Confused about a fault with downstairs lighting, any ideas?

[jonnyb]

Hi chaps I have a query and wouldn't mind any suggestions. I've been preparing a consumer unit swap, ran the usual tests and no major worries except a low insulation resistance test on a ring. Going to swap the board tomorrow morning. Customer asked me to swap some lighting switches whilst I was there prepping today. Pulled the fuse for the downstairs lighting and this reversed the polarity on the ring sockets. Double checked and happened every time I pulled the fuse. Will investigate further in the morning but has anyone ever had this happen?

 

[Midwest]

Ehhh? I'd be sorting that before doing anything with a new CU.

 

[jonnyb]

Yeah I'm going to, just never had this particular fault before and wondered if anyone else had. As it is, I suspect I'm going to be doing a lot of fault finding tomorrow before the board is in!

 

[Midwest]

I would start at the beginning with the RFC, testing wise and locating the reason for the low IR, what values did you get?

 

[jonnyb]

Looking at my notes the ring has a L/N issue, I've written that it has various results below 2Mohms ( it seemed to vary a bit but was always too low) I was going to double check all the neons etc and retest in the morning. There is a definite issue there but I don't know how the polarity on the sockets can swap because a fuse is pulled on a separate circuit. I'm sure I'll find out but it's annoying. So long as imI not missing anything blindingly obvious.

 

[Pete999]

Looking at my notes the ring has a L/N issue, I've written that it has various results below 2Mohms ( it seemed to vary a bit but was always too low) I was going to double check all the neons etc and retest in the morning. There is a definite issue there but I don't know how the polarity on the sockets can swap because a fuse is pulled on a separate circuit. I'm sure I'll find out but it's annoying. So long as imI not missing anything blindingly obvious.

 

[buzzlightyear]

what voltage did you do for RFC, IR test ?

 

[Octopus]

Looking at my notes the ring has a L/N issue, I've written that it has various results below 2Mohms ( it seemed to vary a bit but was always too low) I was going to double check all the neons etc and retest in the morning. There is a definite issue there but I don't know how the polarity on the sockets can swap because a fuse is pulled on a separate circuit. I'm sure I'll find out but it's annoying. So long as imI not missing anything blindingly obvious.

What are you using to confirm polarity swap ?

 

[jonnyb]

Sorry pete999, I wasn't very clear that I was still on about the ir test, the end to ends were fine, I had to do it early on as a radial was in with the ring and I needed to know which was which. Didn't do the figure 8 yet though as I knew I'd be retesting it. The reason I knew the polarity changed was because the telephone had been plugged back in and it made a whiney beep. Quickly used a socket tester then unscrewed and used my volt tester. Will look more in depth in the morning.

 

[buzzlightyear]

Sorry pete999, I wasn't very clear that I was still on about the ir test, the end to ends were fine, I had to do it early on as a radial was in with the ring and I needed to know which was which. Didn't do the figure 8 yet though as I knew I'd be retesting it. The reason I knew the polarity changed was because the telephone had been plugged back in and it made a whiney beep. Quickly used a socket tester then unscrewed and used my volt tester

what the f88k ,now I am confused .

 

[jonnyb]

Initially did a l/n to e at 250 full board ir test in the vain usual hope everything would be good, then had to separate as I didn't get what I wanted haha. Tested the ring at 250 then 500, I always do it like that.

 

[westward10]

If the ring final and lighting circuit are electrically separate with no interconnection to me, this is not possible. Removing the lighting fuse should not affect the ring final.

 

[telectrix]

Sorry pete999, I wasn't very clear that I was still on about the ir test, the end to ends were fine, I had to do it early on as a radial was in with the ring and I needed to know which was which. Didn't do the figure 8 yet though as I knew I'd be retesting it. The reason I knew the polarity changed was because the telephone had been plugged back in and it made a whiney beep. Quickly used a socket tester then unscrewed and used my volt tester. Will look more in depth in the morning.

a whiney beep on a phone is not a recognised test or a clue for fault finding. start with the basics, continuity.IR. polarity. as taught.

 

[westward10]

Is polarity correct at the board.

 

[Deleted member 9648]

I'd be getting in an exorcist.