Quick question in terms of cabling

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savage

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Hi All,

My wiring in my roof is in shambles (conduits broken, junctions without covers, the list goes on), and it is all wired with panel wire, inside conduits (or what's left of it). Honestly, I don't know how the house ever passed a COC when we purchased it, but I think the time is ripe to fix these issues finally, seeing that I am embarking on a long process of re-wiring to introduce UPS systems and what not.

I just have a few general questions please in terms of passing a COC...

Panel (house) wire must be inside conduits, Twin and Earth, does not (in your roof at least). I am therefore seriously considering to rip out all the conduits and (old) panel wire, and to rewire the wiring in my roof exclusively with Twin & Earth. However,

1) With Twin & Earth, normally, how are switches wired? Is a junction box installed on the PVC pipe running down the wall, and only the two live wires brought down to the switch, or are two entire Twin & Earth cables pulled down to the switch with connector blocks in the switch enclosure to join the Neutral and Earths? In the case of a double switch, this then means 4 Twin & Earth cables... Space becomes a premium in the 4x2 enclosures obviously. All pipes and 4x2 / 4x4 boxes are plastic, so earthing generally isn't a problem.

2) Ceiling fans? They generally just come with a pipe running up into the roof, and the wires hanging out of the pipe. Is a connector block to Twin & Earth sufficient to make the connections, or must a junction box be installed? Again, how (and what) junction box is used to attach to the metal pole from the ceiling fans? Help me out here, but as far as I know all connections that you make on an electrical cable must be enclosed in some kind of box to avoid electrical shock (and to my understanding this includes Twin & Earth too)...

3) Can someone PLEASE (with practical experience) give me the run down in terms of what EXACTLY is required in terms of 12V downlights? I've heard of people time and time again battling to get COCs in terms of 12V downlights, and eventually replacing everything with 220V downlighters JUST to get a COC. My transformers are 1) not overloaded, 2) does have overload protection, 3) properly earthed, and 4) are properly insulated power supplies. Precisely what is, and is not, permitted?

3.1) Can the power supplies lay loose in the roof, or must they be mounted (or enclosed for that matter)?
3.2) Does the fittings for the 12V downlights need to be earthed or not? Even though my existing brackets does not make provisioning for a earth
3.3) What would be the requirements in terms of cabling? They come standard with a type of Cabtyre wire (1mm), which I also don't think is sufficient. Whilst I will more than likely do the 1.5mm cabling, what are the ins and outs in terms of connecting? Is (ceramic) connector blocks sufficient to the pigtails of the light sockets?
3.4) What else are required, and why are electricians -generally- such a PITA in terms of writing out COC's for 12V lighting?
 
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savage said:
Hi All,
3) Can someone PLEASE (with practical experience) give me the run down in terms of what EXACTLY is required in terms of 12V downlights? I've heard of people time and time again battling to get COCs in terms of 12V downlights, and eventually replacing everything with 220V downlighters JUST to get a COC. My transformers are 1) not overloaded, 2) does have overload protection, 3) properly earthed, and 4) are properly insulated power supplies. Precisely what is, and is not, permitted?

3.1) Can the power supplies lay loose in the roof, or must they be mounted (or enclosed for that matter)?
3.2) Does the fittings for the 12V downlights need to be earthed or not? Even though my existing brackets does not make provisioning for a earth
3.3) What would be the requirements in terms of cabling? They come standard with a type of Cabtyre wire (1mm), which I also don't think is sufficient. Whilst I will more than likely do the 1.5mm cabling, what are the ins and outs in terms of connecting? Is (ceramic) connector blocks sufficient to the pigtails of the light sockets?
3.4) What else are required, and why are electricians -generally- such a PITA in terms of writing out COC's for 12V lighting?
Click to expand...

I presume that you talking about 50W 12V down-lighters ? I have 125+ installed.

After several long discussions with Tridonic (a German company who manufacture one of the better SABS-approved transformers) I decided to go for a transformer-per-light-fitting approach, with the transformers laying loose in the ceiling next to the light-fitting.

The pig-tails - assuming that they come from a reputable company e.g. Radiant - are adequate as-is. These were connected directly to the transformer. BTW the 12V side of the transformer doesn't have a connection for an earth.

I found Tridonic to be very helpful. When I was installing (10 years ago) their technical staff were at their factory in Cape Town. If you require expert information I would give them a call:

Tridonic SA (Pty) Ltd T/A
53-57 Yaldwyn Road, Hughes Extension, Jet Park, 1459
P. O. Box 30542
1459 Johannesburg
South Africa
Tel: +27 11 9239686
Fax: +27 11 9239684
[email protected]
www.tridonic.co.za

Cape Town
Address: Pook Road, Athlone, ATHLONE INDUSTRIA 1, 7764, South Africa
Phone:+27 21 637 8000
 
savage said:
1) With Twin & Earth, normally, how are switches wired? Is a junction box installed on the PVC pipe running down the wall, and only the two live wires brought down to the switch, or are two entire Twin & Earth cables pulled down to the switch with connector blocks in the switch enclosure to join the Neutral and Earths? In the case of a double switch, this then means 4 Twin & Earth cables... Space becomes a premium in the 4x2 enclosures obviously. All pipes and 4x2 / 4x4 boxes are plastic, so earthing generally isn't a problem.
Click to expand...
It's up to you, but as soon as you have the pvc conduit, you can introduce house wire. Join to twin and earth in junction box at the top of the PVC using connector blocks. Don't stuff twin and earth down a 20-25mm PVC conduit if you can avoid it, and if you have to, be prepared with a can of silicon spray to make it easier to feed - plastic sticks to plastic when you go around corners especially. Not so bad on a straight length. BTW, why would a double switch require 4 t+e cables anyway? Tell us more about how these switches work...

2) Ceiling fans? They generally just come with a pipe running up into the roof, and the wires hanging out of the pipe. Is a connector block to Twin & Earth sufficient to make the connections, or must a junction box be installed? Again, how (and what) junction box is used to attach to the metal pole from the ceiling fans? Help me out here, but as far as I know all connections that you make on an electrical cable must be enclosed in some kind of box to avoid electrical shock (and to my understanding this includes Twin & Earth too)...
Click to expand...
Connections get made on the other (bottom) side of the ceiling AFAIK - behind that big metal bell piece that covers everything. It's twin and earth to that side, inside the ceiling is all t+e AFAIK.

wirefanlight400.jpg
 
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savage said:
Hi All,

My wiring in my roof is in shambles (conduits broken, junctions without covers, the list goes on), and it is all wired with panel wire, inside conduits (or what's left of it). Honestly, I don't know how the house ever passed a COC when we purchased it, but I think the time is ripe to fix these issues finally, seeing that I am embarking on a long process of re-wiring to introduce UPS systems and what not.

I just have a few general questions please in terms of passing a COC...

Lots of questions I will answer what I can

Panel (house) wire must be inside conduits, Twin and Earth, does not (in your roof at least). I am therefore seriously considering to rip out all the conduits and (old) panel wire, and to rewire the wiring in my roof exclusively with Twin & Earth. However,

Correct you are but copper is pretty expensive these days so it could be quite a bit cheaper to use existing wiring.

1) With Twin & Earth, normally, how are switches wired? Is a junction box installed on the PVC pipe running down the wall, and only the two live wires brought down to the switch, or are two entire Twin & Earth cables pulled down to the switch with connector blocks in the switch enclosure to join the Neutral and Earths? In the case of a double switch, this then means 4 Twin & Earth cables... Space becomes a premium in the 4x2 enclosures obviously. All pipes and 4x2 / 4x4 boxes are plastic, so earthing generally isn't a problem.
Either way is fine and there is no standard I guess most run twin and earth down and since lighting with a 15amp breaker only needs 1.5mm wire there is room.

2) Ceiling fans? They generally just come with a pipe running up into the roof, and the wires hanging out of the pipe. Is a connector block to Twin & Earth sufficient to make the connections, or must a junction box be installed? Again, how (and what) junction box is used to attach to the metal pole from the ceiling fans? Help me out here, but as far as I know all connections that you make on an electrical cable must be enclosed in some kind of box to avoid electrical shock (and to my understanding this includes Twin & Earth too)...
If you run the twin into the fan casing you just use a chocolate block. Any connection needs to be in a juncion box you can just buy the normal plastic round ones thats used for conduit and just wire through the holes where the conduit would normally go. Since the coduit is metal you may have to earth that I am not sure here.

3) Can someone PLEASE (with practical experience) give me the run down in terms of what EXACTLY is required in terms of 12V downlights? I've heard of people time and time again battling to get COCs in terms of 12V downlights, and eventually replacing everything with 220V downlighters JUST to get a COC. My transformers are 1) not overloaded, 2) does have overload protection, 3) properly earthed, and 4) are properly insulated power supplies. Precisely what is, and is not, permitted?
Im not sure here but try your luck first and see how it goes.

3.1) Can the power supplies lay loose in the roof, or must they be mounted (or enclosed for that matter)?
3.2) Does the fittings for the 12V downlights need to be earthed or not? Even though my existing brackets does not make provisioning for a earth
3.3) What would be the requirements in terms of cabling? They come standard with a type of Cabtyre wire (1mm), which I also don't think is sufficient. Whilst I will more than likely do the 1.5mm cabling, what are the ins and outs in terms of connecting? Is (ceramic) connector blocks sufficient to the pigtails of the light sockets?
3.4) What else are required, and why are electricians -generally- such a PITA in terms of writing out COC's for 12V lighting?
Click to expand...
.
 
Arietans said:
Connections get made on the other (bottom) side of the ceiling AFAIK - behind that big metal bell piece that covers everything. It's twin and earth to that side, inside the ceiling is all t+e AFAIK.

wirefanlight400.jpg
Click to expand...

The fans that I have, the pipe runs through the ceiling boards, and the wires are exposed inside the ceiling. The cup is of course at the bottom of the ceiling - so those won't work with my fans.

As somebody stated above (and I think it is a 20mm steel pipe), a junction box on top of the steel pipe may do the trick. Will have to confirm the pipes are 20mm and that a junction box would fit, but I'll take some photos then as well in terms of how my fans look.

Junction box in terms of lights, or twin & earth down the pipes (they are all straight down) - thanks for clarifying. Since I do have some double & triple switches, I think I'll rather do a small junction box at the top of the pipe (in the ceiling) and feed normal panel wire down. At least then I only need to worry about the lives in the 2x4 boxes in the wall, instead of the mess that multiple twin & earth cables will provide.

Conduits and junctions will all be plastic though, so no earthing issues. The ceiling fans obviously will be earthed.

I am referring to the 12V / 50W downlights yes. The reason why I bring up the pig tails is that mine are (currently) connected to 1.5mm twin & earth running to the transformer (5 lights on a transfer to ensure it's not overloaded). The normal plastic connection blocks used gets hot, and melts :wtf: This then causes a short on the secondary side of the transformer, and the transformer then shuts off, killing strings of 5 or 6 lights at a time. Hence, why I brought up ceramic connection blocks which is heat resistant.

I don't think I'll go one transformer per light though, unless of course someone with solid experience can provide reasons why. As I see it, as long as the transformers are properly earthed on the primary side, and have protection, I really don't see what the fuss is about. Granted, it is IMHO, one massive big grey area currently with every sparkie basically having their own "standard" that they enforce in terms of COC. Perhaps this is a discussion to have the day that they come out to do my COC then.

Thnx for all the feedback guys, lots cleared up and lots definitely "confirmed" as far as my thoughts and suspicions went.
 
savage said:
The fans that I have, the pipe runs through the ceiling boards, and the wires are exposed inside the ceiling. The cup is of course at the bottom of the ceiling - so those won't work with my fans.

As somebody stated above (and I think it is a 20mm steel pipe), a junction box on top of the steel pipe may do the trick.
Click to expand...
That will work
Junction box in terms of lights, or twin & earth down the pipes (they are all straight down) - thanks for clarifying. Since I do have some double & triple switches, I think I'll rather do a small junction box at the top of the pipe (in the ceiling) and feed normal panel wire down.
Click to expand...
I seriously recommend 4x4 boxes in the ceiling - those 2x4s don't have much space to work with and you'll probably thank me later. Fitting those wires and chocolate blocks into a 2x4 will be tight.

Conduits and junctions will all be plastic though, so no earthing issues.
Click to expand...
Just remember that if you have switches with metal face plates or screws, those bits need to be earthed, so you will need to send an earth wire down even if it's just light switches. The exception is where you have plastic switch covers with plastic screws to fasten them on.

I have to do all of this with my late father in law's house soon... hard work, but rewarding!
Lastly, if you don't have green coated wire and want to use black or red for earth, just tape it on each connected end with green insulation tape to indicate earth - I believe that's 100% legal.

Do yourself a favour and get a simple plug tester from your electrical shop - one of those cheapies that tests earth and polarity... it's so easy to get that wrong on one or two plugs, and it will possibly save you $$ and hassle when the sparkie comes around to do your certificate.
 
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Arietans said:
Just remember that if you have switches with metal face plates or screws, those bits need to be earthed, so you will need to send an earth wire down even if it's just light switches. The exception is where you have plastic switch covers with plastic screws to fasten them on.
Click to expand...

Urgh. Steel box, plastic pipe, and plastic switch but metal screws. Earth wire it is then. Not the end of the world, but thanks - another thing that I wasn't aware of. Will most certainly pull a earth too then.

Arietans said:
Lastly, if you don't have green coated wire and want to use black or red for earth, just tape it on each connected end with green insulation tape to indicate earth - I believe that's 100% legal.
Click to expand...

Correct - 100% legal, and it's often done in 3 Phase installations too. The wire really isn't a problem for me though, it's more a matter of doing it once, and doing it correctly :)


Arietans said:
Do yourself a favour and get a simple plug tester from your electrical shop - one of those cheapies that tests earth and polarity... it's so easy to get that wrong on one or two plugs, and it will possibly save you $$ and hassle when the sparkie comes around to do your certificate.
Click to expand...

Have plenty of testers and what not. All the plugs (not the cabling) was replaced by myself +- 2 years ago and tested fine back then. You get rather fancy plugs these days though that almost instantly shows up any issues. I'm really not in the mood, nor patient enough to pull the panel wire from the underground conduits to replace the cabling. I can't see myself getting the new wires back in lol. Everything there tested fine though, so the old wire will just have to do (all up to standard and everything).

Dedi (UPS) plugs are already installed too - just waiting on the new DB panels and UPS before connecting them up.

In the mean time, I'm going to get started on the mess in the ceiling then.
 
savage said:
I am referring to the 12V / 50W downlights yes. The reason why I bring up the pig tails is that mine are (currently) connected to 1.5mm twin & earth running to the transformer (5 lights on a transfer to ensure it's not overloaded). The normal plastic connection blocks used gets hot, and melts :wtf: This then causes a short on the secondary side of the transformer, and the transformer then shuts off, killing strings of 5 or 6 lights at a time. Hence, why I brought up ceramic connection blocks which is heat resistant.

I don't think I'll go one transformer per light though, unless of course someone with solid experience can provide reasons why. As I see it, as long as the transformers are properly earthed on the primary side, and have protection, I really don't see what the fuss is about. Granted, it is IMHO, one massive big grey area currently with every sparkie basically having their own "standard" that they enforce in terms of COC. Perhaps this is a discussion to have the day that they come out to do my COC then.
Click to expand...

I was planning on using strings of lights exactly as you are doing. That was, until my electrician told me that it couldn't [legally] be done. This, in turn, led to my discussions with Tridonic, who very kindly explained the reasons why it couldn't be done and sent me a copy of the relevant pages of the wiring code.

Basically it has to do with W = A * V. Five 50W globes over 12 volts (not 220V) = 40A current draw, and that is before current drop (pretty bad in 12V systems) takes place. Which might explain your transformer / connection block problems.

So, if you look at the wiring regulations, it is not that it cannot legally be done: it is just that you will require cabling the equivalent of that used for your oven, maybe even thicker.

I might have some of the details wrong, but the overall gist of the several conversations that I had with the electronic engineers at Tridonic is that the most every string of 50W globes attached to a single transformer is in fact illegal. And, if they ever cause a fire, will invalidate the insurance.

Read the wiring code and you will find that there is no grey area involved. The fact that most electricians don't own a copy of the code is another discussion entirely :)

Any way, the bottom line was that I ended up purchasing a boot-load of metal transformers that had my car's rear suspension groaning :)
 
Ja, if you really have to do 12V downlights then single transformer/light is the way to go.
Personally, if I ever lost my sanity and decided to **** up all the ceilings in my house, I would make them all 220V with them earthed properly.
 
savage said:
In the mean time, I'm going to get started on the mess in the ceiling then.
Click to expand...
Sounds like your ceiling is in good hands - you'll probably be more compliant than 90% of houses sold these days - also don't know how my place was passed. Probably passed by Johnny Black himself.
 
Unfortunately most electricians view compliance certificates as a means of getting paid to issue a quotation ... :(
 
Drake2007 said:
Ja, if you really have to do 12V downlights then single transformer/light is the way to go.
Personally, if I ever lost my sanity and decided to **** up all the ceilings in my house, I would make them all 220V with them earthed properly.
Click to expand...

The issue that I have with the 220V downlights is that they (the lamp) get too hot, and burn out. I've seen time and time again, not only on residential properties, but commercial offices too, where the one lamp after the other gets replaced month after month after month.

My first set of 12V downlights are now I think, over 3 years old, and I haven't yet replaced one single bulb. Going 12V also IMHO is a great way to get started for longer term, 12V LED lights. Not only energy efficient, but much less wastage and heat too. Again, IMHO, I'd much rather get pinched by 12V instead of 220V up their in the ceiling :D


rrh said:
Unfortunately most electricians view compliance certificates as a means of getting paid to issue a quotation ... :(
Click to expand...

Ah-men brother. And this is what I'm afraid off too. When it ONE DAY comes to selling your house, you're most likely going to be under pressure, and in a rush. You're either in a hurry to get rid of your property so that you can move into your new house, or have a offer to purchase and now need to rush to get the paper work sorted out (COC, plumbing, etc.), and these sparkies know that. I don't now at that stage, want to be hit by a bill of R10K or R20K just to get a piece of paper before the offer to purchase expires. They milk you because they can, and that is not going to happen with this chappy.
 
savage said:
My first set of 12V downlights are now I think, over 3 years old, and I haven't yet replaced one single bulb. Going 12V also IMHO is a great way to get started for longer term, 12V LED lights. Not only energy efficient, but much less wastage and heat too. Again, IMHO, I'd much rather get pinched by 12V instead of 220V up their in the ceiling :D.
Click to expand...

You get 220V LEDs
 
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Arietans said:
My cameras run off 2x 12v, 4a transformers.. Wonder how much lighting one of those can manage? Or... One of these?
http://m.bidorbuy.co.za/mobilejquery/item/174560153/30A_12V_DC_Power_supply.html

Or something like this?
http://m.bidorbuy.co.za/mobilejquery/item/173510212/16_CAMERA_16_CHANNEL_12V_DC_POWER_SUPPLY.html

Nice and neat!

Does one need a wire and certificate to do an install like that technically?
Click to expand...

One globe: 12V x 4A = 48W.

Technically yes: in anything goes wrong as a result of your wiring your insurance will not be liable.
 
rrh said:
One globe: 12V x 4A = 48W.

Technically yes: in anything goes wrong as a result of your wiring your insurance will not be liable.
Click to expand...

Ouch... So a wiremans license is required to install a camera system then too?

Back to the calculations, if I'm hearing you, I can comfortably run 4x10w or 2x20w 12v globes on a 12v 4a psu?
 
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Arietans said:
Ouch... So a wiremans license is required to install a camera system then too?
Click to expand...

I must admit to never having thought about it, but you would need one if the 220V side of the system ended in the distribution board.

If the transformer was simply plugged into a plug socket then no.

NB: Total guess ! :)
 
rrh said:
I must admit to never having thought about it, but you would need one if the 220V side of the system ended in the distribution board.

If the transformer was simply plugged into a plug socket then no.

NB: Total guess ! :)
Click to expand...
That's my guess too which is interesting since you can just as easily burn the house down with a 30a DC supply.
 
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