Is there a recommended wire/cable for 12v in domestic installations?

cheers

Steve

"Mr Sandman" wrote in message
...
Is there a recommended wire/cable for 12v in domestic installations?

cheers

Steve

It will very much depend upon the power you wish to use. Are we talking
milliAmps or hundreds of amps?

Adam

On Tue, 5 Feb 2008 17:09:13 -0000 someone who may be "Mr Sandman"
wrote this:-

Is there a recommended wire/cable for 12v in domestic installations?

What current will it be carrying, for what distance? What sort of
heat, abrasion and so on will it be exposed to? Fixed or trailing?


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

"Mr Sandman" wrote in message
...
Is there a recommended wire/cable for 12v in domestic installations?

cheers

Steve


12 V what?
Type of cable depends on use. You wouldn't use bell wire to connect up 50
watt lights.

In article ,
Mr Sandman wrote:
Is there a recommended wire/cable for 12v in domestic installations?

Any cable will be fine for 12 volts. But if that 12 volts is at any sort
of current the cable will need to be sized to suit.

--
*If tennis elbow is painful, imagine suffering with tennis balls *

Dave Plowman London SW
To e-mail, change noise into sound.

On Tue, 5 Feb 2008 17:09:13 -0000, "Mr Sandman"
wrote:

Is there a recommended wire/cable for 12v in domestic installations?

cheers

Steve


I'm assuming you're thinking about 12v halogen lighting? Just divide
the total power by 12 to get the current and then take a look he

http://www.tlc-direct.co.uk/Figures/Tab4.6.htm

Mr Sandman wrote:

Is there a recommended wire/cable for 12v in domestic installations?

cheers

Steve

The numbers need to be run for each individual case. You need to
consider ampacity and voltage drop primarily. What are you powering
from what, at what current, over what distance? Is a regulated supply
needed?


NT

http://www.wiki.diyfaq.org.uk/index....Voltage_Wiring

"Mr Sandman" wrote in message
...
Is there a recommended wire/cable for 12v in domestic installations?

cheers

Steve



I faced this problem a while ago. I think the main consideration is that the
cable be appropriate for the current carried.
I think it would also be good if the cable is visibly not a type used for
mains wiring, to make the life of future electricians/surveyors/DIYers
easier - what do others think about this?

In an earlier contribution to this discussion,
wrote:

Mr Sandman wrote:

Is there a recommended wire/cable for 12v in domestic installations?

cheers

Steve

The numbers need to be run for each individual case. You need to
consider ampacity and voltage drop primarily. What are you powering
from what, at what current, over what distance? Is a regulated supply
needed?


NT

http://www.wiki.diyfaq.org.uk/index....Voltage_Wiring

But unless I'm mistaken, when stating the capacity of various sizes of
cable, that table assumes mains usage.

If using the cables for low voltage, the most important part of the table is
the last two columns, showing voltage drop. Whereas dropping a few volts at
240v doesn't matter too much, dropping a few volts at 12v is very
significant. This will result in the need for a much fatter cable for a
given current than is suggested by the other columns in the table.
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

Roger Mills wrote:
In an earlier contribution to this discussion,
wrote:
Mr Sandman wrote:

Is there a recommended wire/cable for 12v in domestic installations?

cheers

Steve

The numbers need to be run for each individual case. You need to
consider ampacity and voltage drop primarily. What are you powering
from what, at what current, over what distance? Is a regulated supply
needed?


NT

http://www.wiki.diyfaq.org.uk/index....Voltage_Wiring

But unless I'm mistaken, when stating the capacity of various sizes of
cable, that table assumes mains usage.

ampacity is the same regardless of voltage. But as you say...

If using the cables for low voltage, the most important part of the table is
the last two columns, showing voltage drop. Whereas dropping a few volts at
240v doesn't matter too much, dropping a few volts at 12v is very
significant. This will result in the need for a much fatter cable for a
given current than is suggested by the other columns in the table.

This is true for apps where V_drop is enough of an issue to require
upsizing the cable, but for a lot of LV apps that isnt so. Thats why
I asked about regulation.


NT

In an earlier contribution to this discussion,
wrote:

Roger Mills wrote:

If using the cables for low voltage, the most important part of the
table is the last two columns, showing voltage drop. Whereas
dropping a few volts at 240v doesn't matter too much, dropping a few
volts at 12v is very significant. This will result in the need for a
much fatter cable for a given current than is suggested by the other
columns in the table.

This is true for apps where V_drop is enough of an issue to require
upsizing the cable, but for a lot of LV apps that isnt so. Thats why
I asked about regulation.


I was actually replying to 'Bovvered' who quoted the table from the
Electricians Guide - Fifth Edition.

I would suggest that one of the most frequent domestic LV apps is 12v
halogen downlighters. If you're carrying 200 watts at 12v (4 x 50w lamps off
a single transformer), that's more than 16A. Based purely on ampacity, you
may be tempted to use 1.5mm^2 cable for this. But that would have a drop of
29mV/A/m - so you'll lose a volt for every couple of metres or so of cable -
which would be significant for anything other than very short runs.
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

On Feb 6, 6:09 am, "Mr Sandman"
wrote:
Is there a recommended wire/cable for 12v in domestic installations?

When you've decided how many amps the wiring is going to supply, make
sure that all switches can handle that current as well. Your usual 230
volt switches will probably NOT handle the current and will get very
hot.

On 07/02/2008 00:23, Matty F wrote:

When you've decided how many amps the wiring is going to supply, make
sure that all switches can handle that current as well. Your usual 230
volt switches will probably NOT handle the current and will get very
hot.

If this is an LV halogen installation it should be the 230V transformer
input at small amps being switched, not the 12V output at big amps.

On Feb 8, 11:28 am, Andy Burns wrote:
On 07/02/2008 00:23, Matty F wrote:

When you've decided how many amps the wiring is going to supply, make
sure that all switches can handle that current as well. Your usual 230
volt switches will probably NOT handle the current and will get very
hot.

If this is an LV halogen installation it should be the 230V transformer
input at small amps being switched, not the 12V output at big amps.

Sure but we haven't been told what it's for. I know a guy who put a 60
watt 12 volt light in his caravan, running off the car battery. He
wondered why the battery kept going flat and the switch (designed for
1 amp AC) just about melted. He said "but I used a 100 watt 230v light
with that switch"!

I do intend to run 12 volt wiring around my house for emergency
lighting. I'll be using small LEDs for lighting.

"ARWadworth" wrote in message
.. .

"Mr Sandman" wrote in message
...
Is there a recommended wire/cable for 12v in domestic installations?

cheers

Steve

It will very much depend upon the power you wish to use. Are we talking
milliAmps or hundreds of amps?

Adam

Sorry for the delay, forgot i posted this! The cable will need to carry 1
amp 12volts.

Steve

On Feb 9, 6:37 pm, "Mr Sandman"
wrote:
"ARWadworth" wrote in message

.. .



"Mr Sandman" wrote in message
...
Is there a recommended wire/cable for 12v in domestic installations?

cheers

Steve

It will very much depend upon the power you wish to use. Are we talking
milliAmps or hundreds of amps?

Adam

Sorry for the delay, forgot i posted this! The cable will need to carry 1
amp 12volts.

Steve

How far?
voltage drop means you might get 10V dribbling out the end of a warm
undersized conductor.

Adam

Is there a recommended wire/cable for 12v in domestic installations?

cheers

Steve

It will very much depend upon the power you wish to use. Are we talking
milliAmps or hundreds of amps?

Adam

Sorry for the delay, forgot i posted this! The cable will need to carry
1
amp 12volts.

Steve

How far?
voltage drop means you might get 10V dribbling out the end of a warm
undersized conductor.

Adam

about 2 metres

Steve