Ground wire in old apartment building. - Page 1
Forum section: electronics / general

author: macross
author_rank: Contributor
timestamp: November 11, 2019, 10:43:04 am
content: Hello, I'm renovating my newly acquired apartment and now the time has come to sort out electrical wiring. I have opened the electrical panel and found out that there is no grounding wire present. Since the apartment is located on the 5th floor I can't make my own grounding connection.I have talked with two local electricians and they both recommended me to connect my apartment ground wire to the neutral bar in the electrical box since there is no dedicated ground present in old apartment buildings. So my question would be is it safe? Or maybe I should just ignore ground wire all together? What would you guys suggest?

author: Rerouter
author_rank: Super Contributor
timestamp: November 11, 2019, 10:48:15 am
content: Which country are you in? This will influence what path is the best to take as different countries have different grounding schemesIf its Australia, then yes there should grounds joining up to neutral at the local sub-panel, however you would be best to ask one of your sparky friends for a quotation, as bringing things up to code is rarely as simple as a single wire bridge, this is the mess grandfathered standards end up leaving. as once a sparky begins work on part of it, he has to ensure any modifications or additions follow the current code for that part.I suppose an early idiot check (still assuming Australia) would be to look behind a few of the outlets to see if there is a ground wire present, sometimes you find crap like that in really old houses where you have a 3 pin socket, but the ground was never run to that socket.

author: macross
author_rank: Contributor
timestamp: November 11, 2019, 10:51:27 am
content: Quote from: Rerouter on November 11, 2019, 10:48:15 amI'm in Lithuania.

author: Rerouter
author_rank: Super Contributor
timestamp: November 11, 2019, 11:00:52 am
content: Ok, out of my area of expertise, Type F plug, so should have a ground wire of some sort behind the socket,However can't even find information about what the grounding method used over there is, I suspect it is a language barrier of sorts,

author: macross
author_rank: Contributor
timestamp: November 11, 2019, 11:05:14 am
content: Quote from: Rerouter on November 11, 2019, 11:00:52 amI have already taken out old wiring and replaced with solid core copper wire. There was only a single wire with 2 conductors coming in from the electrical panel.

author: Rerouter
author_rank: Super Contributor
timestamp: November 11, 2019, 11:13:54 am
content: The only information I can give is based on the australian wiring code,For those (as your 230/240V over there) it would be 2.5mm^2 wire for each single / double outletThe wiring would feed back to the fuse box, where you would have a brass block for active, neutral and ground, with the ground and nuetral blocks joined at only that location,In the same mix, the ground block would generally also join to some form of ground stake, or in the worst case bonded to the water pipes that then feed underground acting as a ground stake,However I would stick to just the GND-Neutal bond if your sparky freinds recommend it, as a simple test you can measure the AC voltage between Nuetral and your current floating ground, I would expect it to be about half mains but drastically drop off to single digit volts when any kind of load is applied across them such as a incandecent lamp, If the voltage does not drop, or the lamp lights, you have an issue, and it would not be safe to join.

author: macross
author_rank: Contributor
timestamp: November 11, 2019, 11:17:48 am
content: Quote from: Rerouter on November 11, 2019, 11:13:54 amYup I have used 2.5mm^2 for the outlets and 1.5mm^2 for the lighting circuits. (With separate circuit breakers of course)Thanks for your advice have a nice day

author: Ian.M
author_rank: Super Contributor
timestamp: November 11, 2019, 12:56:20 pm
content: If *you* add a ground-neutral bond, you are on the hook for the liability for any issues that arise. For your own safety you also need to make the whole apartment an equipotential bonded zone, otherwise a loose neutral anywhere below you right back to the substation feeding your block could result in a lethal voltage between your 'ground' and any true grounded objects, e.g communal TV antennae wiring or metal water pipes. However that can increase the risk to any neighbours who don't have equipotential bonding.Therefore you need a professional locally licenced electrician to do the ground bonding job, officially, with an itemised receipt, (absolutely not cash in hand / off the books), so if there are any safety related problems, the work is covered by their public liability and/or professional indemnity insurance. Also, if (god forbid) someone gets electrocuted, its *MUCH* better to be in front of the judge as a witness rather than in the dock!

author: Mikelinius
author_rank: Newbie
timestamp: November 11, 2019, 05:09:40 pm
content: In our post-soviet countries I think this is normal situation. Of course it would be better with grounding, but it would be possible probably only by renovation of the whole current instalation in the building.I recommend just connect GND an neutral in the sockets as "two local electricians and they both recommended me to connect my apartment ground wire to the neutral bar" you wrote before.

author: Gregg
author_rank: Super Contributor
timestamp: November 11, 2019, 06:19:21 pm
content: You might be able to find something like a telephone wire that you could use to pull up a new ground from a location where a true ground connection could be found. In the US a lot of older buildings had telephone wiring installed by taking the easiest path and with little support of the wires.Depending on the construction, there may be a vertical chase for plumbing that you might be able to access. If you could attach your grounding conductor to a buried metal water pipe near where it goes into the ground, it would suffice for your outlet ground terminals and your peace of mind even if it didn’t strictly meet your local code. However don’t just connect to a water pipe in your apartment for liability reasons in case of a real fault.

author: Syntax Error
author_rank: Frequent Contributor
timestamp: November 11, 2019, 10:33:10 pm
content: I think you're describing a TN-CS earthing system? Leave the upgrade to a qualified electrician. You will need to measure and have certified theearth fault loop impedanceas you want your RCD's/RCBO's to trip correctly!In the UK any appliance with a gas or water supply has to be strapped to electrical earth, which includes stainless steel sink units. Even if they are naturally earthed through the pipework. Also notify the building's owner that you have brought the electrics to standard.

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 12, 2019, 12:45:59 am
content: Quote from: Mikelinius on November 11, 2019, 05:09:40 pmSo you're just one fault away from the enclosure of devices becoming live?http://www.repairfaq.org/sam/appfaq.htm#afwysncgtn

author: Monkeh
author_rank: Super Contributor
timestamp: November 12, 2019, 01:21:27 am
content: Quote from: Syntax Error on November 11, 2019, 10:33:10 pmNo. No, no, and some more no. What is this, the 15th edition?

author: Syntax Error
author_rank: Frequent Contributor
timestamp: November 13, 2019, 12:27:43 pm
content: @Macross : For earth strap read,equi-potential earth bonding.In principle equipotential bonding is essential for the safe operation of all appliances/conductive surfaces that may have some kind of electrical grounding through anextraneousconductive part; an obvious ground path through a water heater connected to iron pipes from the basement, or a less obvious ground path, such as a copper gas pipe burried in a concrete and rebar floor. Your flat should be anequipotential zone, with all bonding inside your flat terminating at the earth bar inside your consumer unit. Ask your electrician to advise you on this. Obviously pumbing parts fitted with plastic pipes (gas, water, heating) will not have any kind of earthed connection, so would not require bonding, in the UK.P.S. I've just been told that Lithuanian (ex-Russian) wiring is "interesting and robust"

author: Monkeh
author_rank: Super Contributor
timestamp: November 13, 2019, 12:48:27 pm
content: And note that, the 15th edition being long gone, this does not involve connecting a bond to your sink..And, you not being in the UK, this may not be relevant at all, you need a suitably trained local electrician to sort this out for you.