Guest scumbag Posted January 13, 2018 Share Posted January 13, 2018 (edited) As simple question (hopefully) - would one of these isolation transformers (240V - 240V) still provide protection from electric shock via an RCD device fitted on my electrical switch board? http://www.radioparts.com.au/product/54153615/iso2000es-240v-2000va-isolation-transformer-mains-electrostatic-screen#.WlnvHa6WaUk There is mention of "All enclosures are earthed on the input side" - does this mean that after the device there is effectively NO earth (on the device side, not the mains side)? If so, could I employ an RCD after the device to ensure safety. Any advice would be appreciated. Edited January 13, 2018 by scumbag Link to comment Share on other sites More sharing options...
Guest scumbag Posted January 13, 2018 Share Posted January 13, 2018 Actually I just found this article - http://www.powerinspired.com/isolation-transformer-need-know/ It seems to cover the above question. So an RCD or trip will still work if a device develops a fault. Link to comment Share on other sites More sharing options...
stereo coffee Posted January 13, 2018 Share Posted January 13, 2018 What is called Safety Earth requires the chassis metal be earthed to the IEC earth tag that then connects to your house wiring earth, which should include a copper rod driven into the actual ground. http://sound.whsites.net/earthing.htm Using isolation transformers does not remove or change the need of safety earthing. Link to comment Share on other sites More sharing options...
Guest scumbag Posted January 13, 2018 Share Posted January 13, 2018 (edited) 2 minutes ago, stereo coffee said: What is called Safety Earth requires the chassis metal be earthed to the IEC earth tag that then connects to your house wiring earth, which should include a copper rod driven into the actual ground. http://sound.whsites.net/earthing.htm Using isolation transformers does not remove or change the need of safety earthing. OK it is grounded according to the manufacturer's literature. My question is, will it allow an RCD to trip if a device develops a fault? Edited January 13, 2018 by scumbag Link to comment Share on other sites More sharing options...
stereo coffee Posted January 13, 2018 Share Posted January 13, 2018 But where is the RCD located ? If it is at the isolation transformer output as an additional safety measure, you are likely to get the first RCD behaving strangely. Using one RCD in this case at the isolation transformer output protects when using that appliance, to the degree that an RCD offers protection, noting there are ratings of RCD https://en.wikipedia.org/wiki/Residual-current_device This sums it up pretty well. http://sound.whsites.net/articles/iso-xfmr.htm "Use of an isolation transformer should be limited only to equipment where it's essential. The rest of the time, equipment should always be connected to the mains in the same way as it is when being used normally. " Link to comment Share on other sites More sharing options...
andyr Posted January 13, 2018 Share Posted January 13, 2018 9 hours ago, scumbag said: As simple question (hopefully) - would one of these isolation transformers (240V - 240V) still provide protection from electric shock via an RCD device fitted on my electrical switch board? http://www.radioparts.com.au/product/54153615/iso2000es-240v-2000va-isolation-transformer-mains-electrostatic-screen#.WlnvHa6WaUk There is mention of "All enclosures are earthed on the input side" - does this mean that after the device there is effectively NO earth (on the device side, not the mains side)? If so, could I employ an RCD after the device to ensure safety. Any advice would be appreciated. You need to ask Tortech. Some mfrs of 'isolating transformers' take the word 'isolating' to mean that earth is also isolated - ie. the input earth does not follow through to the output earth. AIUI, this means that an RCD will not work. Other mfrs of 'isolating transformers' take the word 'isolating' to mean that only the active & neutral wires are isolated - by means of magnetic coupling - and the earth wire follows through to the output. The isotran which Siros made for me a couple of decades ago is like this. So an RCD works as normal. Andy Link to comment Share on other sites More sharing options...
Guest scumbag Posted January 13, 2018 Share Posted January 13, 2018 59 minutes ago, andyr said: You need to ask Tortech. Some mfrs of 'isolating transformers' take the word 'isolating' to mean that earth is also isolated - ie. the input earth does not follow through to the output earth. AIUI, this means that an RCD will not work. Other mfrs of 'isolating transformers' take the word 'isolating' to mean that only the active & neutral wires are isolated - by means of magnetic coupling - and the earth wire follows through to the output. The isotran which Siros made for me a couple of decades ago is like this. So an RCD works as normal. Andy Tortech says this on their website "Earthing is NOT carried to Outlet Socket, Hence Isolated and Floating" So that looks like a "no" then. Bummer. Link to comment Share on other sites More sharing options...
rocky500 Posted January 14, 2018 Share Posted January 14, 2018 (edited) I bought RCDs to go on the output of my balanced transformer, just for the extra piece of mind if something goes astray. http://www.clipsal.com/Trade/Products/ProductDetail?CatNo=951&c=1&ms=3&s=2&mg=317&g=3173593 Edited January 14, 2018 by rocky500 Link to comment Share on other sites More sharing options...
andyr Posted January 14, 2018 Share Posted January 14, 2018 9 hours ago, scumbag said: Tortech says this on their website "Earthing is NOT carried to Outlet Socket, Hence Isolated and Floating" So that looks like a "no" then. Bummer. Then look for a different mfr of isotrans, scumbag. Siros was taken over by a Brisbane company - you may be able to find out who? Alternatively, I don't use mine any more - so you might like it? It's a 1KVA tranny - it weighs 16kg but is not very large - so road transport to Brissie shouldn't be that great, I would've thought. Attached is a pic of its size, relative to a CD case. It has 1x IEC socket for input and 6x output sockets. Andy Link to comment Share on other sites More sharing options...
Guest scumbag Posted January 14, 2018 Share Posted January 14, 2018 25 minutes ago, andyr said: Then look for a different mfr of isotrans, scumbag. Siros was taken over by a Brisbane company - you may be able to find out who? Alternatively, I don't use mine any more - so you might like it? It's a 1KVA tranny - it weighs 16kg but is not very large - so road transport to Brissie shouldn't be that great, I would've thought. Attached is a pic of its size, relative to a CD case. It has 1x IEC socket for input and 6x output sockets. Andy Sign me up! EMMACHESIT? Link to comment Share on other sites More sharing options...
Recommended Posts