Connecting Neutral/Earth together

[televizora]

Re: Connecting Neutral/Earth together

Then there were others where the chassis had the N wire tied to it, making things a bit......confusing. I know it's "neutral", but shouldn't this be separate from E ?

No. There are several types of Earthing systems.
IT, TT, TN
Usually the household subscribers are connected using one of the variations of the TN, so the neutral is grounded multiple times - from the transformer itself to the electrical panel - the Neutral is connected to the Earth, thus making PEN.
Depending on the type of Earthing system we have 2 and 3 wire systems...and so on. This is why if you touch the LIVE conductor, you will be electrocuted. Because you close the circuit between the Live(230V in your case) and Neutral that is grounded, so techically you can close the circuit between any object connected to the earth with low enough resistance and the LIVE conductor itself.
There are other types of Earthing systems, where the Neutral is not grounded and it's insulated from the ground, so you have to touch both neutral and LINE to be electrocuted or where the Earth is not connected to the Neutral, so the neutral can have higher potential(voltage) than the ground.
In 2 wire systems the protective grounding works with connecting the NEUTRAL to the GROUND terminals of the power socket using a piece of wire as a bridge. Not recommended, because if the Neutral wire is damaged, the whole body of the metal appliance that has to be grounded would become with the potential of the live wire, waiting for someone to close the circuit to the ground by touching it. Because the current flows from the L to the N and via the bridge to the P to the metal body of the appliance via the grounding wire. This is why now we have 3 wire systems, residual current devices and from the apartment electrical panel there are different conductors coming to the P and N terminals of the electrical sockets, so the Earth and Ground are pseudo separated, while they still have the same potential, so the residual current breakers could work properly.
In Bulgaria we have a requirement that every new building has to have 3 wire systems from the electrical panel inside the apartments and the neutral has to be grounded inside the electrical panel, as well as we are obligated to install residual current devices in every new building(built after year 2006 if I recall correctly) But we have many old buildings with 2 wire systems, that have only L and P and the only way to keep these safe is to make sure that N is not damaged and connect P terminals to N.

[Dannyx]

Re: Connecting Neutral/Earth together

Valid point, if you want to be REALLY thorough and professional, though completely overkill for this particular purpose, since this is small remote building where only 2-3 guys will sit, so we could just walk out and into the main building or use our mobile phones in case of a fault, plus we don't ever need to call out of the company

[Curious.George]

Re: Connecting Neutral/Earth together

No telephones - it's all going to be VOIP.

You might want to rethink that; what do you do when your VoIP service (or ISP) goes down? Having a fallback PSTN connection -- AND A CONVENIENT WAY TO ACCESS IT -- can be a cheap bit of insurance.

[I have a hardwired station set in the equipment closet so I can always gain access to a PSTN line, even if the gateway goes down.]

[Dannyx]

Re: Connecting Neutral/Earth together

Why are you even running network/data cables in these?

The cables were already coming into the panel through that hole in the wall on the bottom right, so we were tasked with getting them out on the left side of the panel where a switch will go...I know, I hate it too :| Rules ? Regulations ? Codes ? What's that ?!

Where is the telephone wiring then?

No telephones - it's all going to be VOIP.

A cheap chinese energy meter with the breaker/disconnect and skinny wires AFTER it?

Oh yeah, that's another thing I'd do differently: I'd put the main breaker BEFORE the meter, not after. Again, that's how I found it and it's not ideal in many ways. I'd love to rebuild it from scratch, to make things proper, but that requires money which is unlikely to be invested, plus the "good-enough" mentality is in full effect with these guys. It's sad because I could understand not bothering when you're working on something unrelated at a client's site and all you can do is notice stuff which is not right but can't/shouldn't try to correct, but this is our own building...you'd think it'd be in our best interest to make it "nice"...

[redwire]

Re: Connecting Neutral/Earth together

Why are you even running network/data cables in these? That's against Electrical Codes here. Where is the telephone wiring then?

A cheap chinese energy meter with the breaker/disconnect and skinny wires AFTER it?
Lifting a neutral makes it go hazardous live, so there is a shock hazard if you unhook it. Notice the wiring for the energy meter's power... to shut it off...

Don't mess around cleaning up these panels. You have to learn to let go and leave prior work alone as crappy as it is. Every picture you show is due to cheapness. The neutral busbar is full with stacked connections, use the nearest rusty bolt... somebody needs to spend money on a new busbar.

[Dannyx]

Re: Connecting Neutral/Earth together

Well that's as good as we managed to get them with what we had to work with and I'd call it decent enough, if we're talking about the network cables. We purposely made them U-shaped like that so they'd be away from the power wires, plus running them straight to the hole on the left would cause them to bump into the bus bar and other wires, since the two holes are not at the same height. Sure, I would've replaced the whole panel since it's really old and pretty bent and doesn't close properly, but without the necessary funding we did the best we could for now.

[diif]

Re: Connecting Neutral/Earth together

Perhaps make those network cables nice and aesthetically pleasing before starting work correcting someone else's. Twisted, an unsightly bend in the middle and a big gap between the bunch and that stray cable.

[Dannyx]

Re: Connecting Neutral/Earth together

After a very long time since I've talked about this topic, here's another panel I got to mess around with for a new install, though here I only needed to run some network wires THROUGH it along the bottom, rather than actually do electrical work. Still, this is a new space in our company where I'll most likely move to, so being the perfectionist that I am, as you can see, it's quite messy in there and could use a little tidying by my standards.

For instance, notice that black neutral wire going from the bus-bar at the bottom to the bottom-right corner of the meter - bit of an eye-sore, isn't it ? Is it safe to disconnect just the neutral wire while you re-route it, or could that cause issues ? Sucks I can't disconnect the three red phase wires too, since they're all mangled up and I hate living with the through they're like that I'd need to find a breaker somewhere or work "live" without touching them, which is quite dangerous and not quite something I'm willing to do.

[Dannyx]

Re: Connecting Neutral/Earth together

Yeah, stealing power, especially for (large) businesses, is a dumb thing to do IMO. You'd get busted before you know it. If you reading stays the same for months on end, someone is going to catch on eventually. It's not like it's a small country cottage where you might argue that you don't indeed use any electricity at all. If you're running a 3 storey tall building, complete with elevator, there's no way in hell that thing's not using a single extra kW a month, I guarantee it, so the only thing that comes remotely close to hacking your electricity bill would be to just slightly modify the reading of the meter, so it reads less, but doesn't stop entirely....unless you're doing it legally, which involves having your own generator or wind turbine. That's not the ideal scenario in the middle of the city, is it ?

I imagine if you just cut the wire to one of those CTs, the panel can sense it (plus you'd get busted upon the first inspection which happens every few months here AFAIK). However, if you're somehow able to alter the induced magnetic field, that would make the meter read less I imagine....I dunno...guys, help me out here - I want some free kWs

EDIT: I looked up that 3g meter out of curiosity and it's apparently a Honneywell Elster AS1440

[stj]

Re: Connecting Neutral/Earth together

yes, those inductive sensing coils are a nice target!

[Dannyx]

Re: Connecting Neutral/Earth together

I reckon the "execution squad" would show up to inspect what happened when it loses connectivity Otherwise it would be WAY too easy to sabotage. Better yet, hack those CTs somehow

[stj]

Re: Connecting Neutral/Earth together

GPRS = 3G
put a staple through the antenna cable

[Dannyx]

Re: Connecting Neutral/Earth together

Here's more of my "discoveries". This one was today, though I only popped it open out of curiosity like I always do, since my workmate the electrician had already wired the extension cord for the alarm panel for me here (the lone white multicore wire). This one was a bit interesting because it had a partial makeover relatively recently, since it's rather tidy in there and the enclosure itself is new and more like what you'd see in this century, as opposed to the others I've shown you The large breaker at the bottom is new, the GPRS(?) remote-access electric meter is new (has a small antenna sticking out ), the MCBs are new, however, I can tell that the green mounting chassis is STILL the original one, dating back to when ceramic cartridge fuses were in use, as you can tell from all those mounting holes placed diagonally from one another - these would accommodate those E26 (?) sockets for the ceramic screw-in holders that held the cartridges (there's a couple of these in the other pics). From what I can tell, what they did to preserve the chassis, they cut into the old box with an angle grinder enough to make room for this cabinet, which is actually just the door and the surround, with no backing, so they could just slip it over the whole panel to cover the guts. It's a bit smaller than the original, since there's still a bit left of the old one at the top/bottom. It's like forensics, I love this stuff more and more

I believe this one also uses the "TN-C" system as they call it, whereby the earth bus bar at the bottom is also tied to the neutral star point...makes sense.

Those cylindrical drums at the bottom caught my attention. I didn't know what they were at first, but by using my brain a little I think I can safely say they're current transformers for the meter. These new "smart" meters don't have the phases running straight through them, but instead employ these "remote" CTs, clearly shown by how there's no thick wires running to the meter itself, unlike in the other 3 phase system (with the 3 ceramic fuses) where the meter DID have the three phases running directly through it. Fascinating stuff, don't know why There's something about old electric panels that fascinates me, or a combination of old and new technology like this...figuring out what used to be there and what's been removed or added or modified....makes the brain tick

[CapLeaker]

Re: Connecting Neutral/Earth together

neutral and earth are joint together only at the main fuse panel.

[stj]

Re: Connecting Neutral/Earth together

it can get complicated.
https://www.youtube.com/watch?v=AWxeb2MI37c

[petehall347]

Re: Connecting Neutral/Earth together

normally neutral and earth are together at the main panel only . am sure i read once on farms where the animals were getting shocked they tied neutral and earth together further down the line nearer to the animals drinking troughs . struck me as an odd thing to do though .

[Mario]

Re: Connecting Neutral/Earth together

Neutral is return path for electricity in a electrical system. At the panel it is bonded to earth ground.
They are at the same potential. neutral is meant to carry the unbalanced current of the live wires. 3phase or split phase. Only difference is ground wire is to carry the fault current. Its meant as a protective wire.
In canada/ USA when subpanels are wired up, we remove the bonding jumper so there is no current flowing through the grounding conductor.

https://www.youtube.com/watch?v=lI59y1h3MxU

[Dannyx]

Re: Connecting Neutral/Earth together

you should not be working on this equipment without the appropriate qualifications / certificates etc as per country

If you are working on these then as the last 'professional' to be making changes to you could well be accountable for the installation.

Totally agree there and I'm aware of the risks, not just the physical ones like something popping, but also, heaven forbid, electrocution or fires. From a purely factual standpoint, without even having to check with local laws, I'm sure both me and the company are punishable by law one way or another for doing this, even if it only involves a couple of minutes to connect three wires, even though I'm not breaking any seals (like on meters) or forcefully opening any panels - that would make it worse ! I'm actually thinking of obtaining the appropriate qualifications myself, not just for this particular purpose, since I won't be stuck wiring alarm panels that require a bit of messing with mains forever, but mostly to expound on something I might like AND be allowed to properly do it while we're at it, beyond just the practical standpoint which I think I can master on my own - unless I do something completely stupid, I think I can keep myself safe. If I feel like it REALLY goes over my head, I just stop.

We DO have an electrician "in the house" here, but he's always working on other sites, doing the same thing funnily enough, so it would involve extra time calling him up just to stick two wires in - that I agree with, if I were to be on the "corporate" side: just get your average Joe to go in there and finish the whole job, even if he's not technically allowed to (the "WHILE YOU'RE IN THERE...." approach). If I were to be on the "righteous" side, I would simply refuse to do it and flip the company off if they try to talk me into it I must admit I like working on stuff like this, especially since sometimes my OCD kicks in and I do something I'm supposed to do even LESS and that is start cleaning up other peoples' wires in there ! Couple that with the fact that it also makes you shine for finishing the job quickly and on your own, without having to ask others for help, makes me lean towards the DIY side....sorry

This was mostly a discussion about the practical aspects for mains, assuming I do it for myself at home for instance....which is probably STILL illegal if you're really a stickler for rules

[llonen]

Re: Connecting Neutral/Earth together

It is good that you are asking these kind of questions, however I would caution that since you are asking these kind of questions then you should not be working on this equipment without the appropriate qualifications / certificates etc as per country. That said from a professional point of view I would most likely condemn each of these installations, without looking into the various electrical codes and regulations for Romania in the UK at least they would not meet the codes of practise and wiring regs (now 18th edition).

If you are working on these then as the last 'professional' to be making changes to you could well be accountable for the installation. Your much better off either going back to an outlet (which you have stated you cant) in which case the safest professional advice I could offer would be to have a professional electrician install a fused spur for you.

[budm]

Re: Connecting Neutral/Earth together

US home wiring: http://www.generatorsforhomeuse.us/electrical-wiring/
http://www.esgroundingsolutions.com/...he-main-panel/