STEOL RCD

Interesting idea! If the RCD tests itself, and passes, then all is well; but if it fails, it must trip and it must trip permanently. ?

"The WA STEOL based RCD performs self-testing every 2 to 3 seconds throughout the life of the product. It does this by generating a residual fault current within the RCD and this fault current is detected. "


O.K., so the device wears its electronic parts out by using them every 2 to 3 seconds, BUT how does this actually test the correct operation of the mechanical moving parts, i.e. the opening of the main electrical contacts. What would happen if the innards were invaded by micro-spiders that block up the mechanism?


Or have I got this wrong?


Have a good 2020.


Z.

I have seen one of these mythical beasts. About 6 or 7 years ago one of my students was involved in the installation of the power to street cabinets for the fibre network. In each one he was installing one of these self testing RCDs and brought one in to college.


It was a well known make but I cannot remember who. It was basically a 61008 RCD with an actuator module on the side fitted with an arm that re-set the trip lever RCD after test. Firmware inside performed a regular test at an interval I cannot remember and the actuator re-set the device. If it failed the test or tripped through a fault a message was sent to a control center for an engineer to attend and investigate. The equipment in the cabinet was backed up by a small UPS.

Sounds similar to the "auto re-closing" RCDs we talked about a year or two back (e.g. the Gewiss version - https://www.gewiss.com/ww/en/products/experience-catalogue/catalogs/series/power/90-restart-range-automatic-reclosing-devices ) - they had an auto test as well as auto re-close function.

   - Andy.

Well done Andy it was the Gwiss model I saw.