On Oct 11, 10:40*am, Derek Geldard wrote:
On Sun, 11 Oct 2009 02:00:30 -0700 (PDT), NT
wrote:

Its not damage to the cable you are worried about, but drop in voltage..

Yup.

0.5mm2 bell wire has 88mV drop per amp per metre. A modern 60w fridge
thus sees 22mV per metre drop.

Lets say the lead is a huge 10m long, giving 0.44v total drop. So the
230v rated fridge, which must be capable of operating on the lower
limit of French 220v, ie only a bit over 200v, thus sees 240v - 0.44v
= 239.56v.

Sensible extension leads have even less effect.

Where do you get that amps figure from ?

from the 60w typical rating. Admittedly I ignored power factor, which
will add maybe 25% on, but makes no qualitative difference to the
outcome.


What is your figure for the inrush current?

You have measured it ?

From
http://wiki.answers.com/Q/Typical_current_draw_for_a_refrigerator

*Typical current draw for a refrigerator?

My 20 year old upright freezer is about 10A starting, 3.27 amp running
(263 watts)

My 10 year old fridge is very similar

(Figures from the US)

Derek

US fridges are different animals to UK ones. Typical run power on a
new machine here is around 60w. At 240v thats 0.25A, or a bit more
considering power factor.

If we use your ratio of 3:1 for startup current, then the Vdrop during
startup would be about 1.3v, leaving 238.7v for the compressor that's
rated to run on 220v nominal as well as 240v nominal.

Even if we used an aggressive figure of 16x start current, 16x 0.44v =
7v drop, leaving the machine 233v, when its rated to run ok at a bit
over 200v.

http://wiki.diyfaq.org.uk/index.php?...s#230v_or_240v

Numbers reveal the truth.


NT