interference??

[peanutty]

hi guys, anybody come across this before, was in customers house as rcd tripping and lighting circuit mcb not working. when putting 2 lead voltage detector on mcb's to see if rest were ok the customer son shouted out the tv signal was getting interference,(everytime power on hes trying to find footie scores). got them to put tv on in room c/u is in and sure enough he was right. anyone noticed anything like this before. thought maybe a loose connection but wasn't, tested ring continuity, all connections in c/u, IR, etc and all ok. Any ideas?

 

[Darkwood]

Shot in the dark.... check the busbar pins on the mcb's and main switch are not on the wrong side of the screw clamp, it could be when you apply pressure to mcb you create arcing on a poor contact which can create radio interference, its more a visual check just look underneath where busbar goes into main switch and mcb's because with some brands of boards its possible to tighten up the terminals leaving the pin on the outside of the screw clamps.

 

[robsparky1975]

Make sure all is switched off when doing any work on the busbar!!!!!!!!

 

[peanutty]

Make sure all is switched off when doing any work on the busbar!!!!!!!!

thanks for the reminder!! might of forgot! would like to point out i was testing voltage when live not doing any alteration work.

 

[MarkieSparkie]

A year or so ago a friend was having similar problems and getting nowhere fast trying to solve it. He called me in to find a solution. I found two faults on the RFC 1) One end of the CPC not terminated properly, the CPC screw of at the first socket trapping the sleeving and not making contact. 2) high resistance CPC termination at an intermediate socket on the RFC, due to oxidation of the copper. This combination was was acting as an aerial, re-radiating the hash that was coming from a poorly suppressed/screened computer switch-mode power supply on the RFC, whilst the TV was plugged into the CCU socket in the kitchen.
I don't think this applies in your case Peanutty, because you say the RFC continuity is OK.

 

[peanutty]

yeah done complete test on ring r1 r2 N, everything, all ok, was a proteus board and all mcb's and rcd the same. voltage was at 250V which probably doesn't do their tv's etc much good but is in limits.
will remember your situation for possible furture fault finding. cheers.