Double socket keeps failing

[Milleniumaire]

I was over at my rental replacing the failed cooker hood with a new one yesterday and took the opportunity to use my multimeter to trace the cable feeding the old extractor.

At counter level there are three sockets next to each other:

Fused Spur Switch 1 | Fused Spur Switch 2 | Double Socket

The double socket has two cables, one of which is going to Fused Spur Switch 2, the other is the supply from the circuit.

Fused Spur Switch 2 has 4 cables; IN: from Double Socket, to Fused Spur Switch 1 and a third which I believe is to the circuit. OUT: to the boiler. This Fused Spur Switch has a 3amp fuse for the boiler.

Fused Spur Switch 1 has 3 cables; IN: from Fused Spur Switch 2 and to the extractor (I determined this yesterday). OUT: To low level double socket (this is the one that failed and I originally posted about). This Fused Spur Switch has a 13 amp fuse and it was this that was replaced by the electrician who determined that the fused spur was being used by the low level double socket, into which the washing machine is plugged.

So, from what I am seeing, it would appear that Fused Spur Switch 1 is a spur, which in turn has a spur off to the low level double socket (this bit is fused), but it also feeds the extractor fan (this bit is not fused and should be).

For now, I have connected up the extractor hood to the cable that was being used by the old hood, both of which are earthed devices, so there is only live and neutral. Neither of them had plugs connected and because the old extractor wasn't connected to a fuse, neither is the new one, which concerns me.

The electrician is currently on holiday, but we have agreed to arrange to test the electrics on his return in a couple of weeks time.

I would like to have an idea what needs to be done to resolve this situation so that when I chat to him I can explain the issue and hopefully he will give me the expected solution.

Is there an easy fix for this situation or does it require cables to be re-routed?

 

[RF Lighting]

The electrician is currently on holiday

 

[JohnW2]

One might think so - but, in this case ..

... but we have agreed to arrange to test the electrics on his return in a couple of weeks time.

Kind Regards, John

 

[Milleniumaire]

Is the wiring I have described likely to cause an issue when the electrics are tested?

Obviously it needs to be sorted, but just wondering if I had NOT bothered to try to figure out what was feeding what and determined the "problem", would an electrician have found it as part of his testing?

 

[JohnW2]

Obviously it needs to be sorted, but just wondering if I had NOT bothered to try to figure out what was feeding what and determined the "problem", would an electrician have found it as part of his testing?

That's really related to the question about 'the length of a piece of string' - it all depends upon the electrician and what inspecting/testing they decided to do. However, you may be right to suspect that at least some electricians (and certainly some 'electricians') may not have discovered as much as you have.

Kind Regards, John

 

[Milleniumaire]

I guess I wouldn't expect an electrician to start looking behind all the sockets as part of the testing, so unless it somehow registers in another way it wouldn't be identified. That's probably why these things weren't identified when we had the wiring tested 4 years ago when we purchased the property.

I guess like all trades, you get good and bad tradesman and when you find a good one... The trouble is knowing when you've found a good one, especially when working in areas where "they" have the knowledge!

With decorators, joiners, brickies and even plumbers, you can see the end result, but with electricity it is all behind the scenes and until something goes wrong (if it goes wrong) you don't know they weren't very good until it is too late. At least that's my philosophy, which is why I like to understand as much as I'm capable of understanding (for a laymen) when talking to tradesmen.

 

[JohnW2]

I guess like all trades, you get good and bad tradesman and when you find a good one... The trouble is knowing when you've found a good one, especially when working in areas where "they" have the knowledge! ... With decorators, joiners, brickies and even plumbers, you can see the end result, but with electricity it is all behind the scenes and until something goes wrong (if it goes wrong) you don't know they weren't very good until it is too late. At least that's my philosophy, which is why I like to understand as much as I'm capable of understanding (for a laymen) when talking to tradesmen.

All very true.

You will very often see it being said that 'personal recommendation' is the best way to find good tradespeople but, as you say, very few members of the general public will have any way of judging the quality, or necessarily even 'safety' of work done by electricians - so they are likely to be 'recommended' on the basis of things like their tidiness, punctuality, politeness, reasonable pricing etc. - if any of those things are lacking, that does raise doubts in relation their electrical work but, even if they are faultless in relation to all those things, their electrical work could still actually be unsatisfactory, possibly even dangerous (even if 'everything seems to work').

I'm not sure that I can see any real solution to this problem for the average member of the general public. As you say, learning as much yourself about 'what to expect' is probably the best one can do - but the great majority of people won't do that.

Kind Regards, John

 

[EFLImpudence]

At counter level there are three sockets next to each other:
Fused Spur Switch 1 | Fused Spur Switch 2 | Double Socket

Two Fused Connector Units and one double socket.

The double socket has two cables, one of which is going to Fused Spur Switch 2, the other is the supply from the circuit.

Presumably the Ring Final Circuit - subject to FCU 1 details.

Fused Spur Switch 2 has 4 cables; IN: from Double Socket, to Fused Spur Switch 1 and a third which I believe is to the circuit. OUT: to the boiler. This Fused Spur Switch has a 3amp fuse for the boiler.

I make that 3 cables. Please verify.
Presumably the Ring Final Circuit - subject to FCU 1 details - and the spur to the boiler.

Fused Spur Switch 1 has 3 cables; IN: from Fused Spur Switch 2 and to the extractor (I determined this yesterday). OUT: To low level double socket (this is the one that failed and I originally posted about). This Fused Spur Switch has a 13 amp fuse and it was this that was replaced by the electrician who determined that the fused spur was being used by the low level double socket, into which the washing machine is plugged.

Are you sure?
If the Double Socket and FCU 2 are not on the Ring Final Circuit, could it be a Radial Final Circuit?
What is the rating of the Fuse/MCB in the CU for this circuit?

So, from what I am seeing, it would appear that Fused Spur Switch 1 is a spur, which in turn has a spur off to the low level double socket (this bit is fused),

Or it is a Radial Final Circuit.

but it also feeds the extractor fan

Are you sure?

(this bit is not fused and should be).

Not necessarily.

For now, I have connected up the extractor hood to the cable that was being used by the old hood, both of which are earthed devices, so there is only live and neutral. Neither of them had plugs connected and because the old extractor wasn't connected to a fuse, neither is the new one, which concerns me.

If the hood does require an earth, then obviously it should have one - many don't.

The electrician is currently on holiday, but we have agreed to arrange to test the electrics on his return in a couple of weeks time.

As we cannot see anything or test, then you will have to wait until he returns.

I would like to have an idea what needs to be done to resolve this situation so that when I chat to him I can explain the issue and hopefully he will give me the expected solution.

We cannot tell from what you say.

Is there an easy fix for this situation or does it require cables to be re-routed?

We cannot tell from what you say.

 

[plugwash]

Is the wiring I have described likely to cause an issue when the electrics are tested?

Nearly all inspection of electrical installations is done on a sample basis, it is rare for every single point to be inspected or for the installation to be thougrouly mapped.

So unless it is something that will show up on one of the standard tests, a single bodge has a very high chance of slipping past an inspection.

 

[Milleniumaire]

A picture makes it much easier to describe:

View media item 103036

....the Ring Final Circuit, could it be a Radial Final Circuit?

I'm not experienced enough to know this. The house was built in 1930, however, the neighbours believe the house has been rewired since, but it still has the original consumer unit.

What is the rating of the Fuse/MCB in the CU for this circuit?

32 amps. There is only one circuit for sockets labelled on the consumer unit. The other circuits are labelled "Upstairs Lights", "Downstairs Lights" and "Oven". There is also a separate breaker (added later I assume) for the garage.

Are you sure?

Yes, I'm sure as I disconnected the cable from Fused Spur Switch 1 and the extractor cable was no longer showing live.

If the hood does require an earth, then obviously it should have one - many don't.

The hood does NOT require an earth connection as it is Insulation class II

Not necessarily.

From the extractor hoods installation instructions:
"This device must be connected to the supply network though either a plug fused 3A or hardwired to a 2 fase spur protected by 3A fuse". ("fase" is how it is written, not my spelling mistake )
The hood came without a plug, simply a cable with live and neutral wires.

 

[EFLImpudence]

A picture makes it much easier to describe:

View media item 103036

Ok. so - connect the extractor cable to OUT and all will be well.

Yes, I'm sure as I disconnected the cable from Fused Spur Switch 1 and the extractor cable was no longer showing live.

Ok.

The hood does NOT require an earth connection as it is Insulation class II

That's alright then.
You said the hood was earthed.

From the extractor hoods installation instructions:
"This device must be connected to the supply network though either a plug fused 3A or hardwired to a 2 fase spur protected by 3A fuse". ("fase" is how it is written, not my spelling mistage )
The hood came without a plug, simply a cable with live and neutral wires.

Take no notice. Fuses are to protect cables; not appliances.

If you connect the extractor cable as I said above, then it will have a 13A fuse which will be adequate for the cable.

 

[Milleniumaire]

Your right, I meant to say "not earthed" for the extractor hood. Sorry for the confusion, my mistake.

Interesting, it never occurred to me that more than one device could be connected to the OUT connectors on the Fused Spur Switch.

I had wondered if at some point the cables in the fused spurs had been "mixed up" as Fused Spur Switch 1 would seem to be "better" used for the extractor than the lower double socket, assuming that would only ever have the washing machine plugged in using a 13 amp fuse. Having said that, I guess an appliance drawing 13 amps is likely to cause more damage to the cable than a device drawing 3 amps and therefore better to use a fuse on the appliance with the larger power requirement?

Assuming a cooker extractor fan would normally be wired up to a circuit providing power for sockets, and so would therefore be on a 32 amp mcb, why would a 3 amp fuse ever be more beneficial than a 13 amp fuse?

Sorry, for the questions, but since you mentioned in one of my other posts and above that fuses protect the cable and not the appliance, I find it more difficult to understand why different rated fuses would be used. I guess, although the fuse protects the cable it needs to be rated high enough to allow the appliance to draw the required current? So, for the washing machine, this requires upto 13 amps, whereas the extractor requires only 3 amps. Anything above 3 amps would be fine for the extractor, providing it isn't rated more than the cable can handle?

What if both the extractor and washing machine are on at the same time? Would 13 amps be high enough to avoid the fuse being blown? I guess normal working of the appliances would draw much less than 13 amps from both appliances concurrently? I suspect I've answered my own questions, but I'm keen to learn and improve my understanding.

 

[EFLImpudence]

I had wondered if at some point the cables in the fused spurs had been "mixed up" as Fused Spur Switch 1 would seem to be "better" used for the extractor than the lower double socket, assuming that would only ever have the washing machine plugged in using a 13 amp fuse. Having said that, I guess an appliance drawing 13 amps is likely to cause more damage to the cable than a device drawing 3 amps and therefore better to use a fuse on the appliance with the larger power requirement?

Possibly.
However, the washing machine is unlikely to draw 13A and the extractor is very unlikely to draw 3A.

Assuming a cooker extractor fan would normally be wired up to a circuit providing power for sockets, and so would therefore be on a 32 amp mcb, why would a 3 amp fuse ever be more beneficial than a 13 amp fuse?

It wouldn't - unless the cable was only able to cope with 3A maximum and the device was capable of drawing more than 3A.

Sorry, for the questions, but since you mentioned in one of my other posts and above that fuses protect the cable and not the appliance, I find it more difficult to understand why different rated fuses would be used.

Well, UK plugs have to have A fuse so people think the lowest rating should be fitted - you may as well but it might not be necessary.
It's like using a 10mm² cable for an inspection lamp. The cable can carry 64A and the 60W lamp draws a quarter of an Amp. Say you could get the big cable in a plug; which rating of fuse would you fit?

I guess, although the fuse protects the cable it needs to be rated high enough to allow the appliance to draw the required current? So, for the washing machine, this requires upto 13 amps, whereas the extractor requires only 3 amps. Anything above 3 amps would be fine for the extractor, providing it isn't rated more than the cable can handle?

Yes, but, as said the WM might only need 10A and the extractor 1A or less.

What if both the extractor and washing machine are on at the same time? Would 13 amps be high enough to avoid the fuse being blown?

See above.

I guess normal working of the appliances would draw much less than 13 amps from both appliances concurrently? I suspect I've answered my own questions, but I'm keen to learn and improve my understanding.

You have.

However, as you mentioned, a spur from a spur is not allowed unless BOTH are from a 13A fuse.

 

[EFLImpudence]

However, as you mentioned, a spur from a spur is not allowed unless BOTH are from a 13A fuse.

Just to clarify -

The Fused Connector Units - switched or not - are frequently mistakenly called Fused Spurs, even by manufacturers and sellers.

The Spur is the cable branched off a ring circuit, this Spur may be fused or not.

 

[Milleniumaire]

Thanks, I understand what you are saying about Fused Spurs and spurs. It has always seemed a little strange calling an FCU a fused spur, but as you say this tends to be what the laymen knows them as (including myself).

Regarding a spur that is fused (connected to an FCU), this is the first time I have come across this, but that's probably because I don't really do much with electrics. Also, all the houses I've lived in have been new builds, so haven't had botched wiring

Out of interest, is there a "better" way (I guess that would mean safer way) to wire up these sockets?