I am not sure how to formulate this in a proper way. But I think we should not discuss topics in this forum. That involve the use of mains voltage without an isolating transformer. Typical examples of this would be transformerless power supply and home-brew light dimmers. Some exceptions must be allowed here. Like help using commercial products. As those should have proper approval. Main voltage controlled by a mechanical relay/SSR should be considered OK I guess.

 

Just a thought.

RB should add that one should use an isolation Tx just to build and test it.

 

How about power supplies in general?

Electronics is not inherently safe. Low voltage circuits can be made relatively so, but even then I could create lethal voltages and currents with something simple as a 9V battery and a handful of components.

This site is not strictly for beginners, we also discuss advanced concepts here, college level. We try to cover the basics, but if we get carried away we run the risk of going too far, dumbing the site down to the point where only high school or freshman electronic students can use it.

 

How about power supplies in general?
Electronics is not inherently safe. Low voltage circuits can be made relatively

If we are talking about old fashion linear power supplies with a proper isolation transformer it should still be OK, and has always been considered OK on this forum. What I personally dislike are non isolated mains project. Like transformerless supplies(already banned) and home-brew light dimmers. To this I can also include mains operated light organs to some extent. It may be other applications but at the current moment I can not come up with other examples

 

The real purpose of the restrictions on AAC is to protect the website and the owners, administrators and moderators of the website from litigation and not so much to ensure the safety of experimenters, hobbyists and professionals.

AAC is a free voluntary service to promote the pursuit of the art and science of all things electrical and electronic. AAC has no obligation to provide any service to the public or its members.

AAC can choose to limit all discussion to unpowered circuits, or to 9VDC or 30VDC or whatever it chooses and refer all other requests to other sites, but that would be absurd and ridiculous.

So where to draw the line?

Circuits that control AC power using a mechanical relay might be allowed. By extension, that would also include solid state relays, thyristors, light dimmers and color organs.

In my opinion, the intent and scope of "transformer-less power supplies" is clear. A circuit that functions as a "power supply" is clear. A PV solar charger is a power supply and transformer-less but AAC would not prohibit discussion on such designs.

Clearly, a "transformer-less power supply" refers to any AC mains powered circuit whose purpose is to transform the AC power to a usable form (step up or step down) without proper isolation at the AC mains connection.

In my opinion, this would prohibit discussion on switched mode power supplies that do not employ an isolation transformer at the AC mains input.

The standard description of a transformer would prescribe a primary winding and a secondary winding. In my opinion, a power supply that meets the requirement for inclusion for discussion would have the AC mains connected via a fuse and switch on the LIVE connection and then connected to the primary winding of the transformer. The return from the primary winding would be connected to the NEUTRAL connection of the AC mains.

An exception occurs when the power source is via a sealed AC adapter or "wall wart".

This is my opinion and may not reflect the opinions of the other moderators.

 

Just my own dumb thought on this type of thing. Is it possible to make projects like this available to members that have over a certain number of posts? Many or even most of the people that would be adversely affected/harmed by something similar to this would be shut out from the information that way. Many with no real interest in electronics or learning electronics, are "fly by" posters.

Doing this would open up projects/information for the ones that are willing to stay around. And want or need more advanced information.

 

So where to draw the line?
Circuits that control AC power using a mechanical relay might be allowed. By extension, that would also include solid state relays, thyristors, light dimmers and color organs

Here I disagree and the reason is. Any relay rated for mains voltage or commercial SSR will be required to have some sort of approval to be legal to sell. A hobbyist triac dimmer will not have such approval and will be as potential hazardous (fire shock etc) as any mains type transformerless supply if it is poor built. And the build quality is not something this forum not can control. That is why I prefer that none of our members should not in any way be encourage to build such a device at all.

 

Gosh it must be a miserable life to live when you are ruled by the "what if" monster.

People will do what they want to do regardless of whom complains or tries to prevent them from doing it based on their own perceived views of what is or is not dangerous.

As far as "what if" someone does XYZ based on instructions they got from some internet forum.... Seriously now?

How do the forums dedicated to people who make custom archery bows and related gear, guns and firearms, pyrotechnics, knives and blades, auto racing, motorcycle racing, rock climbing and hiking, large game hunting, metal working/forging, biology and home health para science, overunity, legal advice, marriage advice, engineering, home DIY construction and who knows what else all get way with having countless random people from all over the world handing out advice to others without getting sued to death when ever some one takes bad advice and does something terrible with it to themselves or someone else??

Seriously if someone is worried about hobby level electronics being dangerous go do 10 minutes of reading on a pyrotechnics or guns and ammo, or archery, or knives and blades hobbyists site.

Some guy with a transformerless power supply or home made light dimmer is going to come off as a pretty mild safety concern compared to whats casual conversation over there.

 

You're entirely right, TCM, but the personal ownership of this site gives the owner his choice of what he wants his site to be. End of discussion from my point of view.

 

Gosh it must be a miserable life to live when you are ruled by the "what if" monster.

No my life is not all miserable. My reason for concern is due to I for many years ago was involved in a consultant team working for an insurance company. My part was to help in determine the cause of fire in burnt-out ruins. We could often trace the reason back to improvised and not legal equipment connected to the mains. Like homemade drying cupboard, home-brew mains power control in all variants, home-brew electrical mains wiring and so on. It is in light of my experience from this. I recommend that this forum do not that encourage amateurs to build things like home-brew light dimmers. You can ridicule all you want. I comment based on dry facts in this case.

 

@t06afre,

Thank you for expressing your concern and caring for the AAC membership.
You are entitled to your opinion and are free to report any posts you might consider dangerous, illegal or insulting.
But, at the end of the day, your opinion alone cannot change our moderating line. 3 out of 4 moderators have replied that this circuit will not be moderated and this is how it shall be.

 

Good to explain your point of reference. I was getting puzzled about it. Dead people are a serious problem.

This seems similar to "lawyer medicine" where all sorts of expensive precautions, tests, and approvals are required if you cough when he has not asked you to turn your head. Strantor and I are not amateurs, so I guess that doesn't apply to your concerns.

 

The reasons the rules are as they are is an extensive discussion about our rules set around 2009-2010. I wasn't a mod then but I was very active in it. Frankly a lot of the discussion offended a lot of people, and it still does. People do not like to told they can't do what they want, even if it is they will not get help on this site.

Most of the rules are to protect the folks working on this sit, as Mr. Chips said. We can't control what people do in their homes, but we can control our liability.

I've also made the point of competence. I suspect The RB is among the most competent on this site.

 

Hello,

I am not a favorite of powering a PIC through a capacitor.
Isolation would be a pre for safety.
You can control the triac with an optocoupler like the ones in the MOC series.
This MOC can easely be controlled by a PIC.
The PIC itself can be powered with a tiny SMPS powersupply.

Bertus

 

problem is cost.

 

And powering a PIC from AC mains via a capacitor falls into the scope of "transformer-less power supplies" and presentation and discussion will be prohibited on AAC.

 

My personal point of view as cheap as wall warts are it is silly not to use them.

 

Gosh it must be a miserable life to live when you are ruled by the "what if" monster.

Here's a "what if" for you. You build a circuit for your mother. While it was installed and connected to the mains, the house caught fire and burned to the ground. The insurance investigator proclaimed that circuit was the cause of the fire that destroyed your mother's home and recommended the insurance company not to settle your mother's claim.

What would your mother think of your "circuit" and your part in destroying her home, her belongings, and her memories?

Now I know you would probably design some fail-safes, but you can not guarantee that from anyone who posts a circuit from the internet. I couldn't guarantee they have a clue about safety.

 

It actually takes a bloody long time to learn all the things that can go wrong. Several of my employment positions first rule was, "Put it back the way it was built in the first place". New hires can't be expected to know all the hoops we had to jump through to get the approvals for this stuff.

Personally, I got my last red tag after I had been in the business for 8 years. Two stranded wires connected with a clamping type screw terminal is illegal? Never crossed my mind until the inspector pointed it out.

 

It depends on the connector approvals.

Inspections in MN. are run much like forums. It's all about liability.

Did you know that we can't install a lug on a ground clamp to accommodate a larger wire? (although you can buy a clamp with a lug attached)

Speaking of lugs. Temperature rating of lug must match the temperature rating used for wire sizing.

You can't use a crimp terminal on a stranded wire to terminate at standard wiring device. (outlet or switch)

You can't use a breaker in a GE (for example) panel, other than a GE.
Even one that's made to fit. Like from Home Depot.