voltage test.
Typically this test is at >>1500Vpk.
This is NOT unique to ClassII
Ok, provided the following
FACTS:
I don't have proper PE at home
I am a newbie re:electricity
I want to be avoid death (I will not start project, if needed)
ASSUMPTIONS:
I would get a decent ClassII PSU (would these work?), and
Double insulate the cables and connections,
Avoid screwing the amp to the chassis heatsink (even avoid a metallic chassis in favour of all wood), and
Avoid exposing anything carrying electricity to external of case (except for switches maybe?),
THEN:
Would I be in the safe zone or in the dead zone?
Thank you all again
Does this mean double insulated? I suspect not, because all the wiring is exposed and the wiring is just as dangerous (or more so) as the bits inside that casing.
If you bought a ClassII double insulated PSU and used that to power your project, then you don't need the project to comply with either ClassI, nor ClassII because the project does not have mains inside it.and
Double insulate the cables and connections,
Avoid screwing the amp to the chassis heatsink (even avoid a metallic chassis in favour of all wood), and
Avoid exposing anything carrying electricity to external of case (except for switches maybe?),
THEN:
Would I be in the safe zone or in the dead zone?
Thank you all again
If you put the ClassII PSU inside the project and take care to protect the mains cable from accidental, or gradually ocurring damage, then again the project does not need to comply with either of the ClassI or ClassII standards.
OK, then I think we're getting closer. I would need to get a classII toroid and follow all the assumptions above. If that toroid linked above does not seem safe to you, would you please point me to the right direction?
Thank you sooooo much again
Most of us build ClassI equipment using good quality mains transformers.
I have never seen a post from a Memeber to say he killed himself !
It's the failed to meet specification rubbish that gets to market, that is the real danger.
Post pics of your assembly in stages. The good guys here usualy spot errors.
Build your self a Mains Bulb Tester.
It too is a mains powered project so it might be confidence building to show it to a qualified electrician so that he can give it a twice over at no charge.
I have never seen a post from a Memeber to say he killed himself !
It's the failed to meet specification rubbish that gets to market, that is the real danger.
Post pics of your assembly in stages. The good guys here usualy spot errors.
Build your self a Mains Bulb Tester.
It too is a mains powered project so it might be confidence building to show it to a qualified electrician so that he can give it a twice over at no charge.
I'm still looking for a somewhat official statement to that effect.
The best that I could find is:
(These products must NOT have a safety connection to Earth)
from:
Double Insulated - A definition - Home of Double Insulated Links on the Internet
That would really be impressive news, talking from the other side...! 🤓
Thank you again. Honestly, i might be missing smth ot it might be the language, but i am not sure i FULLY read you between lines. I appreciate all the help you guys are offering and i'd love to have feedback from pictures as i get going. but it's hard for me to start when i am not really sure i understood the implications.
So, if chassis gets DC power from a PSU located in another case, no problem right?. I'd prefer to mount all pieces in same case though, so i guess i would have to make it as classII as possible, following all asumptions in post #25.
Also, should i open a new thread to ask for help finding a classII toroidal?
you posted a link to a toroid. I could not see any reference to ClassI nor to ClassII.
I believe you cannot just use a ClassII transformer in a piece of equipment without the WHOLE design being assessed and built and tested for compliance to the ClassII standard.
It not just a case of buying a ClassII transformer.
I posted this in post21 and repeated it in post24:
I believe you cannot just use a ClassII transformer in a piece of equipment without the WHOLE design being assessed and built and tested for compliance to the ClassII standard.
It not just a case of buying a ClassII transformer.
I posted this in post21 and repeated it in post24:
one part of a bigger project does not ensure compliance.
But then you also posted (twice) the message in post 31. Sincerely i am getting lost, i appreciate your help but i am not sure where all this is leading me. Of course i will never get any compliance but i know that. I just want to get the safest project i can, knowing the limitation of lack of proper PE.
Thank you again
Thank you again
Last edited:
Just buy a ready made double insulated power brick of a well known brand and be done with it. If PE is unsafe/unknown working with a power brick is almost mandatory. There is a reason laptop computers have such power bricks. Regulations are strict and certification of mains fed stuff is way harder than buying a certified and tested adapter. Saves one from certifying a 230V mains PSU. Second bonus is that you work with safe low voltages and can even touch the contacts of the LV side and still be able to post here However don't stick your tongue to it.
Insecurity on the technical field might lead to unacceptable risks so better avoid those. I started with electronics when I was 8 years old. Then it was custom that you learned by getting shocked. I learnt my lessons. I have touched 230V and 380V (now 400V) more than once and it helped getting much respect for electrical power. I now work with very high energy circuits and my respect has only grown. Got myself educated in this field and I try not to touch 10 kV x kA circuits. Nowadays we live in a rubber tile society with everything certified with countless papers and foreign rules. Anything that might (in the most extreme case) cause some effect with relatively harmless issues is either being removed or draconic measures are taken. This makes me wonder how children of now can learn the profession. This is only beneficial for the guys in the far east that learn faster and are not much hampered by regulations or health and safety rules.
However don't stick your tongue to it.Insecurity on the technical field might lead to unacceptable risks so better avoid those. I started with electronics when I was 8 years old. Then it was custom that you learned by getting shocked. I learnt my lessons. I have touched 230V and 380V (now 400V) more than once and it helped getting much respect for electrical power. I now work with very high energy circuits and my respect has only grown. Got myself educated in this field and I try not to touch 10 kV x kA circuits. Nowadays we live in a rubber tile society with everything certified with countless papers and foreign rules. Anything that might (in the most extreme case) cause some effect with relatively harmless issues is either being removed or draconic measures are taken. This makes me wonder how children of now can learn the profession. This is only beneficial for the guys in the far east that learn faster and are not much hampered by regulations or health and safety rules.
Last edited:
these were the two choices I gave you that I thought gave sufficient safety for your experience.
Neither of these choices say anything about trying to buy a ClassI or II toroid transformer.
Just buy a ready made double insulated power brick of a well known brand and be done with it. If PE is unsafe/unknown working with a power brick is almost mandatory. There is a reason laptop computers have such power bricks. Regulations are strict and certification of mains fed stuff is way harder than buying a certified and tested adapter. Saves one from certifying a 230V mains PSU. Second bonus is that you work with safe low voltages and can even touch the contacts of the LV side and still be able to post here
yeah, i was lookin for a classii toroid but seems to be a unicorn, somi'll probably have to go with power bricks and reduce the complexity of the project, since otherwise i would need 5 of them
really, appreciate all your help guys
apologies for my misunderstandings, i obviously did not properly understand post 24:
"There is much equipment that is ClassII that is powered by a toroid. Fitting the toroid does not negate the ability for the product to be desgned and tested for ClassII duty."
my fault anyway. i gee it now.
yes. based in barcelona, but as i said somewhere, at home i have some plugs with 2 and some with 3 wires, i would not trust on regulations
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.