Bench power socket

You need a bench power socket. You use a 4-way socket and all is good… Well sort of. What I really want is something with some weight to it and a good earth connection so I can stick my anti-static strap to it.

Most power strips do not have a separate switch for each socket. Something that I really like when doing stuff. To be able to quickly and safely switch off power to a given socket is really nice.

Remember the school workbench power sockets that were built into the desks in science? That is the sort of thing which would be useful. If it was portable that would be best.

Looking online I found this:

If we put some rubber feet on it and then add some strain relief to the cable along with a earth link.

To ensure that everything is safe we put a 1Meg ohm resistor to the earth connector for safety. The anti-static strap typically have this already but no harm in having this extra safety margin.

An anti-strain relief grommet is essential. I found the following in my parts bin which is ideal:

It allows a simple 10mm hold to be drilled into the case and the grommet has a friction grip that tightens around the cable nicely when doing it up.

Some nice rubber feet on the bottom:

The earth connection will be made using a banana socket, but one with a thumb-screw just because that was available and might be useful. The main think is that is allows the anti-static strap to be plugged in, safely.

Well that was a mistake! Measuring the resistance from ground to the anti-static socket shows ZERO ohms… Ah! That is not good. The case is metal and when drilling the hole that exposed the surface and made a lovely clean electrical connection, effectively bypassing the 1Meg resistor! DOH!

So, replacing this with another connector (actually the one I originally had in mind but could not find) with a plastic surround fixed that problem:

Drill out the hole and mount it on the back of the case:

Testing this time was much better, showing the 1Meg series resistance:

And testing the other connections all returned a good result. The final thing:

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