no supply on part of ring main

[BrainD]

I have suddenly lost supply in all of the sockets in one of my bedrooms yet all of the other rooms on that ring main are OK. I've no idea what happened because it was only discovered when I tried to switch on a bedside lamp. Ceiling lights work OK. No main fuses were tripped and I've tried switching the mains supply switch off and on but no success.

Grateful for any help.

 

[westward10]

Sounds like a bad connection but to lose sockets on a ring final circuit you would need this to occur in two places. If you feel confident turn all power off and check the socket connections.

 

[Deleted account]

Either the circuit in question isn't a ring and its 2 radials.

Or you already had a break on the ring due to loose connection and a second break has occurred thus the section in between is not functioning, but the rest would.

Or you have a spur off the ring and a break has occurred on that section.

 

[Risteard]

Either the circuit in question isn't a ring and its 2 radials.

To be pernickety if it is fed from one protective device then it could only ever be one radial circuit even if it branches out in two directions.

 

[Deleted account]

Good point

 

[Pete999]

Easy to find out if it's a RFC

 

[westward10]

To be pernickety if it is fed from one protective device then it could only ever be one radial circuit even if it branches out in two directions.

Two radials.

 

[Deleted account]

Maybe it wasn't a good point?

 

[Toneyz]

how many sockets are not working ?,what is the fuse or mcb (protective device)ratting you it may be a loose connection with both sockets spurred of the ring (spur off a spur)depending how old the wiring is as it was allowed once.

 

[Risteard]

Two radials.

How so? It can only be one radial ciruit although it branches out in two directions from the protective device.

 

[Octopus]

We don't even know if its a ring - sure it may be on a 30A or 32A breaker but that means nothing if Dave DIY has been meddling!

 

[Octopus]

Two radials.

ONLY if they are on separate OCPD's

 

[Midwest]

Or the 'off supply' sockets, are fed by an FCU.

 

[Risteard]

Apparently you disagree westward10 but I can't see how you can reconcile your view with the definition of a circuit given in BS7671 Part 2.

 

[Midwest]

You say tomato i say tomahto

 

[BrainD]

Thanks for all your help, problem solved.

Just for the record the property is only 14 years old and we have occupied since new so the wiring is probably bang up to date and there are no spurs on this circuit. The room has 6 no double sockets and all were down.

I made sure the bedside lights were in the ON position and systematically opened each socket and I found that the bedside lights flickered when I opened particular socket and by tightening the live connection the problem was solved.

Since this socket is behind a piece of furniture and has probably only been used on the odd occasion in 14 years, what I don't understand is how the connection has worked loose in the first place?

Thanks again for your help and I would be very interested to hear what you think may have caused the problem.

 

[Pete999]

Poor workmanship

 

[BrainD]

Poor workmanship

That was my initial thought but I discounted because it's worked for 14 years. Is it possible for a loose connection to take so long surface?

 

[telectrix]

it's possible. once had one of the tails become a poor connection in a 1970's CU. was 2007 when the problem surfaced as a burnt terminal.

as for your fault. if the RFC is in fact an intact RFC, then a single loose connection would not cause the loss of any sockets apart from the one with the poor connection, as other sockets would still have a working supply from the other leg.

 

[Sharpend]

Most screw terminals will become loose over the years, this is caused through a number of factors, copper being a soft metal means it is more susceptible to expansion/contraction under load.
Alternating current (AC) by its very nature causes very small deflections in the copper.
Try for yourself with an off cut of copper cable, tighten it without squashing it (over tightened) leave for a day or so then return to it and you'll probably get an easy quarter of a turn on screw again.