Have BT got their wires crossed?

[Space cat]

I was adding a new extension socket and wanted to double check the wire colours and so, to cut a long story short, I ended up on this site:

http://www.telephonesuk.co.uk/wiring_info.htm.

While I was at it I thought I'd check the voltages too and was surprized to find that mine are reversed. I checked again and there's no doubt about it; pin two is -3V and pin five is -50V relative to mains earth (fixing screw on a nearby socket).

There are two possibilities: the website is wrong or else BT crossed their wires when they fitted the master socket. Assuming the latter, should I (a) put it right myself, (b) get BT to put it right or (c) ignore it? The phones have worked on this faulty polarity for nearly twenty years.

PS: I know that some sockets have their pins numbered backwards. I've been to hell and back on that one already! The ringer is on pin three and all the phones in the house ring if I short pin three to earth.

 

[saxondale]

ignore it - they swop them left to right and back again on a whim

 

[RetiredCableGuy]

If it aint broke - don't fix it.

Although this may cause a problem if you try and get ADSL broadband.

 

[bigzed]

As Saxondale say, don't worry about it. There may be anything up to 20 joints in the feed from the Exchange to your property & all it takes is one jointer to misadvertently cross a and b leg in a joint of old and new cable colour codes and there's your cross. ( Don't ask how I know this )

Even adsl will work over these crosses without any effect. The only thing we've ever come across ( on domestic installations ) that really did need correct polarity ( to keep the battery in the unit charged ) was the old wb1900 line splitters.

 

[plugwash]

I have heared a few modems are fussy about line polarity but most aren't.

 

[Space cat]

Thanks everybody. My ADSL modem works fine, as did the dial-up one I had before. I'll ignore it.

 

[thompsk]

Remember it is an offence to alter the wiring in the bt master point under the tellegraphy and wireless act, you can plug extensions and wire into existing master points but it is illegal to alter bt wiring.

 

[bigzed]

you can plug extensions and wire into existing master points

Extensions can be plugged into any socket that BT or KC have fitted yes but only NTE5A's can be hardwired into, via the lower removable faceplate.