Polarity Reversing At Will

[Spark123]

It isn't clear wether or not an RCD exists on the lighting circuit.

 

[EddieCurrent]

Hello,
I was thinking it was a 'dual RCD' existing board, being TT.
Thanks for pointing that out Spark123, it helps to explain my question.

Had it been a 'dual' RCD setup, there's a chance it may have tripped then ???

Or not ???
(Maybe I'm still in the dark on this one)

 

[Spark123]

Don't worry, it hasn't been confirmed one way or the other!!
TT supplies owing to the large external impedance should be protected by RCDs to the 50v rule (or 25v for some spec locations), I would have expected it to have tripped it if all was up to spec.
Metallic water mains should not be used as the electrode - they should still be main eq. bonded though.

 

[securespark]

I cannot actually remember if there was an RCD on the job, but in any case, the cpc was used as a strapper, and there was no effective earth on that circuit.

 

[ericmark]

bernardgreen if your still around can you explain use of earth rod with party line telephone?

Some builders worked on my dads house and a new consumer unit was fitted and he failed to stop RCD tripping.

On taking over the job I found a very think bare earth wire which I though the builders electrician had disconnected leaving the house with no earth. I got the supply authority to supply an earth and all converted to TN-C-S.

But when looking at this disconnected earth rod my dad had mumbled something about telephone and I thought he was just mistaken.

From what you say I wonder if it was telephone and the house had never had an earth rod connected?

Eric

 

[TicklyT]

Telephone signalling earth rods were usually a wrought iron spike with a tinned section at the top. they were usually connected up with either a 3 strand bare copper wire, or a single insulated grey or cream wire of about 1 or 1.5mm CSA.

The system worked by briefly connecting the earth to either the 'A' or 'B' leg of the telephone line, depending on which of the two customers connected to the line was calling the exchange.

For incoming calls, the ringing current path was between one leg of the line pair and earth according to which customer was called. The ringing current could cause all sorts of problems with high resistance earth paths and voltage operated breakers that were common when the system was in use.

 

[securespark]

I've just looked through & for anyone who's interested (as this thread has been resurrected), there was a 16th Ed. split board on this job.

 

[ericmark]

Thank you TicklyT I remember the old phone with button to get line and 4 digit phone numbers but by time I was wiring up things these had long gone.

I have used the old single line with earth return phones and there was a huge problem with wind.

The static in high winds completely knocked out the phones. There would be up to 5 phones on the same line and each person would be give so many rings so for Island Harbour house it was 4 turns on the handle and for Fitzroy managers house 2 turns on handle.

You should have heard the operators reaction in UK when you asked for Stanley 68 3 rings on Falkland Islands they were quite put out.

When they got the new system I have often wondered if any of the old phones were kept.

And yes the earth wire I found at my dads was then it seems for phone as it was 3 strand bare copper wire and was connected to a wrought iron spike.

Thanks Eric