I'm sorry,but I can't go along with all the paranoia about mains supplies.
Yeah a bit like Black snakes are generally timid and will always try to flee, just a bugger when you inadvertently corner one of the buggers. Same applies to mains terminals, a bit of respect and they are quite safe, add ignorance, stupidity or blind faith and they can bite you bad. Bad as in final, no more chances.
In the days before the prevalence of solid state equipment,built in mains supplies were the only practical way to supply power to home made Electronic equipment.
In the days I got my drivers licence, cars only had front seat belts, should we head back to that piece of memory lane too?
Hundreds of thousands of "homebrew" radios & other devices were made over tens of years,using transformer/rectifier supplies,with a vanishingly small accident rate.
Which in some cases was more good luck than good management. Are you really proposing a knot in a two core mains flex is still sufficient?
Anyone with enough common sense to not injure themselves doing any of a hundred other everyday activities
can safely create mains operated Electronic Equipment by following a few simple rules
I can only agree but some things you are best to get some help with. Sure guys have taught themselves to fly helicopters and all kinds of crazy shit, but you forget you and I have both done some form of trade and industry training. Even if it wasdone in the days of the dinosaur.
(1) The only mains connections you need to make for a transformer/rectifier supply are in the primary circuit,& these connections require the most care.
True, and the safe way of doing this is second nature to many of use. For new chums there is lots to consider. Many listed in my previous post.
(2) Apply Uncle Vernon's tips.
They are tips or rules I've learnt. Ponder most and you can see the disaster that preceded their general adoption.
I think his tips (2)& (3) require a little closer examination
Everything deserves close examination. It's the Internet people write all kinds of good and bad advice here.
UV(2)---Nice if you just happen to have a tame electrician or "Ginger Beer" on tap!
In many cases,you don't,so you may have to make do with an advanced hobbyist,or if you have to do it yourself,be like Santa,make a list of the things you have to check in the primary circuit,& check it twice,or thrice,or as many times as you need.
If you still aren't happy,apply UV(2).
Sparkies are like about like assholes (and some behave that way), cannot be too hard to fine one, lots of them are cousins and uncles after all. I'll concede that advanced hobbyist is just as able, but they can be equally difficult to locate. The problem being advanced is subjective, anything from the guy at Jaycar who must know stuff because he has a beard through to seasoned hams. Some are not as advanced as they think they are, which is why I was cautious to suggest it.
UV(3)----Again,nice if you've got an RCD ,but if you are in an old house,you may not have one.
A plug in one can be had for around $20, an good double pole plug in one for closer to $80. A lot cheaper than, and a lot safer than, an isolation transformer suggested elsewhere.
Fear not,however,as by paying a bit above the normal price for an extension cord,you can get one with a built in RCD.
see above
We didn't have RCDs in my day,but I never connected the active line to the metal chassis---never have for that matter.
Still, I would have definitely used a RCD if theyhad been available.
More fond recollections of core balance relays and a world connected through rewireable porcelain fuseholders. Yeah nowadays I like to use an RCD by default. Beginners are likely in to be in rented homes, student slums etc. I'd recommend springing for an plug in RCD.
I reiterate,mains wiring in Electronic projects is not like Crocodile wrestling,or milking venom from Taipans,& the
application of a fair degree of commonsense makes it a simple & safe activity.
Not when you know what you are doing, Steve Irwin would have probably approached Mains with the same trepidation you or I would approach a croc.
After all,you have to learn about it sometime!
This does not mean that messing about with fixed building wiring is by any means as simple or safe,& I believe many of the posters are addressing this from that perspective.
I hear what you are saying VK6ZGO, we don't need the fun police, or bullshit OH&S which is nothing to do with safety anyway. I don't wan to be the fun police and don't want to suggest nonsense like tradesmen only wiring.
Many more people perish from suicide or road trauma each year than by crocodile attack or electrocution, even so both still deserve a degree of respect.
Dave's suggestion of a plug pack supply is probably the best way for a beginner's first few projects, particularly now modern switch mode ones can deliver cheap useful current.
Well,Unc,you managed to read a lot into a few comments!
What I was trying to convey was that if people could make & safely use mains powered equipment back in the days of "a knot in two
core flex",that it should be quite safe to make one now using readily available modern hardware.
For instance,using a "Chassis male with switch & fuse" IEC inlet ,Jaycar part No.PP-4003,it is possible to reduce the mains component of a project to 3 connections-an Earth connection,& Active & Neutral connections to the power transformer primary.
Contrast this with installing a fixed power cord,with a cord clamp (or a knot ,way back when),terminating the A & N connections on a tag strip,& the Earth (if you used one) to a daggy old 1/8" whitworth screw through the chassis,running Active & Neutral to the switch on the front,(probably a "switchpot") then back to another couple of tags on the strip,then to the transformer primary.
A lot more chances to make a mistake!
The only disadvantages of using the chassis mount IEC connector,complete with switch & fuse,are :-
(1) The switch is on the back of the equipment
(2)The fuse is an M205 type,which most of us don't have lying about in our junkbox.
(3) Uncle Vernon doesn't like IEC cables!
By the way,I think that "the connector not fitting in a kid's mouth" bit
is an urban myth,as the old jug plugs were very similar in size to an IEC plug,plus the Philips type shaver cords have been around forever,& are small enough to swallow!
The people on this forum seem to be of two kinds;
Those who adopt a "Here be Dragons" approach to mains circuitry,& won't approach it,unless in full armour,& those who can't wait to hang their new Rigol across the mains & blow the S----t out of it!
VK6ZGO
PS:- If this posting is a bit rough around the edges,it is due to dear old iiNet,who are running very slow,& dropping out,so it's a matter of posting when you get a window of opportunity!