2 Lines and 4 Neutrals??

[chrisgc]

Noticed today at brothers outbuilding that the consumer unit (which is fed off the msain cu in the house) that on the lighting circuit there is 2 lives going to cb but 4 neutrals from same going to neutral bar for the light circuit?

It was only a visual look but wondered if any ideas spring to mind (I know not a lot of info to go on)?

Chris

 

[Marvo]

Could it be 2 lighting ring ccts supplied from 2 MCB's?

 

[markc123]

Picture would be handy....

You sure the neutrals havent been just bunged anywhere on the bar (like they often are) and its infact neutrals from another circuit?

 

[tbs1983]

whats it wired in? split concentric cable has 'lots of neutrals' and 'lots of earths' but only one line.

 

[chrisgc]

Picture would be handy....

You sure the neutrals havent been just bunged anywhere on the bar (like they often are) and its infact neutrals from another circuit?

Picture shows the cables from the lighting circuit.

4 neutrals going to neautral bar and then the 2 lines going to cb.

PS the crimped earths were not done by me!



For some reason the pic has been uploaded here on its side??

 

[itselectric]

I would guess from pic. that its wired in pvc conduit and lighting is going off in different directions, so instead of looping he neutrals back and forth, they have used consumer unit as a joint box.
If that makes sense.

 

[chrisgc]

I would guess from pic. that its wired in pvc conduit and lighting is going off in different directions, so instead of looping he neutrals back and forth, they have used consumer unit as a joint box.
If that makes sense.

So if doing a quick IR test (just at 250v) I should take all 4 neutrals as one and link them to the 2 lines then do it to earth that would be ok?

By the way the lighting is fluorescent tubes and I think possibly a coupke of external security floodlights are maybe connected to the same circuit.

 

[Badged01]

If you've isolated the whole board then doing an IR test L&N to E wont do any harm regardless of where the N conductors run to.

 

[chrisgc]

If you've isolated the whole board then doing an IR test L&N to E wont do any harm regardless of where the N conductors run to.

Just did that... reading come back as 0.167 mohms... not good! !

Thinking caps on now

 

[telectrix]

disconnect florries and then IR test.

 

[chrisgc]

disconnect florries and then IR test.

Disconnect as in just take fluo bulbs out of holders?

 

[telectrix]

sorry. for some reason i misread your post. thought you had florries. my bad.

 

[Badged01]

Just did that... reading come back as 0.167 mohms... not good! !

What L/E and N/E values did you get?

 

[chrisgc]

What L/E and N/E values did you get?

The same (scratch head).

Going to go back tomorrow to have another look.

 

[Badged01]

Don’t like the 4 “Neutral” set-up with just the 2 “Lives” there could be a few explanations! But a reading of 0.167 is suggesting to me something is possibly connected or mis-connected.

Fluorescent lights can effect readings depending on what ballasts, starters, capacitor etc ….. they have and whether the fitting itself is connect back to earth through the CPC. I usually just open up the unit and physically disconnect the L & N into separate blocks before testing to remove any problems.

Try that and see what you get --- on a 300 tube factory floor not quite so easy!