was sent this via email. what size wire to use

[zippy656]

from www.simtekuk.co.uk‏
<TABLE cellSpacing=0 cellPadding=0><COLGROUP><COLGROUP class=ReadMsgHeaderCol2><TBODY><TR><TD class=ReadMsgHeaderCol1></TD><TD><S app="WEBIM" for="P___1473623472" email="[email protected]"></S>

Ginny Simkins </TD></TR><TR><TD></TD><TD></TD></TR><TR><TD class=ReadMsgHeaderCol1></TD><TD></TD></TR><TR><TD class=ReadMsgHeaderCol1></TD><TD></TD></TR></TBODY></TABLE>

Dear Steve

Please see below:

Sq mm Rating in Amp
0.2 1.4
0.35 3.2
0.5 1.0
0.75 14.0
1.0 16.5
1.5 21.0
2.0 25.0
2.5 29.0
3.0 33.0
4.0 39.0
6.0 50.0
10.0 70.0
16.0 110.0
25.0 170.0
35.0 240.0

Depending on load: eg 1 headlight @ 55W dividethis by lowest expected
voltage (during cranking) eg 11.5~12v, which gives a figure of 4.8 amps on a
12 v vehicle so the wire required is 0.5sqmm.

If you are using more than one piece of equipment on a wire, just add them
up and do same as above. Adjust for 24V vehicles (min @ crank is ~20v).

As far as measuring a piece of string will be fine although we like to use a
piece of 7 core trailer cable which behaves more like a loom around corners
etc.

Hope this helps

Best regards

Ginny


</PRE>

 

[Deleted account DD]

excellent stuff :thumb2

 

[ssteve]

from www.simtekuk.co.uk‏
<TABLE cellSpacing=0 cellPadding=0><COLGROUP><COLGROUP class=ReadMsgHeaderCol2><TBODY><TR><TD class=ReadMsgHeaderCol1></TD><TD><S app="WEBIM" for="P___1473623472" email="[email protected]"></S>

Ginny Simkins </TD></TR><TR><TD></TD><TD></TD></TR><TR><TD class=ReadMsgHeaderCol1></TD><TD></TD></TR><TR><TD class=ReadMsgHeaderCol1></TD><TD></TD></TR></TBODY></TABLE>

Dear Steve

Please see below:

Sq mm Rating in Amp
0.2 1.4
0.35 3.2
0.5 1.0
0.75 14.0
1.0 16.5
1.5 21.0
2.0 25.0
2.5 29.0
3.0 33.0
4.0 39.0
6.0 50.0
10.0 70.0
16.0 110.0
25.0 170.0
35.0 240.0

Depending on load: eg 1 headlight @ 55W dividethis by lowest expected
voltage (during cranking) eg 11.5~12v, which gives a figure of 4.8 amps on a
12 v vehicle so the wire required is 0.5sqmm.

If you are using more than one piece of equipment on a wire, just add them
up and do same as above. Adjust for 24V vehicles (min @ crank is ~20v).

As far as measuring a piece of string will be fine although we like to use a
piece of 7 core trailer cable which behaves more like a loom around corners
etc.

Hope this helps

Best regards

Ginny


</PRE>

11.5- 12.0 volts at cranking! a bit optimistic?

especialy when 24 volt system lost 4 volts??

ssteve

 

[extreme-4x4]

you mean someone understood all that ?

i just thought he was posting his spam mail here :nenau

 

[zippy656]

ehehehhe
i could do that, but take way to long!

 

[Deleted account DD]

well I'll :clap:clap:clap:clap:clap for zippy.

I can never find what mm wire for the power when I need to

 

[zippy656]

Thanks dave.. at least some one else found it usefull

 

[extreme-4x4]

no its good, even better you shared it

i just didnt understand it

 

[zippy656]

no its good, even better you shared it

i just didnt understand it

who said i did! :augie

 

[ocelot]

I always find it more useful to add 100% to cable size for currents up to 10A @ 12vdc, for battery/power requirements (winches etc) I use 16-18mm singles, for most other things, 4mmsq will do the job.
If really low current, 12v cig sockets for gps etc, 1.5mm flex will do the job but remember to put fuses in line.......... otherwise you could end up with burnt cable or worse...........
I work in marine electronics so well used to 12 and 24vdc systems running for 20 meters or so, if the cable is too thin, the volt drop is considerable, the thicker the cable, the better the efficiency, to a point, resistance then comes into play over very long distances..... ie, over 20m @ 12vdc

 

[zippy656]

that sounds like a good idea, always use more than you think you will,.

im after adding 3 lights sockets into the boot area, what you think i shoul duse for that then?

fuse box better than inline ones?

 

[ocelot]

depends on the current the lights draw,

w=I squared x resistance,
or
W (watts) = I (current) x V(volts) translate that into
I=W/V

Take your total wattage and divide it by the voltage.

if you're using 75 watts (3x25w 12 lamps) divide that by 12vdc to give you the current draw, which is in the 6A region, so you'd need 2.5mm cable but allowing for headroom because you'll always fit something else too....... try 4mm sq, use singles so you get more into a tight space, cable tie at 6" intervals if you can and use a fuse box, don't forget to use the right fuse for the job, if the load's 6A use a 10A fuse, again, for headroom but the fuse will blow if shorted because the battery will try to shove the current down the easiest route, ie a short cct........

 

[zippy656]

oops lighter sockets.. for fridge, orange flashing lights ( 2 x 25w ) , cb, inverter ( 150w ) phone sat nav, phone, compresser.

ok, not all at same time though, well I hope not at least, but should be ok to do so if really needed

 

[Terranosaurus]

The above specs are for modern thinwall cable (which i always use), however the stuff you are likely to come across unless you specifically buy thinwall has much lower ratings

1mm2, 8.75amp.
2mm2, 17.5amp.
3mm2, 27.5amp.
4.5mm2, 35amp.
6mm2, 42amp.
7mm2, 50amp.
8.5mm2, 60amp.
10mm2, 70amp.