mice

[Penners]

If I could use Photoshop, I'd post up a picture of a Kirsty Allsop cardboard cutout standing provacatively under the remains of Mr Wiggs' outhouse. But I can't, so I won't.

I will. In fact, judging by the piece of stone that she's holding it looks as though Kirstie might have... no, surely not! :shock:

 

[middi]

It may be a silly question. What has happened to the mice :wink:

 

[Penners]

Don't be boring, Middi.

That's on-topic. We don't do that!

 

[Zebra]

and I'd have to find something to do with it when I go away for the weekend......

Cue for some interesting Fred Drift:

Where does Zebra go at weekends that precludes her taking a dog?

I would have thought the more interesting question was "why does she have a van?" :lol:

Just seen this!! Stopped following the mice thread after the dog comment, sorry! Anyway, the reason it'd be awkward to take a dog at the weekends is because I go away climbing - you can leave them at the bottom of the crag but they fret and get themselves wound up in the ropes - and I have a van because I'm a Nelektrishan!*

* Not necessarily a very good one! Don't direct any electrical queries at me - there are others on here with FAR more technical understanding!

 

[LadyArowana]

Anyway, the reason it'd be awkward to take a dog at the weekends is because I go away climbing - you can leave them at the bottom of the crag but they fret and get themselves wound up in the ropes - and I have a van because I'm a Nelektrishan!*

* Not necessarily a very good one! Don't direct any electrical queries at me - there are others on here with FAR more technical understanding!

You must be OK with the electrickerey or you wouldn't still be around, guess the same goes for rock climbing. You might have been wiser to keep that hobby to yourself though. Some unscrupulous folks might try and entice you to visit their challenging ascents........ and when you get there you will find it's just a high rubble stone wall and they need the roof fixing :lol:

 

[Feltwell]

I have a van because I'm a Nelektrishan!*

Oooo, now you've done it (although actually I'd already guessed!)

So, is there any problem in my wiring the lighting in my garage through 1mm T&E rather than 1.5mm? As it's only got 360w of lighting connected to it I can't see a problem, even in conduit :wink:

I have a lot of respect for climbers, although you have to question the sanity of a few of the more extreme ones. A guy who used to work for me was a very keen climber - he'd go off to the alps for weekends, and came back one day having casually mentioned that he'd found another body that weekend. "Ohh, he'd been there for years - by the look of his kit the 1980's I'd say. He was tagged, the authorities know about him. It's quite common, I've found a few. If you cark it too far up they just strap you in place and leave you there on a ledge, it's not worth the hassle of getting you down." That, and when I received a sick note from him where the doctor said that he may need 2 toes amputating due to frostbite, made me think that maybe he was a climber due to the lift working but not going all the way to the top floor, if you get my drift!

Mind you, it's probably safer than motorbikes, which has always been my vice.

 

[MdB]

So, is there any problem in my wiring the lighting in my garage through 1mm T&E rather than 1.5mm? As it's only got 360w of lighting connected to it I can't see a problem, even in conduit :wink:

The load you currently (sorry) have connected has nothing to do with the thickness wire you use - the load can always be changed. What matters is the protection (ie. circuit breaker) on the cable to protect it in the case of overload. With a 6A MCB (which I guess you are going to use), you really want to use 1.5mm for the supply, though you may be able to get away with 1.0mm depending on how the cable is mounted and if you do the appropriate calcs.

 

[Feltwell]

Hmm, I guess due to the fact that someone else can come along later and whack more devices on the circuit / change the existing ones.

TLC have quite a nice little cable calculator on their site (there is a low voltage one on there somewhere too).

http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html

 

[Flyfisher]

I think 1.0mm2 cable is rated at 10A when encased in a wall (I'm sure Google will help confirm/correct this figure), more if just clipped to a rafter in open air, so it should be fine for Feltwell's garage, even with a 6A MCB in the consumer unit. Alternatively, I think 3A MCBs are available, which should be plenty for garage lighting and provide a large safety margin with 1.0mm2 cable.

However, I'm not really sure what the IEEE wiring regs say about such things.

 

[Feltwell]

According to TLC's little calculator, it's borderline so I'll whack 1.5mm in for the difference in cost. It's not just the thickness of the conductors, the length of cable and where it's positioned makes a difference - although there's no option on the calculator for exposed conduit, only conduit in insulation, which is over-cautious. I can't just clip it to beams - it has to be rodent resistant apparently for Building Regs, so it's going inside plastic conduit.

Some security lighting is already wired up in 1mm, but I'll just stick a 3 amp fused spur on that section. I can't get a 3amp MCB for the consumer unit I have which is a shame, as even if every possible light was on it will still pull less than 2 amps.

When it's all done I'll have to get an electrician in to check it, do the connection to the house power supply in the cellar, and sign it off for the bulding regs. I just hope they don't raise problems with what's been done in the house in the past, before my time, not conforming to current regs.

 

[Flyfisher]

I've done much the same sort of thing and had an electrician then come in to connect up to the consumer unit and certify the work. But I had discussed my plans before doing the work to be sure it would all be OK. Things such as routing of cables within walls are not really 'electrical' considerations but they certainly form part of the regulations.

In our case, the electrician also replaced a mess of old consumer units and isolating switches but was still quite happy to reconnect the old wiring.

 

[Zebra]

You might have been wiser to keep that hobby to yourself though. Some unscrupulous folks might try and entice you to visit their challenging ascents........ and when you get there you will find it's just a high rubble stone wall and they need the roof fixing :lol:

Ha ha. Not sure which is worse, that or climbing buddies trying to convince me that what my 18th Century timber framed house needs is practice holds up the stairs and across the ceiling.

Mind you, it's probably safer than motorbikes, which has always been my vice.

Yes, that was my vice until a few years ago. I had a zebra striped GPZ500, unfortunately I don't have a digital picture of it, I'll try to post it up some time. Perfect camouflage!

Re the cable calcs question, my off the top of my head opinion is it'd probably be alright, but you've made me go and get the big green book now, so now I've fessed up, I'd better answer this properly!.... on a 6A mcb, if there are no correction factors for ambient temperature, grouping or thermal insulation, which it doesn't sound like there are, then it needs to be able to carry 6A, never mind what the actual load is. Single core in conduit on a wall, 1mm can carry an astounding 13.5A!
According to the 2011 edition of the On-Site Guide.
So you'd be fine.
If the circuit was quite long you'd do a calculation for volt drop but I wouldn't worry about that in these circumstances.
Your fused spur for the security light isn't a bad idea though, so you can isolate it when the sensor goes mad, after a surprisingly short time sometimes!
No matter what the wiring is like in the rest of the house, any certification only relates to new work, so it'd be only that that they're looking at. However, in order to provide certification things like main bonding may have to be in place.
The thing though about getting an electrician to sign off DIY work, I BELIEVE that it is not strictly speaking legal. I certainly don't ever sign off other people's work.

 

[Feltwell]

Ta very much Zebra. I am aware of the "self-certification" problem, just hope I can find someone who is prepared to overlook that! I'm very reluctant to pay someone else to run a simple ring main for the sockets and radial circuit for some lights in a garage.

Re. "main bonding" - I presume this is the earthing arrangements? Should be no problem there I'd hope, as I've a nice big earth block linked straight to the incoming supply from the electricity board to earth the garage supply to.

 

[Zebra]

I think plenty of sparks do do it, so hopefully you won't have a problem.
Main bonding is a 10mm earth cable attached to your incoming services, i.e. usually your water and your gas pipe, but might also include oil pipe or anything else that comes into your house in a metal pipe. The gas should be bonded at the meter, or within 600mm of the point of entry to the building, The water should be bonded at the internal stopcock, or within 600mm of point of entry, but if your water pipe is plastic coming in, then you don't have to do it.
Whenever anything other than quite minor works are done, i.e. anything requiring a certificate, and certainly for a new circuit from the consumer unit, the box has to be ticked on the certificate saying that the bonding is done, or else the electrician has to start making creative excuses why it's not! Sometimes it can be tricky to achieve, so it's a bit of a pain. So hopefully it's already done, look for a clamp and earth cable at your gas meter and stopcock, or at least see if there are some earth cables attached to your main earth block in addition to the one that goes to your consumer unit..... Hope that helps...

 

[Feltwell]

Thanks, that is helpful.

Our earthing arrangements are that everything appears to be connected to the incoming electricity supply's earth in my cellar - as shown below:-

The gas meter is external, the pipework is connected to this earth just after it enters the house, so from what you say this is OK. The water pipe is plastic now - the old lead one is still there but is redundant, I was wondering just the other day if I should really bond this to the water pipes - what do you think? The water pipes are already bonded to the incoming electricity supply's earth, just after the stopcock. I can't see that it would do any harm, but I'm not convinced it's necessary either!

The only other service we have coming in to the house is BT, which I presume is not affected.

I've ran 10mm 3 core SWA cable from the garage underground and then through to the cellar. For the earth, I'm hoping that the earth core on the SWA plus the armour connection at the gland, connected to the earth block as shown above, will be OK.

The bit I'm definitely getting an electrician to do is the power connection in the cellar, as I really don't know what I'm doing there - and to test all my work prior to connecting it. It's a bit of a hotch-potch at the moment - the power coming in and the meter are in the cellar, the main consumer unit is elsewhere in the house - it's a fairly modern looking split load unit. Power has been tapped off in the cellar for various things, it's a bit messy but it all seems logical and safe enough - just old, and has clearly evolved rather than being planned! A connection block is attached to the meter with some tails, and then various things are connected to that. It seems a good time to tidy this up.

The white RCD on the left is recent and is where an electric shower was connected. The cream coloured fused switch is redundant and was the old garage supply (2.5mm T&E strung overhead above the drive for about 16' with no support! :roll: ). I got a mini-consumer unit, intended for connecting a shower, free from my old work - I didn't know if that could be used to replace both those, with an 80 amp RCD on the incomer and a 40 amp MCB each for the feed to the garage and a feed to the shower. If not I'll do whatever the electrician advises.

Ignore the "Danger Lift Machine", I've no idea why that is there! It was there when we moved in.

See, you shouldn't have confessed to being an electrician, we're all going to want a bit of your knowledge now :wink: :lol:

 

[Flyfisher]

I like the big red earth wire . . . at least I hope it's an earth wire. :shock: :lol:

 

[MdB]

I like the big red earth wire . . . at least I hope it's an earth wire. :shock: :lol:

and the red cored neutral wire... :roll:

 

[Feltwell]

Hmm, it's an interesting choice of colour for an earth isn't it? I'm presuming it's been like that since 1940-something, when the house first got power!

 

[d49xc]

In the part of my house that was extended in 1960, a single red sheathed cable/wire can often be seen running along under the floorboards.
This is the earth wire - presumably it was the sort of thing they did at that time.
Obviously I wouldn't like to give advice on house wiring, after all what would I know about it, I only spent 25 years working on 11500 volt 50 Hz systems and 13800volt 60Hz systems carrying many 1000's of amps..............

 

[Penners]

Our earthing arrangements are that everything appears to be connected to the incoming electricity supply's earth in my cellar

Is that what's known as Protective Multiple Earthing (PME)?