UK Faulty Socket?!

[MadScientist]

Hi folks, new DIY member here. Currently (no pun intended ...) working on my new (old!) house; I've replaced a few sockets (in existing locations), but I've recently experienced a problem on a circuit (16A radial - this is the only socket on the radial directly from the CU, via a 30 A junction box).

When I plug an appliance in (anything, extension lead, charger), and flick the 'on' switch at the socket, power is lost to the circuit, right back to the CU. The RCD doesn't trip. If I turn the socket to the 'off' position, power is restored to the circuit. This has only just happened - been using the socket in question since I bought the house.

Any suggestions?!

Cheers!

 

[telectrix]

i'd guess at a poor connection maybe at the socket or the JB, even at the consumer unit MCB. putting it in layman's terms,you have power with no load, but as soon as you load the cicuit, the poor connection will not allow current to flow.

 

[pc1966]

How are you testing for power?

If it is a neon screwdriver then that is your first problem! They are very unreliable at testing if something is live (or much worse) is dead.

As already said, probably there is an open at the CU or the related breaker is faulty.
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These are the sort of thing you should use for checking for voltage being present:

TIS Voltage Tester

• Voltage range 12V to 690V • Automatic polarity indication • One hand operation for testing sockets• Compact pocket size design• Probe tip protection• No batteries required• Extra bright LEDs• Does not trip RCDs

www.toolstation.com

Testo 750-1 Voltage Tester

Unique design - all-around LED indicators AC/DC voltage measurements up to 690V Continuity, phase and other functions

www.tester.co.uk

Also remember it is vitally important that you check the tester is working if you are trying to prove a circuit is dead. You can buy battery powered "proving units" for that, but for most DIY use then checking it on a known live circuit first (or showing the power goes from on to off by flicking the switch) is your minimum alternative.
[automerge]1588430595[/automerge]
Another if the first not in stock:

Socket & See VIP100 Easy Voltage Tester | Toolstation

• 2 Voltage ranges - 230V and 400V AC/DC • CATIV 600V rated • No batteries required • Tips conform to HSE GS38 • Compact design to allow safe site use • 1.4m of double insulated, flexible cable

www.toolstation.com

The idea is they are simple so you can't really go wrong, and they draw a small current so a "floating" cable won't pick up enough stay voltage to show anything (as non-contact and neon screwdriver ones need very little current so can show live on an open cable near other live wires)

 

[MadScientist]

Thanks both - I've been testing with a 'dedicated pen' (not ideal, I appreciate) - I'm certainly not picking anything up from anywhere else (nothing in the vicinity), and the connections in the socket / JB are A OK (I did these, and have subsequently checked).

In terms of the idea of a poor connection somewhere, I suspect this could also result from damage to T+E within its sheath? The embedded cable might have had a lump hammer over it last week, with hindsight (I'm re-plastering the house). I've chased the cable out of the wall and can't see any damage.

Of course I haven't had the face away from the CU to check the connections are sound here - but could well be a problem with the breaker. Will consult a spark to take a look!

Cheers!

Dan

 

[telectrix]

Thanks both - I've been testing with a 'dedicated pen' (not ideal, I appreciate) - I'm certainly not picking anything up from anywhere else (nothing in the vicinity), and the connections in the socket / JB are A OK (I did these, and have subsequently checked).

In terms of the idea of a poor connection somewhere, I suspect this could also result from damage to T+E within its sheath? The embedded cable might have had a lump hammer over it last week, with hindsight (I'm re-plastering the house). I've chased the cable out of the wall and can't see any damage.

Of course I haven't had the face away from the CU to check the connections are sound here - but could well be a problem with the breaker. Will consult a spark to take a look!

Cheers!

Dan

Salford is just on the limit of my area. after covid has calmed down , I could sort it for you if you can't find anyone closer.

 

[davesparks]

Thanks both - I've been testing with a 'dedicated pen' (not ideal, I appreciate) - I'm certainly not picking anything up from anywhere else (nothing in the vicinity), and the connections in the socket / JB are A OK (I did these, and have subsequently checked).

Is it a non-contact voltage detector type?

If it is then you are almost certainly detecting a capacitively coupled voltage (aka ghost voltage) on the cable. This occurs when an unconnected cable is in closeproximity to another cable which is live.
When you plug an appliance in it connects the live conductor to the neutral which eliminates the ghost voltage.

If this is occurring at the MCB as well as the end of the circuit then it may be that the MCB has tripped without the toggle moving, or the MCB may be incorrectly fitted to the busbar.