Why did I need to turn off RCBO to get lights working again?

[ericmark]

I use energenie mihome smart switches in the bedrooms so I can turn lights on/off with a remote from my bedside.

They are rated with a minimum of 5 watt, and have no neutral, and have worked for a couple of years powering three GU10 spot lights, however it left one side of the room a little dark so my son fitted an extra pendent, so now a BA22d bulb as well.

At the same time he fitted another three GU10 light bar into wife's craft room with three smart bulbs, so I swapped my standard bulbs for her smart bulbs, then I had a spare smart E27 bulb so used a converter and also fitted that to my bedroom so I can dim all the lights and also change the colour temperature, don't need that feature, but the bulbs were there, so used them.

So then the error, windows open at night did not want flying insects in the room, so turned off three lights and dimmed the last one, ups less than 5 watt so smart switch turned off, knew what was wrong, so removed all smart bulbs, and after no bulbs left in place, then fitted standard bulbs, but smart switch would not work.

So down two floors to consumer unit, switched of the lights RCBO, for upper floor did a few odd jobs, i.e. left a little time, turned back on and smart switch working again. Will not make that mistake again.

However why did it not reset when I removed all the bulbs, why did I need to switch off RCBO? To my mind both did the same, and removed any potential difference across the switch, so why did removing bulbs not work, but turning the RCBO off and on did?

I have not refitted the smart E27 bulb, leaving at least one standard bulb in the lights, so will not get a repeat of the problem. Likely once I have a zigbee remote I will remove the energenie switch, but although not a problem any more, still can't work out why removing bulbs did not get switch working again.

 

[bernardgreen]

The Smart Switches may use PolyFuses on their mains inputs as protection.

If the PoyFuse is tripped then it will remain tripped until the mains supply is removed and the PolyFuse can reset itself.

 

[SimonH2]

Possibly with too low a load, the electronics don't have enough power (internal voltages too low) and can "lock up". Unless you remove all power - either by turning off the supply or removing all the bulbs, then the electronics don't recover. Electronics, especially digital stuff, can do some very strange things when run from too low a supply voltage.

 

[ericmark]

My thoughts were removing the load i.e. removing all bulbs would have been the same as turning off the RCBO no neutral to switch, so both should have removed any current flow through the switch so it would have reset, however it did not reset removing bulbs, it did reset turning off RCBO.