halfords electrical cable
Stephen
My battery charger has impossibly short leads, so I'd like to crimp an
extension on. I've seen various cables for sale in Halfords, e.g.
http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_199467_langId_-1_categoryId_165562
but there's little information in store or on the web site about what
this really is.
Is there a web site that lists gauges of wire and their maximum
current for 12v dc? I've seen similar tables for mains wiring; do they
exist for automotive cables?
It would be nice to know that for 12v dc at 15A, I need a cable of x
AWG and then I could buy it from anywhere, rather than Halfords.
Thanks,
Stephen.
Mrcheerful
they are very helpful in store. Don't go too mad with the length of the
leads and make sure they are fatter than the existing ones and it will be
fine. If you have some mains cable off an old appliance like a heater or
even an old hoover that will probably be fine, just check it is at least as
big and preferably larger than the existing leads. If in doubt then just
try it, if the leads don't heat up it will be fine.
The Other Mike
That cable appears to be way too fat. If you are only going a couple
of metres you can use just about anything, an old extension cable or
lawnmower cable works just as well even if it's not the right colours.
(red and black often don't match what's used on the car anyway!)
With some old *flexible* mains cable of a good few metres the volt
drop will be next to nothing and even if you are passing 15A through
it, it won't be for long so it won't get too hot, when it drops to 3
or 4 amps you can get away with much thinner wire.
For instance look at the wires for headlamps, they pass around 6A in
an extreme environment surrounded by high temperatures and enclosed
with other wires. Battery charger wires are in free air and bundled
with other heat producing cables.
Thinner wire just gets hotter and drops slightly more volts than
thicker wire.
--
Dave Plowman (News)
Stephen <ste...@nowhere.com.invalid> wrote:
> Is there a web site that lists gauges of wire and their maximum
> current for 12v dc? I've seen similar tables for mains wiring; do they
> exist for automotive cables?
<http://www.vehicle-wiring-products.eu/VWP-onlinestore/cable/standardcable.php>
--
*Can atheists get insurance for acts of God? *
Dave Plowman da...@davenoise.co.uk London SW
To e-mail, change noise into sound.
Harry Bloomfield
> Hello,
>
> My battery charger has impossibly short leads, so I'd like to crimp an
> extension on. I've seen various cables for sale in Halfords, e.g.
> http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_199467_langId_-1_categoryId_165562
>
> but there's little information in store or on the web site about what
> this really is.
>
> Is there a web site that lists gauges of wire and their maximum
> current for 12v dc? I've seen similar tables for mains wiring; do they
> exist for automotive cables?
The amperage rating will be essentially the same - what differs is the
voltage rating, the insulation. You also need to keep in mind that the
lower the voltage, the more significant is the voltage drop.
>
> It would be nice to know that for 12v dc at 15A, I need a cable of x
> AWG and then I could buy it from anywhere, rather than Halfords.
1.5mm flex will be fine for two or three metres, so basically any of
the larger mains two core flexes - or use three core and double up on
one of the wires, rether than cut the spare one off.
I myself have my charger fixed to a roof beam in the garage. I have a
pair of brass bolts also attached to a beam, with a wire dropping down
from that with a ciggy plug on the end. That plugs into the car, then I
just clip the chargers crock clips onto the bolts - It makes it a quick
job to put the car on charge as I park it, yet means I can quickly move
the charger to the bench to charge other batteries when needed, or swap
the charger for another one.
--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk
Stephen
<rootpa...@somewhereorother.com> wrote:
>That cable appears to be way too fat.
Thanks for the help. I think the ammeter on the charger goes up to 8A,
so I just went to the next size up of cable just to be sure. I do have
some mains flex about, so I could use that this time. It might be
handy to get some of the "proper" stuff because I suppose that in cars
you only need one conductor and the chassis is the other one. If I
used flex, I'd have a wire or two flopping about unused.
Thanks,
Stephen.
Stephen
<da...@davenoise.co.uk> wrote:
>
><http://www.vehicle-wiring-products.eu/VWP-onlinestore/cable/standardcable.php>
Thanks. That's a really useful link and proves my suspicions that
Halfords were expensive.
There's a link on that page to thin wall cable, which it claims is
superior. I am a bit puzzled by this. If you look at the first cable
on each page:
standard cable: 14/0.30mm, 1mm2, 8.75amp.
thinwal* cable: 16/0.20mm, 0.5mm2, 11amp.
thin wall link=
http://www.vehicle-wiring-products.eu/VWP-onlinestore/cable/thinwall.php
So the standard cable has a 1mm^2 CSA, twice that of the thin wall
cable, and yet the thin wall version with only 0.5mm^2 CSA can carry a
higher current. Why is this? I thought the current capacity was
defined by the CSA?
Or is it that the thin wall version, as its name suggests, has thinner
insulation so doesn't heat as quickly? If the difference is insulation
thickness, why do they make standard cable with think insulation?
Normally manufacturers cut corners wherever they can! Why make a
version with more insulation than needed?
I haven't done the maths but to get the overall CSA is it a matter of
finding he CSA of one 0.2mm strands and then multiply that by the
number of them; in this case 16?
I think the prices of the thin wall were better, so is there any
reason not to buy that?
Thanks,
Stephen.
Dave Plowman (News)
Stephen <inv...@invalid.org> wrote:
> So the standard cable has a 1mm^2 CSA, twice that of the thin wall
> cable, and yet the thin wall version with only 0.5mm^2 CSA can carry a
> higher current. Why is this? I thought the current capacity was
> defined by the CSA?
> Or is it that the thin wall version, as its name suggests, has thinner
> insulation so doesn't heat as quickly? If the difference is insulation
> thickness, why do they make standard cable with think insulation?
> Normally manufacturers cut corners wherever they can! Why make a
> version with more insulation than needed?
The standard cable is obsolete - so just provided for repairs etc on older
cars. Thinwall is what you'll find on new. And yes, I'd guess the the
heating effect of a cable at maximum capacity is the primary reason. Might
also be better overload protection in modern cars - faster acting 'fuses
etc - allows a less conservative rating. It could also be the more common
use of some type of remote switching - like relays etc. So the high
current cables are shorter.
> I haven't done the maths but to get the overall CSA is it a matter of
> finding he CSA of one 0.2mm strands and then multiply that by the
> number of them; in this case 16?
> I think the prices of the thin wall were better, so is there any
> reason not to buy that?
I dunno. In a car loom, both are additionally protected for much of the
run by some form of sleeving. For your app they won't be.
The answer is I don't know which type of insulation stands up to
mechanical wear better.
--
*Filthy stinking rich -- well, two out of three ain't bad
Duncan Wood
The thinwall's normally also got a higher permissible temperature rating
for the insulation.