Bodged Extension

[ninebob]

I went to replace a security light for my grandparents this week. It's controlled by a switch next to the back door which is located in a small extension (c1985) just used as a breakfast area.

Before I started, I noticed that the 2 "light switches" in the extension are switched FCUs. Alarms bells immediately rang in my head and sure enough, upon pulling the fuse for the lighting circuit, both breakfast room light and outside light still worked.

I've had a bit of an investigate and I'm not happy with what I've found - the entire breakfast room is what I can only describe as a "cowboy-daisy-chain-spur-bonanza".

There is one double socket in the breakfast room, which is spurred from a single socket in the kitchen (on the downstairs ring) behind the frigde. This in turn runs to the "lightswitch" for the ceiling light and then on to the switch for the security light.

I submit that this is a Very Very Bad Thing™.

I'm unsure how to go about fixing this. Reinstating the socket onto the ring is no problem (or even leaving it as a spur once the lights are disconnected from it), but the lights pose a bit more of a challenge. The extension and the kitchen it backs onto are in a single storey part of the house with a flat roof so no loft access (possibly the reason for the bodge in the first place but still no excuse IMO).

Whichever avenue I go down I have 2 lights which currently source their power at the switch, so I need some directions towards creating a system which has the loop-in there (as I beleive is the case in some new-builds).

Thanks in advance for your help guys!

(P.S. Aware of P and all that but I'm going to fix this "last year", I'm more concerned with getting the right advice and doing it safely)

 

[Adam_151]

Put the breakfast room socket onto the downstairs ring, connect the rest of the spur chain to it via a FCU with 13A fuse.

Or

Move the whole breakfast room onto its own 16A breaker

 

[plugwash]

those who think its a bad thing to put lights on a rcd may consider it sensible to put the 16A breaker on the non-rcd side of the CU and use a rcd socket.

 

[ninebob]

There is no such thing as an RCD in the whole property. The CU is an old-style 4-way fusebox, upstairs + downstairs sockets, 1 lighting circuit and not sure as yet what the other one is. It must be something because they had a shower put in a couple of years ago and an additional CU was put in (if you can call it that- this was 1998 at the earliest and it looks like a 1 fuse version of the old wylex CUs.)

I'm really quite concerned now. My grandfather is 92 years old and these "additions" to his house were done by my uncle roy, who, to coin the phrase, I wouldn't trust as far as I could throw him.

I need some sound words for 2 reasons:

1. To convince grandad that roy is bl**dy dangerous and he needs to take the advice of me and those on this forum.

2. As requested before, how can I fix the problems?

3. (In direct connection with 2.) Step by step advice would be helpful. I'm aware of "P" but between myself and my grandparents money is short and currently does not run to LABC charges. I trust you guys to advise me appropriately...

 

[Adam_151]

take spur socket off, and add it as a socket on the ring (rings are in 2.5mm² cable btw), spur off this new ring socket with 2.5mm² cable to a 13A unswitched spur, to create a fused spur, there is no limit on what can go on a fused spur, then just attach the cable that goes to the fused spurs for the lights onto this.

Ideally a cu chance is in order, but on a budget might be a problem, depending on where you are in lincolnshire (becuase thats where I am) I might be able to help, (no promises though), when I get my apprenticeship sorted, I plan to start collecting the test equipment I'll eventually need, along with other stuff, more tools, etc, so if you are happy to ignore part poo, and want some help diy-ing it, I might just be able to lend a hand.

 

[ninebob]

Great stuff, thank you. Not as tricky to put right as I originally thought then. I'm still not entirely happy that pulling the lighting fuse won't isolate some of the lights, perhaps a warning sticker on the CU is in order?

Out of interest, why a 13A fuse for the spur? Max load with outdoor (300w) and indoor (100w) lights on together is less than 2A so would a 3A fuse not be better? Both of the switched FCUs controlling the lights already have 3A fuses.

 

[Adam_151]

Maybe re-label the sockets fuse "sockets & extension light and power"

13A fuse because you are just protecting the cable from the ring socket to the switched FCUs which give protection to the lights, I can see no reason to not use 13A.

You could have the ring include the socket and both switched FCUs, but if its much more work, then its overkill

 

[BenStiller]

Wasnt Roy Rogers was it?

 

[Qedelec]

No it was Trigger from 'Only fools and horses'

 

[chrislangham]

Sir,
The first thing to do is carry out an inspection of the whole system.
The second thing you do is to carry out a test of the whole system.

The system sounds like it needs to be investigated thoroughly to me.
I am surprised that nobody suggested to you that you check the earthing before considering any modifications!
Do that first!

Check polarity
Check cable size to protection device
Check sequence of phase and neutral in your distribution board.
Check insulation
Check bonding


Hope that helps

Chris (Part P Registered)

 

[ban-all-sheds]

I can't believe how out of proportion this is all getting.

the entire breakfast room is what I can only describe as a "cowboy-daisy-chain-spur-bonanza".

[code:1]You've got

---[SO]----
|
|
|
[SO]----[SFCU]-----[SFCU]

instead of

---[SO]----[FCU]-----
|
|
|
[SO]----[SFCU]-----[SFCU][/code:1]
Hardly a "cowboy-daisy-chain-spur-bonanza".

I submit that this is a Very Very Bad Thing

No it isn't. It's not ideal, and it doesn't conform, but unlike a string of sockets on an unfused spur, I struggle to see that it's desperately unsafe.

Whichever avenue I go down I have 2 lights which currently source their power at the switch, so I need some directions towards creating a system which has the loop-in there (as I beleive is the case in some new-builds).

Why? SFCUs are DP switched, it's perfectly OK to take L & N through them to the lights - no need whatsoever to create a loop-in system.

To convince grandad that roy is bl**dy dangerous

Is he? OK - he may not know as much as he should or as he thinks, but I think you might be exaggerating again. The shower might be perfectly OK. Fuses are acceptable provided the circuit is designed with them in mind. Knowing the rating of the shower, the rating of the fuse, the size and length of the cable and its installation method would be useful, then we could tell. So he didn't fit an RCD - well, the IEE don't think they are important enough to warrant a requirement in the regs. I often think that fitting them is like wetting yourself when wearing black trousers - it gives you a nice warm feeling, but nobody really notices.
So the spur into the breakfast room is not perfect, but it's not a death trap.

Certainly you should be alert to what else Uncle Roy might have done, but I think it's overstating it to say that he is "bl**dy dangerous" or a cowboy. And if he's your grandfather's son, you need to be careful not to upset either of them with wild accusations.

As requested before, how can I fix the problems?

Chop into the wall next to the socket behind the fridge, put a 13A FCU onto the ring and move the breakfast room spur to that. Nothing else needed.

Regarding the rest of the installation, it is probably time you had a PIR done, and see what that throws up.

Sir,
The first thing to do is carry out an inspection of the whole system.

The first thing to do is to fix the problem with the breakfast room - it's a minor problem and a minor job to make it right.

The system sounds like it needs to be investigated thoroughly to me.

Probably could do with a PIR, just like the millions of other installations up and down the country that are just like it and have been working safely and successfully for decades.

I am surprised that nobody suggested to you that you check the earthing before considering any modifications!
Do that first!

You've got a thing about earthing, haven't you...
Whatever state the earthing is in, it is in, and a PIR will find that out. Moving the breakfast room spur as suggested is not a modification that will stand or fall because of the state of the earthing.

Check polarity
Check cable size to protection device
Check sequence of phase and neutral in your distribution board.
Check insulation
Check bonding


Hope that helps

Not really - it's not a complete list of tests and it's not in the right sequence...

 

[ninebob]

Wow! Detailled and useful, as ever - thanks for your time, Ban.

Will alter the spur as you have suggested this weekend, and be happy that it's now right.

Shower install doesn't look too dodgy, it's a 8kw shower wired in 10mm. The only slightly dubious thing is the choice of cable route - it's buried in plaster up the wall from the CU and clipped to the side of a joist in the loft meaning it's next to thermal insulation, personally I'd have clipped it to the top.

Point taken about a PIR - They're on a basic state pension so it will come down to how soon I can afford to pay for one. I will strive to follow this with a change of CU and therefore addition of an RCD. Hopefully that will be all that's required as the house is 1960s build and the original wiring is PVC and appears in good gondition. Despite my disregard for "P", however, I acknowledge that a CU change is beyond my current capability so I'm sure a pro will advise at the time.

Thanks guys (especially ban)!