OT for a sec: US wiring sources of info

[Joe R.]

At 09:11 PM 10/7/05 +0100, you wrote:
>Ethan Dicks wrote:
>> On 10/7/05, Jules Richardson <julesrichardsonuk at yahoo.co.uk> wrote:
>> 
>>>We've got a cable decoder box here that trips out the house breakers
>>>when plugged into certain outlets - irrespective of whether it's via a
>>>surge protector (probably not surprising there) or of what other loads
>>>might be sharing the same wiring to that outlet.
>>>
>>>It works fine in other outlets though, which seems like a strange
>>>problem - but I have no idea how US houses are wired (and the wiring in
>>>this place is ancient anyway!)
>> 
>> 
>> Check to see that you don't have neutral and hot swapped in certain
>> outlets. 
>
>Hmm, just had a quick look and no problems with the outlets which have 
>been causing problems - unless the whole lot's miswired where it exits 
>the breaker(s). I'll check that. And yep, it's all the old 60A 
>three-cable stuff.
>
>The plot thickens somewhat after getting some more info out of the SO 
>and doing some poking around.
>
>The problem only happens on certain outlets when the TV and cable box 
>share any of the problem outlets, and the aerial's hooked up between the 
>TV and cable box. (so I was incorrect about it *just* needing the cable 
>box plugged in to cause problems)

  I once worked in a hospital and repairing the TVs was one of my
responsibilities. One day we had a call for a TV that won't work. When we
arrived it was working fine. A little latter we had a call for the same
thing from the adjacent room. This time we checked closer. We found that
the TVs were back to back on a common wall and both TVs used the same
electrical circuit. Somewhere there was an open circuit between the AC
outlets such that the two TVs were in series so neither one would work
unless both were turned on! That's why the patients TVs were dead, one
patient would turn their set off and it would turn both of them off. The
surprising thing was that both sets worked normal when in series. Very
surprising since each one was running off 1/2 the normal voltage!

  It sounds like you might have something similar going on especially since
it seems to involve having the ariel and/or cable box hooked up. 

  Joe


>
>So it seems to be something to do with the TV and cable box having a 
>connection via the aerial lead that's causing trouble, but only when 
>they're using certain power outlets. The lead between power outlet and 
>cable box is a moulded thing and can only go one way round at either end 
>(the socket's PCB mounted at the cable box, so it can't be mis-wired 
>internally either). The TV has an integral lead, although I tried 
>swapping wires at the plug without any luck (it refuses to startup with 
>them swapped)
>
>So it'd seem like some other issue - possibly a fault within the cable 
>decoder of some description, or maybe something else which is sharing 
>the cable feed (there's a cable modem on there too, and also another TV 
>without any decoder in one of the bedrooms)
>
>Anyway, still looking for suggestions of places to ask all of this so 
>it's not on the list!
>
>cheers
>
>Jules
>