I have a string of of festoon lights across the garden powered from a non-RCD protected lighting circuit. I like to have my Bluetooth speaker down the other end of the garden when I'm working, but recently it's battery is getting a bit old and it needs to be plugged in all the time.
So I built an extension cable with a 13A socket on one end and a bayonet cap light 'plug' on the other (not as a permanent installation, just for the occasions I'm using my speaker in the garden, which is a non-earthed appliance in any case). For added safety I put an inline RCD in the cable between the socket and the bayonet plug, in theory so any leakage current from the live to ground/moisture would trip the RCD. So I plugged it all in, and turned the light switch on but the RCD would not 'reset' it just stayed in the tripped mode. I realised I might have got the polarity wrong on the bayonet, so I carefully reversed the orientation of the bayonet connector and tried again. The RCD would still not reset. So I whipped the circuit tester out and tested the input terminals on the RCD, sure enough it was getting 240VAC at the correct polarity, but it simply refused to 'reset'.
So I took the cable and replaced the bayonet with a standard 13A plug and tried it indoors on an earthed circuit, sure enough it started working.
I have read that RCDs do not need an earth to operate, but is it possible the design of certain RCDs requires them to have an earth?
Bit confused by this one.
So I built an extension cable with a 13A socket on one end and a bayonet cap light 'plug' on the other (not as a permanent installation, just for the occasions I'm using my speaker in the garden, which is a non-earthed appliance in any case). For added safety I put an inline RCD in the cable between the socket and the bayonet plug, in theory so any leakage current from the live to ground/moisture would trip the RCD. So I plugged it all in, and turned the light switch on but the RCD would not 'reset' it just stayed in the tripped mode. I realised I might have got the polarity wrong on the bayonet, so I carefully reversed the orientation of the bayonet connector and tried again. The RCD would still not reset. So I whipped the circuit tester out and tested the input terminals on the RCD, sure enough it was getting 240VAC at the correct polarity, but it simply refused to 'reset'.
So I took the cable and replaced the bayonet with a standard 13A plug and tried it indoors on an earthed circuit, sure enough it started working.
I have read that RCDs do not need an earth to operate, but is it possible the design of certain RCDs requires them to have an earth?
Bit confused by this one.
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