Voltage drop

[Spark123]

The top one looks like an electronic driven one from a plug in type Power breaker.
Never seen one that looks like the bottom one - I notice the black and white wires - is it aimed at the american market? Reading the literature it appears to be some sort of RCBO.
Afaik there isn't a requirement to RCD protect RLV systems, however some instrument systems may require 110v above earth systems.
I have not had much of a problem with the normal torroidal type RCDs for use in a 110v system. One thing that needs consideration is that the test resistor may not be small enough to cause a sufficient imballance if the voltage is not great enough.
My Megger MFT can trip RCDs when testing R1+R2 with is set to ohms range - think that is only about 12v DC @ 200mA

 

[ericmark]

1992 was a long time ago and nuclear electric is only client who every wanted RCD's on RLV system and in the end we did get them to relax on this requirement. I see that special RCD's for 110 volt systems are now on the market but at that time we had a real problem locating any and when we did it was one or two not the 50 to 60 we would require.
I have been given a very low voltage at which RCD's should work I think down to 50 volt but when we did tests the 240 volt type we had would not even work on 110 volt never mind 50 volt.
On the last job we did see a few active RCD's fitted on 110 volt gear which caused a lot of problems as to try and look environmental friendly we also had generators which when not under load would tick over and only rev up when they got a demand. As these went to tick over the active RCD's dropped out and would not re-set. How do you create a load if you can't switch the RCD on? And needed a fair load too. So had to leave 110 volt quartz halogen lamps plugged in.
So much for environmental friendly generators?

 

[Spark123]

Like I said, I don't believe there is a requirement to RCD protect RLV systems so there is no need for the RCD to be there in the first place.
I can't think of any of our RLV systems which are RCD protected.
I have seen some yellow in lead type RCDs available for 110v systems, however these are over and above the normal requirements.
Active RCDs are electronic RCDs and require a supply to operate.

Bog standard RCDs - as in the ones with no electronics in them such as the Wylex WSES30/2 - work by monitoring the AC magnetic field caused by current flowing in the two primaries. Should the two primaries not cancel each others magnetic flux out the resulting flux is picked up in the trip coil which is connected to a solenoid which causes the breaker to open. They operate on Current, it doesn't matter if the voltage is 55vAC, 110vAC or 240vAC, as long as the missing current exceeds that of the trip it must open. The only issue I can think of will be the resistor in the test mechanism will not create a missing 30mA.