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#67913 - 07/21/06 01:51 AM Wire sizes
Kenbo Offline
Member
Registered: 04/07/06
Posts: 233
Loc: Scotland
Just looking at your posts here and often you mention wire gauge as 12/2 or 14/2 etc

Here in the UK we use cable like 2.5mm Twin&Earth (2.5T&E) or single cores 1.5mm.
Where the size stated is the diamiter of the copper core see here
How is cable sized where you are?
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#67914 - 07/21/06 02:30 AM Re: Wire sizes
iwire Offline
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Registered: 01/05/03
Posts: 4391
Loc: North Attleboro, MA USA
AWG or American Wire Gauge.

14 AWG is rated approx 20 amps

12 AWG is rated approx 25 amps
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#67915 - 07/21/06 03:17 AM Re: Wire sizes
C-H Offline
Member
Registered: 09/17/02
Posts: 1497
Loc: Stockholm, Sweden
I've written a little on this, with some tables:
http://www.global-electron.com/wiresizes.htm
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#67916 - 07/21/06 03:46 AM Re: Wire sizes
SteveFehr Offline
Member
Registered: 03/19/05
Posts: 1195
Loc: Chesapeake, VA
T&E looks very similar to NM cable.

Interesting- 2.5mm T&E cable is smaller than #12, yet allowed for 24A circuits, whereas the larger #12 NM is only approved to 20A?
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#67917 - 07/21/06 07:24 AM Re: Wire sizes
Radar Offline
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Registered: 04/30/04
Posts: 349
Loc: Los Angeles, CA
I seem to remember hearing somewhere that metric amps are slightly smaller than non-metric, so that accounts for the difference in ampacity values.

kidding -
Radar
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#67918 - 07/21/06 09:42 AM Re: Wire sizes
gfretwell Offline


Member
Registered: 07/20/04
Posts: 9039
Loc: Estero,Fl,usa
Actually 12 ga is good for 25a (310.16)
240.4(D) reduces that to 20a because the "small conductors" are most likely to serve receptacles where the installer has no control over what the user will plug in. They will keep plugging things in until the breaker trips, then unplug the clock. 240.4(D) forces the 80% rule on the user.
Perhaps Europeans are more dilligent about load management.
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#67919 - 07/23/06 06:45 AM Re: Wire sizes
pauluk Offline
Member
Registered: 08/11/01
Posts: 7520
Loc: Norfolk, England
Quote:
Here in the UK we use cable like 2.5mm Twin&Earth (2.5T&E) or single cores 1.5mm.
Where the size stated is the diamiter of the copper core


Not the diameter -- 1.0, 1.5, 2.5 etc. are the cross-sectional area of the conductor, in square millimeters.

The pre-metric cables (before 1970) use a size designation based on the strand diameter, e.g. 3/.036 is a conductor consisting of three strands, each of .036" diameter.

Here is a comparison of American 12/2 w/gnd Romex and British 2.5 sq. mm "T&E" cable:







Note that the ground conductor on the U.K. cable is a size smaller than the insulated conductors, 1.5 sq. mm on this 2.5 cable.

You'll note also that British T&E doesn't have any paper inside the outer sheath like Romex.


[This message has been edited by pauluk (edited 07-23-2006).]
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#67920 - 07/23/06 08:13 AM Re: Wire sizes
SteveFehr Offline
Member
Registered: 03/19/05
Posts: 1195
Loc: Chesapeake, VA
OK, so it's more like UF! Is T&E rated for wet areas?

I'm going to have to pick up some samples of metric cable next time I'm over on that side of the pond...

[This message has been edited by SteveFehr (edited 07-23-2006).]
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#67921 - 07/23/06 05:19 PM Re: Wire sizes
gfretwell Offline


Member
Registered: 07/20/04
Posts: 9039
Loc: Estero,Fl,usa
#14 is 2.08 mm2
@12 is 3.31 mm2

Per table 8
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#67922 - 07/25/06 12:11 AM Re: Wire sizes
Kenbo Offline
Member
Registered: 04/07/06
Posts: 233
Loc: Scotland
Thanks for the replys all I can say is I learned something new today.

Paul thanks for the correction. I got my vernier gauge out and measured the diameter of some T&E cores
1mm = 1.1mm
2.5mm = 1.7mm
6mm = 3.1mm
(20 years and still making asumptions tut tut)

C-H managed to follow "AWG" and "Metric" but just could not see the point of "Circular Mils" Who uses "kcmil" as a measument?
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