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| Mains sockets with no earth |
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| nctnico:
--- Quote from: themadhippy on January 18, 2021, 12:59:59 pm --- --- Quote ---You still have RCD protection without an earth. --- End quote --- if you dont have an earth your rcd will not work.were does the fault current go as there is no path for it to travel.Dont believe me then remove your main incoming earth and bonding and short earth to live or neutral somewhere on the consumers side and see how long it takes for the rcd to trip --- End quote --- In that case you don't have a problem. If there is no ground the current can flow into then you can't get a shock! --- Quote from: Zero999 on January 20, 2021, 09:21:02 am ---It's true that RCDs will work, if the appliance lacks an earth connection, but an earth is required at the supply side. RCDs need the mains supply to be earth referenced, --- End quote --- Almost right. RCDs need the neutral to be earth referenced at the primary side. But after that you don't need earth in the installation. It is assumed the building is somehow grounded (and in 'wet' rooms like the bath room it is often mandatory to ground the floor and every metal object). |
| Someone:
--- Quote from: michael@metgen.tech on January 20, 2021, 03:38:36 am --- --- Quote from: Someone on January 19, 2021, 09:47:57 pm --- --- Quote from: michael@metgen.tech on January 19, 2021, 02:26:50 am ---So, it sounds to me as though I should install some three-pin sockets (US style), on extension cords, with the earth connectors disconnected from each other - that would produce the same effect as cutting off the three-pin plugs and putting on two-pin plugs. Then I need to stop worrying about the absence of an earth connector? --- End quote --- No, equipment that has a mains earth pin usually relies on it for safety and/or EMC. Removing that connection is a very very bad idea. If you don't understand the standards/requirements (which is plainly obvious from your posts so far) then suck it up and hire a professional to do the job. Just ask an electrician to put modern grounded points everywhere and its done. --- End quote --- Your comment doesn't really make sense - obviously not coming at this from a Japan perspective. The standard in Japan is to NOT have any earthing. There are no "modern grounded points". The problem I have is that I have equipment that is not Japanese, has earth connectors and, for some, an uninsulated metal case. So "hiring a professional" won't change anything. I am trying to better understand of the risks that I am actually exposed to by following the local standards and if there are any workable mitigations. --- End quote --- https://ja.wikipedia.org/wiki/%E9%85%8D%E7%B7%9A%E7%94%A8%E5%B7%AE%E8%BE%BC%E6%8E%A5%E7%B6%9A%E5%99%A8 --- Quote ---the 2005 revision of Extension Regulations 3202-3 In new homes, etc., it is recommended that all outlets in the home be equipped with a grounding electrode regardless of the usage phase --- End quote --- So yeah, there is that whole its the recommended way to do it thing, in your specific country, according to their specific standards. Some of us have do have a solid international view. |
| Zero999:
--- Quote from: nctnico on January 20, 2021, 10:03:53 am --- --- Quote from: Zero999 on January 20, 2021, 09:21:02 am ---It's true that RCDs will work, if the appliance lacks an earth connection, but an earth is required at the supply side. RCDs need the mains supply to be earth referenced, --- End quote --- Almost right. RCDs need the neutral to be earth referenced at the primary side. But after that you don't need earth in the installation. --- End quote --- That's what I said. Read it again. |
| michael@metgen.tech:
--- Quote from: Someone on January 20, 2021, 11:38:09 am ---https://ja.wikipedia.org/wiki/%E9%85%8D%E7%B7%9A%E7%94%A8%E5%B7%AE%E8%BE%BC%E6%8E%A5%E7%B6%9A%E5%99%A8 --- End quote --- Excellent, I had not found that, thank you. The only issue with my new place is that it was built in 2002 - pre the 2005 changes. Also, unless you have lived here, you would find it hard to believe how tradesmen, and anyone else for that matter, apply regulation. Dealing with them generally feels like pushing a ball up hill with a piece of wet spaghetti! It turns out that I may have to have new cables run for an electric oven. If so I can ask the electrician to run an earth wire as well. I presume that with a 200V supply the Earth is at the mid point? |
| bdunham7:
--- Quote from: Ed.Kloonk on January 19, 2021, 08:34:51 am ---If you somehow manage to connect your arms/hands to either terminal, even a portion of any isolated mains will do you in. All it takes is enough to fibrillate the heart. However, if the supply is earth bonded and protected with a RCD, chances are much higher that you wont be sitting there becoming burnt toast. --- End quote --- This has been raised before in discussions about isolation transformers. Yes, if you grab both sides, you get buzzed. And if you grab both sides of an earth-referenced RCD/GFI protected circuit, you still get buzzed but if your feet are sufficiently grounded so that additional current also goes to ground through your toes, you might get lucky and have the power shut off. This is why although I advocate the proper use of isolation transformers, I don't advocate using them in a general 'safety zone' sort of way. However, the point remains that no ground is needed for RDC/GFI, although they are a bit pointless if the power source is truly isolated and remains that way with no faults. You can dream up corner case scenarios even for ground-referenced power. Imagine grabbing both sides of a split-phase system with both hands and bare feet on concrete. The leakage to ground may be balance out and thus the GFI won't trip. |
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