| Electronics > Beginners |
| Earth leakage fault - consider using an whole lab insolation traffo - discuss |
| (1/3) > >> |
| MadScientist:
Hi, IN my home lab/office I have the usual test gear , small CNC mills etc Annoying my house which i bought three years ago , occasionally tripos its RCBO for no apparent reason , typically flicking the RCBO on again ,restores the status quo Tracking down the issue is exceeding difficult , the RCBO protects essentially two mains rings and is not on the lighting circuits ( The house was built in 1995 and is coded correctly for the time ). This year in 12 months I have three-four trips I will replace the RCBO soon and Im considering putting a separate one on each main ring to start the process of segregating the problem In the mean time I have two choices , Isolate the whole lab on a 230-230 isolating traffo, ( to eliminate leakage currents from the lab ) or putting the computing resources on a UPS ( which is what I am doing first ) The UPS isnt really a solution long term , the long term solution is no trips ! The isolation traffo isnt a long term idea, but would at least eliminate over 12 months is anything in the lab generating earth leakage currents, but I have had the RBCO trips when nothing was powered on in the lab . I am aware of the common mode issues with isolation , but putting the whole lab on one would generally eliminate issues of inadvertent grounding After that Im not sure how to track down this elusive fault , due to the infrequency of its occurrence ideas ? Thanks Dave |
| vk6zgo:
Some heavy domestic appliances have a bit too much leakage by design to be used on an RCBO, & in Australia are allowed to be driven from an unprotected source. Maybe they aren't in your country-----where are you? In this country, things like refrigerators, washing machines & dryers are all used from switched power sockets, & are used RCD/RCBO protected. Hot water systems, stoves, etc are hardwired, & some of those may be in the group which will be marginal with an RCD/RCBO. The problem could be a faulty RCBO though---- such things do fail, eventually, just as conventional circuit breakers do. |
| madires:
An isolation transformer for the whole lab is a bad idea because you wouldn't notice a bad device besides other issues. I'd install a dedicated RCD (plus mains) for the lab, one (plus mains) for the data center, and also one for each mains ring (UK?). This way you would have only a partial blackout if one of the RCDs is triggered. |
| MadScientist:
My next step is to consider putting the lab on a seperate RCBO , its not " too " awkward as , my lab is close enough to the main distribution board , but as always trying to run twin +earth wires through an existing decorated house is a PITA. Im in ireland , and the practice here is as per the UK. Heavy loads like Cookers etc are not on a RCBO , ( in 1995) , newer houses now have all house RCBOs however Ill replace the RCBO as a first step , thats the easiest and a have a 500W UPS coming to at least protect the computers its a bugger of a problem to track down |
| MadScientist:
--- Quote ---because you wouldn't notice a bad device besides other issues --- End quote --- There is nothing to stop me fitting a local RCBO to my safety transformer , which would detect local leakages to the PE wire on equipment connected |
| Navigation |
| Message Index |
| Next page |