New to forum, Is it just me!! how have I got Voltage??

[Digi19]

Hello guys, been a voyeur of the forum for some time, just taken a u turn in career later on in life than I should, been out and done my testing and inspection and looking to join a CPS!

Iam hoping "its just me" what am i missing? Ive never seen this before!

So I'am doing a Ze at home, first time after completing my inspect and testing in order to use in preparation as part of my acceptance to a CPS. Disconnected main earth and clamped on, for some reason clamped on to the Neutral bar and not the top of the main switch and probed line in on top of main switch did the test and got a result, its at that point I'am thinking hang on how have i got a result using the Neutral bar when the main switch is off, so tested for dead between line in at the top of the main switch and the Neutral and MET with switch off and main earth disconnected and got 240v on both, so I'am then thinking fault on the neutral side of the main switch so disconnected the outgoing neutral completely from the main switch and still getting 240v top of the switch supply to Neutral Bar and to MET.

So then i disconnect all circuits, put the main earth back and the Nuetral as if it was an installation without circuits, 0v measured, so then start to add the circuits back to the board and test as before and then getting 240v potential from top of main switch to individual circuits. How?? all the time main switch off.

There is nothing else to suggest issues, its only clamping onto the Neutral Bar as part of the Ze I have discovered this.

I guess my question is how the heck can i have a 240v reading from main line in to the installation with the main earth and the Neutral disconnected how is adding circuits introducing potential. I'am lost on what to do.

Advise greatly appreciated

Cheers

Digi19

 

[SparkyChick]

Welcome to the forum

With the main switch off, have you tested for continuity between the two sets of contacts? i.e. have you checked for the correct operation of the main switch? Could be the line contacts are stuck.

Do you have a solar system? If you do, was it isolated when doing the testing?

 

[Digi19]

Wow, cheers Sparky chick for such a quick response, no other supply sources and switch operation OK and operates correctly.

Cheers

Digi 19

 

[littlespark]

Is there an isolator before the mainswitch on the board?
Gut says reverse polarity, but I’m maybe not following your sequence of testing.

 

[Silly Sausage]

Do you live in an attached house?
Have you checked the wiring in your attic?

 

[SparkyChick]

So to confirm... your readings...

Incoming L - Earth bar (with main earth disconnected) = 240v
Incoming L - Neutral bar (with neutral disconnected) = 240v

 

[Digi19]

Is there an isolator before the mainswitch on the board?
Gut says reverse polarity, but I’m maybe not following your sequence of testing.

Hi littlespark, thanks for reply. No isolator, 100amp fuse- "smart" meter-CU.

 

[Digi19]

Do you live in an attached house?
Have you checked the wiring in your attic?

Thanks Archy Strigg, Semi detached, not sure where your going with that.

 

[Digi19]

So to confirm... your readings...

Incoming L - Earth bar (with main earth disconnected) = 240v
Incoming L - Neutral bar (with neutral disconnected) = 240v

Correct.

 

[Digi19]

Is there an isolator before the mainswitch on the board?
Gut says reverse polarity, but I’m maybe not following your sequence of testing.

No isolator, polarity OK.

 

[littlespark]

I think @Archy Styrigg is implying your neighbour has connected his house to yours, to steal your leccy.
Your measuring a second supply from his house.

 

[SparkyChick]

Correct.

Providing you're bonding is good, then I would expect to see near full supply voltage between the incomer and the earth bar regardless of the state of the main earth.

I can't comment on the neutral, but it could be leakage through devices to earth.

 

[Digi19]

Ohh ok, no can't see owt. It's highley unlikely, supplies on opposite been sides of buildings I've been here a long time.

 

[snowhead]

So to confirm... your readings...

Incoming L - Earth bar (with main earth disconnected) = 240v
Incoming L - Neutral bar (with neutral disconnected) = 240v

Correct.

I read the O.P as with NO circuits connected then 0volt .
Is the voltage only present with circuits connected to the Neutral bar?
If so can you narrow it down to a single circuit and investigate?

 

[Digi19]

Providing you're bonding is good, then I would expect to see near full supply voltage between the incomer and the earth bar regardless of the state of the main earth.

I can't comment on the neutral, but it could be leakage through devices to earth.

Thanks Snowhead if I disconnect individual circuits, I get voltages from the neutral of the circuit to incomming (L) , I will test tommorow for clearer info. As per the comments

 

[gazdkw82]

I'd want to confirm the main switch is actually opening both line and neutral first.

 

[PEG]

Hi,what are you reading these voltages,with?

 

[telectrix]

Hi,what are you reading these voltages,with?

his eyes? .

 

[Digi19]

I'd want to confirm the main switch is actually opening both line and neutral first.

Confirmed ok, my first thought was fualt in switch Neutral side.

 

[Digi19]

his eyes? .

That's awesome, they haven't been calibrated in a while though and I doubt they it gs38 compliant

 

[Digi19]

Hi,what are you reading these voltages,with?

First, voltage tester when checking for dead, and then multimeter for a reading

 

[gazdkw82]

The neutral must be making a reference to earth at some point. Maybe binding through extraneous parts?

 

[PEG]

So,you confirmed isolated and safe,then placed the multimeter probes at the same point,and this is the reading we are discussing?

 

[Wilko]

I'm not sure I've understood correctly, but the N will be floating about when it's isolated. Measuring between the means of earthing and floating neutrals may give some induced voltages. These should disappear with using a 2 pole voltage probe (due to its lower internal impedance).

 

[Digi19]

The neutral must be making a reference to earth at some point. Maybe binding through extraneous parts?

Yes but I am getting the voltage with bonding removed.

 

[Digi19]

So,you confirmed isolated and safe,then placed the multimeter probes at the same point,and this is the reading we are discussing?

Isolated at main switch, 2 probe volt tester between L in and neutral bar LEDs on tester 240v. I am only getting the voltage with circuits connected. As has been suggested already is one circuit the issue and giving me return path, however if I disconnect all circuits in the property then probe L in to any disconnected neutral I am also getting between 120v and 240v ( with the cpcs disconnected as well of course)

 

[PEG]

Hi dude,you could have an installation,in a property,which is not even connected to the supply,and dependant on what equipment was in there,and what measuring instrument you chose...you could still get those voltages...

If you have two extension leads,i can give you a quick and easy way to demonstrate this.