Low voltage present at yellow phase??

[SYKRAPS]

Not saying that it was great in any way as I would definately do it different but I once came across a 3p board that had one of the supply cores split by a contactor to control the supply to storage heaters so very unbalanced but this could be what is going on here maybe.

 

[newtrade]

checked that. sorted mate cheers

 

[newtrade]

martinh287'

 

[Knobhead]

checked that. sorted mate cheers

And the fault was.........

 

[ipf]

And the fault was.........

Mysteriously lost....?

 

[ackbarthestar]

Agreed High Tower (i also have come across this, only once in my time though and that was in a pub/carvery)
But from my point of view i have never come across where anyone would do a Ze on a periodic inspection where any kind of fault would not of been noticed prior to that inspection (unless the yellow phase did not supply any circuits (very rare in my opinion)

I do hope the original poster posts again so we know the out come and anyone that reads this thread learns a bit more

That's a coincidence. Just done one yesterday. 3-phase intake. One phase out, nothing connected to it. so hasn't been noticed.
Strangely enough, it does appear to happen, although it was only the second time I've come across it.