(This post was prompted by seeing a recent kickstarter project that some people may wish to use for direct mains control.).
It may be obvious, but using prototyping strip-board is not advisable for mains control.
It may not injure you, but may kill others who use the project, leaving you morally and legally liable.
Some less obvious things to non-engineers are things like strain relief, flame retardant materials, poor crimps, insulating barrier requirements and use of badly rated/designed cheap components that will never be compliant.
Here are some examples of designs not compliant in at least Europe (these images are reduced in resolution/cropped for fair use):
If you want to directly switch mains power, then avoid this type of design too, it is from a recent kickstarter claimed suitable for reflow oven use with a Raspberry Pi:
Here is another example of a UK product called the Mains Switch Widget - this extract is from the user documentation (extract is legal under fair use):
The above rings alarm bells for several reasons. The text in the user documentation snippet above states "this will help to anchor the connections in place" - is this valid according to standards in Europe? According to my understanding the method of clamping has to be well defined, so suggesting that hot glue is not essential but _may_ be used to help is confusing and not well defined, because either the method of clamping is sufficient to comply, or it is not. Also, how does a user know if it is secure? A cable tie can be tied by some people weakly, and by others more securely. Users will not know the test to apply to ensure it is compliant.
Also, the cable tie is wrongly applied to the cable in the photo above, since it should be further back from the unsheathed end. Note that this is not my photo, it is the photo from the product documentation!
Furthermore, for safety, since this is a permanently attached mains cable, the earth connection in the opinion of several engineers, should be the last to be stressed if there is any issue with the clamping of the cable.
When these points were raised with the creator of the Mains Switch Widget on this forum, the text silently changed in the user documentation - see here:
However, it is difficult to see how a documentation change can improve the situation much. The photo still shows the same length wires and cable tie too close to the unsheathed end.
Do check out the comments to the post below, for useful information.
A safe solution that requires no wiring is the Energenie modules - at £16.95+VAT for two of them, it appears well priced and safe. It is also cheaper than the Mains Switch Widget. I tried the Energenie modules out, and it was easy to get them working and controlled by the Raspberry Pi and with other microcontroller boards (they can be controlled via a remote control or via the Raspberry Pi etc.).
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