A Question About the Circuit Shown

show sumtin wud you?

Hello Anonymous, Would suggest draw hand sketch and post it…..hope you will appreciate..

"A separate earth wire accompanies the 3 core wire."

Check you local codes!

At least here in the US you can not do that. You must drive a separate earth ground for each building.

Running a ground wire between buildings creates a ground loop. That may be your root problem. BUT...

Always, always check your local building codes for how to do things or contract the work out to a licensed contractor.

The NEC does not simply require a separate ground rod for each detached structure with a sub panel. Nope.

Probably sparking because of the capacitance between line and earth. There will be an initial (possibly very high but very short duration) current when the circuit is made (by plugging in the fuse) and the capacitance charges up, if the AC isn't crossing zero at the time.

"Any explanation of this would be a help."

You have an ungrounded circuit with a phantom electrical short somewhere in the system that you can't find.

Hire a qualified electrician immediately!

I think it may be his earthing scheme that is the problem.

Me, too.

Also something a qualified electrician could resolve rather easily, if paid to do so.

These problems can't be solved, pro bono, sight unseen.

True, and there is liability involved. This is why there are licensed and bonded professionals.

It has become evident that there must be a shortage of qualified electricians in the world.

I say that because of the astronomical number of people who come here and ask the forum to fix their electrical problems for them. Usually without providing any meaningful information.

And of course expecting to get their problems explained to them and solved for free.

Either it's a shortage of electricians or an excess of cheap-ased people who want others to work for them for free.

I'll go with # 2.

Hire a qualified electrician!!!!!!!!!

I borrowed this from another "troubleshoot my unexplained, unknown electrical problems for me, and do it for free" thread that just came here.

I understand somehow the things you've been through the years. ;)

QUALIFIED. Not licensed.

Big difference.

Point is still the same.

Anons ask that their undefined problems be solved, no charge.

If the problem is all ready undefined, then, ANY answer is also undefined. So, why not just give an undefined answer to an admittedly undefined question that was posted anonymously? Grow a pair and take a stab at it!

And go change your shorts.

There are multiple problems in this thread.

1. There is the stated problem of a spark, a fuse and a radio. I will save my reply on this problem until later.
2. We have no idea where this failing power distribution circuit resides. The only hint is the nominal unit length of a meter. This implies that the circuit is outside of the United States. The location would provide at the very least a hint of the nominal power distribution voltages and frequency. I have no idea if this circuit resides inside a merchant marine vessel, multiple story apartment complex, sub-divided warehouse, factory floor, hospital, commercial aircraft, single family residence, etc.
3. There is no organization of the sparse information that is provided. This makes it very difficult to troubleshoot this circuit problem. This lack of organization of insufficient information implies the next, most critical problem of this thread.
4. The anonymous poster that started this thread has no training in electric power distribution. This conclusion makes the sparse information you do provide us suspect. While fuses are still used in critical points of all power distributions, the most common device used today is a circuit breaker, not a fuse. You do not even identify clearly where this spark happens. Is it the flash of a fuse blowing open? Is it a mild snap you hear as you screw in an Edison style fuse that leaves a tiny burn mark on the contacts? You should not be doing any work inside any power distribution panel. GET OUT! Hire an electrician to examine, troubleshoot and properly repair this circuit.

Now, as I promised, I will offer a WAG what is the problem with this circuit.

By pulling the power from this circuit while you were away you enabled something to breakdown the isolation between power and ground. This could be anything from vermin eating the insulation to water infiltrating through some insulation cracks. You may have prevented this circuit from igniting the insulation by removing power. You might have accelerated the deterioration by removing power, too. The electrician you hire should be able to identify what happened.

If your power distribution panel actually does have Edison style fuses, then don't be surprised if your electrician suggests rewiring the whole structure. Edison fuse panels have not been standard installations in the USA for over sixty years. Electrical insulation cannot last forever.

"don't be surprised if your electrician suggests rewiring the whole structure."

A competent, ethical electrician will NOT touch an old outdated system like that.

The old Ark. farm house, built in 1939, is an example. It's out in the country, but no one will even work on it.

OP is dreaming if they think a free, internet fix is coming.

"The supply of fools people who want a free ride will always outstrip the demand".

Yes, this is probably just a cheap b@$~@rd trying to get a free internet fix.

I still find it annoying, to say the least, that people have such little respect for power distribution design and standards. I do not believe people do not ask anonymously on a website how to set a broken bone but they will ask how to wire a three phase motor with single phase power. The poorly set bone may cripple one and can often be repaired later. The poorly wired circuit can easily kill a whole family.

"Dears,

I have this shooting pain in my head and there's blood flowing out of my left ear.

Please tell me how to fix this, urgently."

We (the forum) know not to try to give medical advice.

Sadly, we dispense free, lethal electrical advice many times a day.

Re Lyn post 14: "...I have this shooting pain in my head and there's blood flowing out of my left ear. Please tell me how to fix this, urgently."

How about a tourniquet around the neck! that should stop the bleeding. But beware, it needs to be released from time to time to allow blood to flow again, otherwise there is a risk of gangrene setting it. It needs to be done by an expert, or if DIY, under expert medical supervision.

But in answer to the OP, you usually get a microscopic spark even with a brand new installation - it's capacitance of the cables and nothing to worry about. On the other hand it could be due to something more sinister like rogue wiring - for which you will an expert to investigate and put right.

On the question of free advice on CR4, is there a legal liability on CR4 members, leaving us open to expensive litigation if something goes wrong when advice is acted on?

Nothing legally binding, I'm sure.

Only a moral/ethical obligation to not arm idiots with potentially lethal information that they are incapable of using safely.

I know this will not stop the forum from dispensing such information, but.......................

More than likely the white coming from the main building is the neutral and not a powered conductor.

Get a pro!!

Thank you all. I have no intention of fixing this myself. I do have a certificate in electronics and am just curious as to what possible explanation there is for this. the installation is an old one (early 50s)and needs changing and will be changed. It is in a remote area and electricians are hard to entice out there for this kind of a job. The fuses are pulled and till the problem is fixed it will stay that way so please don't think I am stupid about it. I thought of capacitance and that is why I wondered if a second earth line from the distribution board would help. The white wire is not neutral as it feeds the lighting circuit in the second building. The black is neutral and is common for both the power and lighting circuit. Until I can get an electrician interested enough I will have to do with out power in the second building. Also I do have some experience having worked as assistants to some electricians in the past so was able to trace the circuits. Wish I could get the drawing on here but I don't seem to be able to. I respect 3 things AC, DC and JC none of which I can see. Hope that puts all your minds at rest as to the safety issue.

That's a 3 phase line with Neutral and Earth and your question was again why is there a spark on new fuse when you pull it out, even if the line is without load? Right?

Conduct insulation and line to ground test with that line, down stream extending from fuse to outlets or make voltage readings Fuse point to ground as well as the outlet to ground, if you see a little discrepancy then that's causing the spark, possibly, installation was 1950, some insulation might have been degraded already its more than 60 years now.

Get basic electrical circuits theory and make the most ou of it, research on the web far more.

Remember, safety first not electrocution first, alright?

Where in the world did you get a 3 phase line with a neutral and earth from? This requires five conductors.

A split phase with neutral and ground maybe run with black, red, white and ground cabling. More often than not a black, red, white and ground wire will be used between two three way switches (a misnomer) to allow control of a lamp from two locations.

You run 3 wires into a transformer then you get a Neutral from it, if that is the case down here. I bet this raise the poor guy's level of confusion by then. =) Hey Anon, you better get an expert to see your problem, other than seeking here for a solutiom.

three phase not an option in our area

Haven't done it but I have seen wires laid directly in ground instead of in a conduit. At that age there would be insulation breakdown and that would lead to.. well I am sure you know.

Jim

Too bad you chose to post anonymously. This sounds like a no brainer for me to diagnose and explain in a way that others would follow more clearly plus sounds like a rather easy problem to correct as well. .

Oh well......

Typically the power coming in to the building is 220 volts, using 3 wires colored red, black and white.. normally are terminated as follows; Red-- L1, Black-- L2 and White as the Neutral...

Normally the measured voltage between Red and Black = (L1 and L2) = approx 230 Volts, while the voltage between White and either Red or Black = approx. 115 Volts each.

In your descriptions, it seems the Black and White wires were cross-wired? A dangerous, unsafe, shock and fire Hazard situation...

1) White wire is fused.. powered? therefore either wrong or interchanged color coding used in house wiring?

2) the Black wire (is not connected or terminated to anything? Or used as the Neutral wire instead?

To be safe you should get a licensed electrician to examine and correct the existing hazardous situation!

The OP has offered no commentary on where in the world he is... as such, your comments about the nature of the system involved and the colours used, are pretty much only true in North America.

Too true, the fact that the OP mentions metres for his distance would indicate that it is indeed not the US.

Here in Australia, although there is no legal requirement for neutral and active colours to be anything but green/green yellow, the norm for a 2Φ + N supply would be red and white for actives and black for neutral as the OP has stated, .

If the phases are 120° shifted, then the voltages would be 415v between actives and 240v active to neutral.

If the phases are 180° shifted then the voltages would be 480v between actives and 240v active to neutral.

Not quite true North of 60!

Other countries, even those in the 3rd world categories, mostly situated in Asia, do have wiring standards to follow as a minimum as stated by the NEC guidelines!

Without any wiring diagram, The posted question, although deemed to be a wiring problem may in reality turned out to be Not a real problem!

I think It is Not problem as observed by the poster in the following scenario. If an electrical appliance happened to be directly wired across the two split source, typical to a 220 volt rated or operated system. It will be normal to experience an arc even momentarily even with the unit being Off..

Draw a schematic of this layout on paper.

A simple line drawing will do.

Take a picture of the drawing and upload it to this site.

Identify the colors of each wire,show all conductors and grounds,including ground rods and bonding straps, if any.

Is the circuit 3phase,or single phase? What is the voltage of the circuit?

Where are you located?

If this is a single phase 240/120 volt circuit,why is the white being used as a hot wire?Why is the black used as a neutral?

In electronics,the black is ground,but in A/C it is always the hot wire.

By some chance,did an electronics tech wire this stuff up?

In what country are you located?

IF you provide adequate information, someone may be willing to help you,especially if you are not anonymous.

If you are getting a spark of any magnitude, you have potential to earth. To properly diagnose this I would have to put my eyes and hands on it or at least have a hand-drawn sketch. I have run into similar issues with electricity back-feeding through a light bulb that someone connected in a hot-wire loop feeding the outlet from 2 different taps in the breaker box. Luckily they connected both the receptacle taps to the same phase so it didn't go BOOM! However, I found it by grabbing the outlet and got a nice 60 volt A/C shock. Boy did it tingle. Lesson learned and I always check all taps for any voltage potential.

Good Luck

Really - you need a sketch. Otherwise we are just guessing.

Here goes my best guess. Dirt in the outlets.

I was in "electrical maintenance" for 6 years where I work, until we really got rolling on process skids so that I had a full time job designing controls. In the maintenance job, I regularly had to clean out receptacle boxes (installed by a "qualified" and licensed electrician by the way with the typical handy box full of holes) in a metal grinding area of the plant, as they would blow the circuit breaker - just about every week without cleaning. You have not described the area where your outlets are, but it doesn't take much of a conductive dust to get a current flowing between the hot terminal and the neutral on a typical receptacle at 120VAC and you are probably talking 220VAC in your case. You were "away" - did the local vermin build a nest in one? Do you have a fried rat in one? The corpse would be conductive for some time.

Don't know where in the world you are, but in the USA we use the National Electric Code published by the National Fire Protection Association. In that code using the ground as the neutral has not been allowed to an out building for many years. Separate the ground (earth) from the neutral and make sure all connections are good. -- JHF

The conclusión is obvious, you have eliminated the possibility of normal loads so you clearly have an "abnormal" Load, otherwise known as a leak!

Your clue of "static'' being picked up by a radio on a another branch circuit implies insulation breakdown. This could be cable failure (rats, damage made during installation or similar) or water ingress into one of the outlets or a junction box.

The circuit will need to be checked, point by point, to find the fault.

Remember, stay within your comfort zone with electrics as there is real danger if you get it wrong

Can't help with the answer but if you need to post a diagram there is a great free programme for schematics etc called Dia. Works a lot like Visio.

thank you all for your help. Just thought you would like some follow up. It took a while to trace the problem to an extension lead that had the active and neutral reversed on the female plug side. I rarely use the lead but have had it for over 25 + years. I can not remember if it was me or some one else who wired it up back then. I was more curious than anything as to the cause of the symptoms. I am still trying to beg borrow or even offer a large wage to get the buildings checked by an electrician. Thanks all.

Not plurry likely mate! But there would appear to be some problem with the lead ( or the socket you plugged it into) if the symptoms only appear when it is plugged in.Jim

Reversing the neutral and hot will not cause noise on the radio,but a loose,arcing connection in the cord end would do it under load.

Perhaps when you reconnected the wires you got a more solid reliable connection into the cord plug or socket and solved the problem.

Try this:Turn on the radio,and just barely make contact with any load on any

receptacle,and jiggle the connection.You will hear noise on your radio.

The noise is created by the sparking of the conductors and the arc emits a noisey magentic field.

It will be worse on AM radio than on FM,due to the signal characteristics.

Same thing happens in thunderstorms,except the effect is widespread,not local.

As I mentioned in my earlier posting the symptoms mentioned is typical for a reverse wiring polarity. As indicated in other postings, the humming noise problem is indicative of loose connection creating an open /close circuit that results into RF noise being radiated.

As in any electrical circuits, any apparent problems will only be pronounced when any actual load(s) gets connected thus creating a completed circuit!

I do not know if any one will see this post so long after I posted the original. When I made the measurements I was using a new multi meter as my old one was cactui routitus (as we say here). The new one is the type that adjusts to the voltage, the old one was not. So what looked like 112 volts AC was actually 1.12 milli volts. There never was a problem. Anyway the whole job has been sorted now. Thanks for the answers. As a matter of interest The wife just bought a new old house. I checked the roof cavity before to see the condition of the roof and wiring. All good. Checked the under flooring and all was good. I should have crawled right underneath at the time though. Ran a intercom wire under there today and found some more AC wiring that used old type wire. I guess I will need to convince the electrician to come back for another job. OH well, that's life.

One you subscribe there's no escaping new posts, glad you have the 'problem' sorted.