Can anyone help, I have to layout a PCB with tracks carrying 240VAC @ 16A!!, what is the width of track I would need for 2oz copper track length is around 50mm. Also what track spacing etc for 240VAC is required.
Thanks
Phil
For track widths:
For track spacing:
I'd be careful there, Trevor. 1mm? Sounds way too low to me. What about allowing for creepage, and high voltage transients that can be expected on the mains? There are two areas for consideration really; isolation from the mains to the "user" side, where the above are important, and between adjacent high voltage tracks on the mains side.
Have a look at the section "Track Clearances for High voltages" on
Brian
As someone else has pointed out, these spacings are for electrical insulation only, *not* for safety. If it's a safety issue, the spacings will be much larger, but never having done anything with high voltages connected directly to anything remotely mains-like I've never looked at the requirements. If you are doing something in which breakdown accross the insulation could be a cause for safety concern, then you're going to have to do lot more research than asking in a newsgroup, I'm afraid!
Trev
-- Trevor Barton Isotek Electronics Ltd, 9 Clayton Wood Bank, Leeds, LS16 6QZ, UK. Tel: +44 (113) 275 1339, Fax +44 (113) 224 9827 Remove X from tmb@Xisotek.co.uk before replying. Views expressed are my own and not necessarily those of Isotek Electronics Ltd.
"Phil" wrote in news:bgt8ea$22b$1 @titan.btinternet.com:
I appreciate that the contact is rated to switch that, but things are different if the opened contact is to be used as a means of isolation of the equipment. Most small relays cannot be used (irrespective of their rating) because the air gap is
your thread has now already 6 answers and none of them is your correct answer. You can calculate current, temperature and those things for your track but these formulas are only valid for low voltage traces.
In 230V AC main the question is to be short circuit proof. You mentioned a
16 Amp. Fuse and you should know the loop resistance in mOhms of your complete supply to calculate something. You have to start with the resistance of your wall outlet. Messure voltage without load, apply a reasonable and known load, then meassure voltage again. With the difference you can calculate the practical existing resistance of your wall outlet. In addition, there is your PCB now.The interesting thing is, what happens if there is a short circuit behind your PCB. This depends from the fuse characteristics and what the other loads in the 16 Amp. circuit are. In case of short circuit in mains, there is a short time with currents much above the theoretical 16 Amp. The practical value depends from your total loop resistance and is in the range of a few milliseconds up to a few hundred milliseconds in the range of kiloampere. Your task with the dimension of your track is to make shure, that kiloampere peak blows the fuse instead your copper trace.
Only one thing is shure: If you calculate with 16 Amp you are definitely wrong. Therefore see the risk of short circuit and consider the posibility of additional fuse to protect your PCB. If not possible, support the trace with a copper wire or make a plane shape and connect the thermal pads with minimum 4 legs. Distance between L1 and N should be minimum 8 mm and remember: Its prohibited to feed the protection earth (PE) over a PCB trace.
From what I remember about the regulation in this area, and backed by the other answers in this thread so far, I think I can summarize it all into this statement:
If you don't already know the answers to these, you are absolutely *not* the person to be doing this PCB design. Stop that work right now, and get professional help.
You'll need consulting by someone who actually knows how to do this, or you'll have to drop the project. Usenet may be a great resource of information, but not a substitute for real knowledge where people's heath or even their lives are potentially at risk. Don't bet your income on Usenet recommendations, ever.
You're in serious danger of hurting yourself or others if you get this wrong, and nothing short of actual know-how backed by a formal education and a certificate will leave you in a position where you can even remotely afford the risk of bringing such a thing to market.
-- Hans-Bernhard Broeker (broeker@physik.rwth-aachen.de) Even if all the snow were burnt, ashes would remain.
Come on, people die from cancer, strokes, heartattacks, caraccidents, not from a bad designed power supply. Life is full of risks, so build that power supply. 10mm wide tracks, 6mm apart. No problemo. Use formal coating if used in industrial enviroments.
-- Thanks, Frank Bemelman (remove 'x' & .invalid when sending email)
No, people do die from bad power supply designs, although it's pretty rare these days I'll grant, but that's due in large part to there being formal specifications and regulations. There is a happy medium somehwere inbetween the IMHO over cautious view of Mr Broeker and the somehwat cavilier view of Mr Bemelman. The OP should now have enough information to go look at some formal standards, and then lay out his PCB in the knowledge that he is being both competent and careful. In that respect, USENET was a good place to start. It's up to him now to take the infomation we've given him and turn it into a good design, and he now has enough information to start to be able to figure out how do so, which is more than he had before he posted.
Trev
-- Trevor Barton Isotek Electronics Ltd, 9 Clayton Wood Bank, Leeds, LS16 6QZ, UK. Tel: +44 (113) 275 1339, Fax +44 (113) 224 9827 Remove X from tmb@Xisotek.co.uk before replying. Views expressed are my own and not necessarily those of Isotek Electronics Ltd.
Mine too Frank, but you and I are not a lawyers.
In article , Frank Bemelman writes
Not only do people die from badly designed power supplies in most parts of the world there is a lot of legislation on power supplies for equipment.
You may find yourself open to prosecution even if it does not go wrong.
Regards Chris
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ \/\/\/\/\ Chris Hills Staffs England /\/\/\/\/\ /\/\/ snipped-for-privacy@phaedsys.org
"Chris Hills" schreef in bericht news:LHoAyYEY2TO$ snipped-for-privacy@phaedsys.demon.co.uk...
bericht
Kids like stacking things. Give 'm ten 9V batteries and see what they can build with that. Pure innocense can build a lethal weapon, and it is for sale in every shopping mall.
So, use your common sense. Build decent stuff. But don't turn a mice into an elephant.
-- Thanks, Frank Bemelman (remove 'x' & .invalid when sending email)
Certainly. However, reviewing the original posting, I see nothing to indicate the application of this power supply. It might be going into consumer equipment. Assuming *any* level of common sense on the part of the appliance-buying public is sheer unmitigated insanity. ("Caution! Hot Apple Pie will be hot after heating!").
Also, if I buy an industrial system of some kind (say, a speed-controlled pump for volatile liquids), I expect that the manufacturer has taken all appropriate safety precautions.
I'm not directly predicting any dire outcomes, just gently pushing my opinion that you were being a little cavalier and devil-may-care. The answer to the question "What's the worst that could happen?" is "Almost anything".
In article , Frank Bemelman writes
The local law takes precedence over any "common sense" and there is a lot of legislation for power supplies.
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ \/\/\/\/\ Chris Hills Staffs England /\/\/\/\/\ /\/\/ snipped-for-privacy@phaedsys.org
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