absent neutral

[Dm7192]

i was recently at a domestic job and just want to clarify something that happend, i carried out a periodic inspection and when i opend the single phase fuse board the main incomming neutral was lying disconected however the lights and all final circuits where functioning fine is this because the supply type is Tncs therefore the final circuits are gettin a neutral return via the earthing arrangments?any help would be appreciated

 

[telectrix]

from what you say, that sounds like an immediate isolation and issue of a danger notice. a picture would be a good idea.

 

[Deleted member 9648]

What was the outcome of this?.....did you disconnect or just code?

 

[Dm7192]

i reconnected neutral to main sw and continued all test results where satisfactory including ze origin and pfc, the supply authority has recently upgraded the supply cable and service head?

 

[telectrix]

is it possible that the neutral tail had just fell out due to a loose connection, or did it appear to have been taken out?

or------ could it be rogue traders have been trying to catch you out ripping the customer off for unnecessary major repair work?

 

[mickys86]

is it possible that the neutral tail had just fell out due to a loose connection, or did it appear to have been taken out?

or------ could it be rogue traders have been trying to catch you out ripping the customer off for unnecessary major repair work?

Neutral tails are quite stiff aren't they? If it was a loose connection surely it might pop out but to be actually laying disconnected??

Very peculiar

 

[mickys86]

i was recently at a domestic job and just want to clarify something that happend, i carried out a periodic inspection and when i opend the single phase fuse board the main incomming neutral was lying disconected however the lights and all final circuits where functioning fine is this because the supply type is Tncs therefore the final circuits are gettin a neutral return via the earthing arrangments?any help would be appreciated

I can't wait to get back to college to ask why this still worked!!

 

[tony mc]

Sounds like it needs a good look at as IMO your return path has been via the earth if the neutral is disconected and the power stayed what were you IR results between Neutral and Earth ?

 

[Dm7192]

it appeard to have been a loose connection but when i had the fuse board open there was no contact between the neutral tail amd the main sw yet everything was working fine, i assumed the final circuits may have been using the earth as a neutral from the sub station as it was a tncs system fro

 

[Deleted member 9648]

There would need to be a N/E connection in the final circuits for that to happen....ie- a fault. Thus the load current would pass through the fault,a very dangerous fire hazard.

 

[tony mc]

When you say the neutral was not connected and everything was working fine I would say that the return would of been via the bonding etc but that would indicate a neutral earth short as on a healthy install disconnecting the neutral should shut off the power.
If it was just loose was there any signs of burning etc?

 

[Dm7192]

I thought that myself to be honist i take it this could potentially make all conductive parts and bonding within the premisis live?

 

[Dm7192]

no there was no signs of burning as the neutral was completly out of the terminal and not connected loose

 

[Spudnik]

Even on a TNCS system, im not sure how everything would still be working with the N dissed.

 

[tony mc]

If the neutral was out then you really need to have a further look at this as a neutral to earth fault on the premeses with the main neutral disconnected is a very dangerous situation as Wirepuller has said and is a massive fire risk.

We can only go on your obsevations and tests but from your opening post alarm bells should be ringing IMO!!!!