In an offline, totally enclosed SMPS of 60W for domestic product use in UK and EU and Australia and USA, the creepage distance along the PCB from primary to isolated secondary needs to be >8mm. The clearance distance needs to be >5mm.
How do you find out which section of which UK/European standards document formally states this?
..This brings up a point of interest….i know these creepage and clearance values because of being around for over a decade in the industry….however, if you asked me which section of which regulation standard document I need to look at in order to prove this, -then I would be lost.
In fact, I defy anybody to be able to quote here what is the exact sub-section, section and regulation standard document number which tells what is the safety creepage distance along the surface of an offline SMPS PCB for UK/EU/USA/Australia domestic product of power level <60W. I guarantee that nobody here will be able to do this.
Of course, the huge Corporations can afford to pay an internal department of “standards engineers” to keep abreast of all the standards so that their products conform to all of the multitudinous regulations. Also, they are able to, shall we say “garner the attentions” of the standards institutions so that they can be sure of acquiring the knowledge needed for conforming to the standards.
Small start-up companies simply cannot afford to do this. These small startups not only cannot afford to buy the standards…but also, they wouldn’t actually know which particular multitude of the standards that they must conform to.
And heaven forbid, should a small company accidentally introduce a product into the market that doesn’t conform fully to the standards, then the huge corporations would get one of their highly payed lawyers to ensure that small startup was sued for this. –Putting the startup well out of business. Destroying the competition.
Some say that the standards are simply “common sense”. However, I beg to differ. For example, exactly why is 8mm of creepage needed on a totally enclosed offline 60W SMPS PCB for domestic use? Why wouldn’t 4mm be adequate? 4mm is well above the flashover distance of any overvoltage transient that might occur. For such a PCB placed inside a totally enclosed plastic enclosure with no vent holes, 4mm of creepage would be absolutely safe and adequate…….yet as we speak, small startups are being sued into liquidation because they simply cannot afford the activity needed to ensure total standards conformance. They are being sued because they only have for example, 4mm of creepage where the standards, quite non-sensically, say 8mm is needed. 4mm would have been perfectly safe.
The big corporations win here…the small startups die off, and the jobs go with them.
Has anybody tried to read the standards?...they are written in such a convoluted way that the vast majority of engineers would struggle to fully & accurately interpret them...let alone be cognisant of exactly which of the multitudinous number of standards they actually need to conform to for any particular product.
..and if small companies should make a mistake and fall foul of a standard...then the lawyers of the huge corporations are circling overhead, ready to sue them into non-existence.
Of course, the lawyers of all the big European and UK institutions are too scared to sue the Chinese…..China is big and powerful so they daren’t sue the Chinese……hence we in UK have loads of literally lethal Chinese products flooding us……
such as this lethal LED lightbulb…
Here's another one...
Here's what happens when your country imports fridges that catch fire....
...all the UK’s own companies got closed down because they made some much lesser standards infringement, and were sued out of existence.