Cross section of cable.
 

Does anyone have a favourite site, to work out the CSA required for a
piece of cable, basically I want to make up an extension to run a
circular saw (1200 W) [at 240V that is 5A] asked the chap in the local
Hardware shop for cable large enough to deal with 2 kilowatt (mmm over
speccing as usual), he said he had nothing that could deal with that
much power 2k was "cooker sized", but my kettle (e.g.) is 2200 W, so
can't trust him as far as I can throw him.
--
This post contains no hidden meanings, no implications and certainly no
hidden agendas
so it should be taken at face value. The wrong words may be used this
is due to my limitations with the English language .

soup wrote:
Does anyone have a favourite site, to work out the CSA required for
a piece of cable, basically I want to make up an extension to run a
circular saw (1200 W) [at 240V that is 5A] asked the chap in the local
Hardware shop for cable large enough to deal with 2 kilowatt (mmm over
speccing as usual), he said he had nothing that could deal with that
much power 2k was "cooker sized", but my kettle (e.g.) is 2200 W, so
can't trust him as far as I can throw him.

http://www.tlc-direct.co.uk/Technica...ltageDrop.html

HTH :-)

Dave

soup said the following on 27/09/2005 17:25:
Does anyone have a favourite site, to work out the CSA required for a
piece of cable, basically I want to make up an extension to run a
circular saw (1200 W) [at 240V that is 5A] asked the chap in the local
Hardware shop for cable large enough to deal with 2 kilowatt (mmm over
speccing as usual), he said he had nothing that could deal with that
much power 2k was "cooker sized", but my kettle (e.g.) is 2200 W, so
can't trust him as far as I can throw him.

The IEE Wiring Regulations (BS7671) provide tables of the current
carrying capacity of cables.

For your example, PVC flexible cord for extension cables to BS6500 is
covered in table 4H3A:

2kW @ 230V implies a current of 8.7 Amps. You should therefore use as a
minimum 1.0 sq mm flex, which has a rating of 10 Amps. You would need to
put a 10 Amp fuse in the plug.

However, you should consider using 1.25 sq mm flex which has a rating of
13 Amps and therefore allows you to use a standard 13 Amp fuse in your plug.

Most extension cables rated at 13A you buy in DIY sheds will be made
with 1.25 sq mm flex.

If you want to run a largish load at a long distance, you should
consider using 1.5 sq mm flex, which will have a lower voltage drop.

You could also look he

http://www.tlc-direct.co.uk/Technica...ltageDrop.html

soup wrote:

snip original question

Thanks all, will take a dawnder down to B&Q tommorow to buy 1.25 mm^2
cable, hopefully they will sell it by the metre, may even get 1.5mm^2
depending on price, not too bothered if wire is a bit thicker and less
flexible.
BTW Seem to remember there is a difference viz wire V cable V flex
does anyone know what this difference is.

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soup formulated the question :
Does anyone have a favourite site, to work out the CSA required for a
piece of cable, basically I want to make up an extension to run a
circular saw (1200 W) [at 240V that is 5A] asked the chap in the local
Hardware shop for cable large enough to deal with 2 kilowatt (mmm over
speccing as usual), he said he had nothing that could deal with that
much power 2k was "cooker sized", but my kettle (e.g.) is 2200 W, so
can't trust him as far as I can throw him.

I would suggest 1.5mm 3 core, not because of its current carrying
capacity (it would be much more than adequate), but for its robustness.
It would also help keep the voltage drop down to a low value.

--

Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.org

Soup pretended :
Thanks all, will take a dawnder down to B&Q tommorow to buy 1.25 mm^2 cable,

If the cable is to be fitted with a 13amp socket at the end, then it
_must_ be 3 core.

--

Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.org

Soup wrote on 27/09/2005 :
BTW Seem to remember there is a difference viz wire V cable V flex
does anyone know what this difference is.

If you mean solid core, versus flexible core, then you _must_ use
flexible otherwise known as flex.

--

Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.org

Soup wrote:
soup wrote:

snip original question

Thanks all, will take a dawnder down to B&Q tommorow to buy 1.25 mm^2
cable, hopefully they will sell it by the metre, may even get 1.5mm^2
depending on price, not too bothered if wire is a bit thicker and less
flexible.
BTW Seem to remember there is a difference viz wire V cable V flex
does anyone know what this difference is.

They don't sell it by the metre any more. Why not just get a made-up
extension cable or cable reel? They will be labelled with the current
rating - so never mind about cable thicknesses - eg for at Screwfix, for
£4.25 (10A):
http://www.screwfix.com/app/sfd/cat/...46713&id=13941

The capacity you need is really not at all 'special'; it's not as if
you're trying to run a 3kW fire or a toaster at the end of a 100m
extension or something!

David

Lobster wrote:
Soup wrote:
soup wrote:

snip original question

Thanks all, will take a dawnder down to B&Q tommorow to buy 1.25
mm^2 cable, hopefully they will sell it by the metre, may even get
1.5mm^2 depending on price, not too bothered if wire is a bit
thicker and less flexible.
BTW Seem to remember there is a difference viz wire V cable V flex
does anyone know what this difference is.

They don't sell it by the metre any more. Why not just get a made-up
extension cable or cable reel? They will be labelled with the current
rating - so never mind about cable thicknesses - eg for at Screwfix,
for £4.25 (10A):

http://www.screwfix.com/app/sfd/cat/...46713&id=13941

The capacity you need is really not at all 'special'; it's not as if
you're trying to run a 3kW fire or a toaster at the end of a 100m
extension or something!


Thing is I have a "plug" and a "trailing socket" which I was going to
make up into an extension with cable from a hedge trimmer but noticed in
time that the cable from the hedge trimmer was only two core and an
earth wire was required as well, so thought I will just nip to the local
hard ware and get a piece of cable that started the whole "cooker size"
thing, which really confused me, after all I was told 2kW was lots of
power and yet lots of the appliances in my house were there or
thereabouts. Will need to rethink now I have found out B&Q don't sell
cable by the metre . Mmm may well get cable from local shop but without
listening to any of the words coming out of his mouth.
--
This post contains no hidden meanings, no implications and certainly no
hidden agendas so it should be taken at face value. The wrong words
may be used this is due to my limitations with the English language .

Does anyone have a favourite site, to work out the CSA required for a
piece of cable, basically I want to make up an extension to run a
circular saw

Depending on how much length you want to pick up, IIRC you might also
come across a reactive resistivity if you leave the majority of it
coiled up. Can lead to the cable warming up, and in extreme cases,
melting the insulation.

Its been a while since I played with the stuff in the "real world"
though, so my theory is now very patchy :-(

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Colin Wilson wrote:
Depending on how much length you want to pick up, IIRC you might also
come across a reactive resistivity if you leave the majority of it
coiled up. Can lead to the cable warming up, and in extreme cases,
melting the insulation.

Since "doing" resistance,inductance and capacitance at college (a long
time ago) have always uncoiled any extension, but as has been pointed
out this is hardly at the cutting edge, I was just looking for the size
of a bit of cable to "cobble-up" an extension to chuck in a box beside a
circular saw .
--
This post contains no hidden meanings, no implications and certainly no
hidden agendas so it should be taken at face value. The wrong words
may be used this is due to my limitations with the English language .

"Colin Wilson" wrote in message
t...

Depending on how much length you want to pick up, IIRC you might also
come across a reactive resistivity if you leave the majority of it
coiled up. Can lead to the cable warming up, and in extreme cases,
melting the insulation.

Hmmm.

The reason it gets hot when it's wound up is because it can't cool-down
because it's all in a lump. It's nothing to do with inductance. To a first
approximation, it would be exactly the same with DC.

The unwound cable is wasting almost exactly the same amount of heat, but
it's not getting so hot because it's more spaced out.

Its been a while since I played with the stuff in the "real world"
though, so my theory is now very patchy :-(

Yes. But you're right that you shouldn't use wound-up extension cables
except for very light loads.

Will

In article ,
"soup" writes:

Does anyone have a favourite site, to work out the CSA required for a
piece of cable, basically I want to make up an extension to run a

General guideline for extension leads fused at 13A...
1.25mm² up to 12m long
1.5mm² up to 15m long
2.5mm² up to 25m long (2.5mm² flex won't easily fit in a 13A plug).
These come from the PAT testing recommendations, with the earth
fault loop impedance being the limiting factor.

Lengths can be increased with a proportional reduction in the value of
plug fuse value fitted in the extension lead, e.g. with a 5A fuse fitted,
31m, 39m, and 65m respectively for the three cable sizes above.

circular saw (1200 W) [at 240V that is 5A] asked the chap in the local
Hardware shop for cable large enough to deal with 2 kilowatt (mmm over
speccing as usual), he said he had nothing that could deal with that
much power 2k was "cooker sized", but my kettle (e.g.) is 2200 W, so
can't trust him as far as I can throw him.

--
Andrew Gabriel

soup wrote:
Does anyone have a favourite site, to work out the CSA required for a
piece of cable, basically I want to make up an extension to run a
circular saw (1200 W) [at 240V that is 5A] asked the chap in the local
Hardware shop for cable large enough to deal with 2 kilowatt (mmm over
speccing as usual),

starting with the wrong specs isnt going to help much


NT