Guess The Fault Competition

[securespark]

Hairy & Rob, you've almost got it, between you!

Here's what greeted me when I removed the CU cover:

Yes!!! The neutrals for the GF RF are in the earth busbar!!!!

The main earth to the CU was 6mm².

The Ze was 3.35 Ohms & Zs 3.71 on TN-S.

Then I realised the GF RF was on the incomer side of a 16th split board...

Hmmm. Maybe that's more than two faults, but how many contributed to the Volt Drop problem? Two, I think.

Any advance on two, anyone?

 

[RF Lighting]

I couldn't have got much closer with my guess at the earth loop

 

[ricicle]

Lost Neutral - return path through high resistance earth? (no RCD)

Ahem. (almost right - the Neutral was lost cos it wasn't there! )

 

[securespark]

Sorry, rice!

Credit where it's due. you did say that & return path through earth, which was spot on!!

Good game, good game!!

 

[hairyben]

Girls, girls.

There's only one rightfull winner here and we all know it's me.

Or, given its GFR specific, dodgy busbar/feed connection/setup?

 

[tSpark]

I think RF should get the bonus prize for his Zs answer, that was close

 

[radioredcat]

About 13 years ago i fitted some security cameras and recorder for a newsagent freind of mine and did the job on a sunday afternoon and everything was fine.
The following morning the phone rang and it was the newsagent he said there was black bars on the pictures,So i called in to have a look and sure enough two of the three cameras had hum bars on the pictures.
2 cameras were transformer fed and the other was switched mode so i got my meter out and the voltage was 208v so i told him he said it's been like that for about nine months he also said around 7-10 o clock the fluorescent lights often go out i had a look at cu/meter but it looked ok.
I then went to the neighbouring shops and they said they had similar problems and one of them was a bank and their computers kept crashing.
I told them to comlpain but i dont khow if they did
So i told him to ring the electicity board and tell them they breaking the law for suppling him with out of tolerence voltage,A few days later they came and fitted a recorder to his meter(it was a single phase) and sure enough it was below 220 most of the time.
Anyway a few weeks later they came back and connected him to a different phase and it made a slight difference as the voltage above 220 some of the time but still below the legal limit of 225.
So then they said the problem was a faulty 11KV high volltage cable and they will have to replace it which eventuallt they did and i was driving past one afternoon they had the road dug up and a big spout of water as they had hit a water main.
Anyway after that mess things were ok but it's supprising how people will put with it and not say anything.
Where i live we are supplied by 11KV overhead lines and served by a substation on poles(48 years old) but it's commonly known as powercut alley and we have had to complain loudly to united utillities,We would have short powercuts/brownouts/8-12 hour cuts and just recently every time we squally showers bang off it goes so now we have a refurbished line and a brand new substation,We have not had a powercut for 6 months it's never been known here.
I bought a ups to protect the pc as i lost a hard drive through that.
I know it's been a long story but there's another cause of low voltage


andy

 

[electronicsuk]

So, what do you think the fault might be on this TP(&N) isolator I came to the other day?!

Untitled

• electronicsuk
• 19 Nov 2008
• 1

...smelt a bit funny when I took off the covers, for some reason.

 

[Spark123]

The black insulation tape holding the wire into the crimp has become warm and dropped off?

 

[securespark]

but still below the legal limit of 225.

216-253 V, surely?

 

[securespark]

Girls, girls.

There's only one rightfull winner here and we all know it's me.

Or, given its GFR specific, dodgy busbar/feed connection/setup?

Ok, OK stop squabbling & have a virtual beer as reward...

 

[sparkyspike]

Ok, OK stop squabbling & have a virtual beer as reward...

Here you go chaps: http://www.flickr.com/photos/indy2kro/2356643811/

 

[radioredcat]

but still below the legal limit of 225.

216-253 V, surely?

At the time the nominal voltage was 240v plus or minus 6%.
One teatime we were having our tea and off goes the power for a second and the tv came back on and the video and other stuff stayed off thats when i get the meter out and find 120-160 at the sockets and then the phone rings people asking me if if the powers off,err well it's half and half.
Many years ago i got film from the video shop started to watch it and off it went 90v at the socket it was like for an hour and then it was off till the early hours.
last year we all was getting p****d off with and complained but it was starting to affect the rest of aera.
I spoke to the engineer who came out to survey the job he said it was down to faulty cables.


andy

 

[Click-Sure]

We've got a bit of a mix of old overhead and old underground lead and paper around here.

A few weeks ago some water got into an underground cable, but instead of spitting it out and healing it took one phase out and sent the others all over the place, I was working late at the time and had to abandon testing for fear of damage to my megger. They had half the road up the next day, it took 3 van loads of LV jointers to sort the mess out.

The transformer isn't too smart either, but thankfully someone wants to move it to create access for some new houses, so I'm sure Central Networks will be looking to screw a new transformer and new cabling throughout the village out of the developer!

 

[securespark]

Are your underground supplies TT, Click?

For some funny reason, of all the areas I have worked, Staffs has had by far the greatest number of u/g TT supplies.