A
Andrew Chesters
Guest
Spehro Pefhany wrote:
SNIP
SNIP
Yep!
A
Andrew Chesters
Guest
John Rumm wrote:
SNIP
SNIP
D
Darcy B
Guest
On 12 Feb 2005, Ian Stirling wrote:
What is earth fault loop impedance?
(Yup, I have tried Google!)
What is earth fault loop impedance?
(Yup, I have tried Google!)
S
Sammo
Guest
On 12 Feb 2005, Interfacebus.com wrote:
Nice table.
What a pity they didn't list the cross-sectional area (calculated
from the diameter) as it seems that many people refer to cross
sectional area when determining current capacity.
Nice table.
What a pity they didn't list the cross-sectional area (calculated
from the diameter) as it seems that many people refer to cross
sectional area when determining current capacity.
S
Sammo
Guest
On 12 Feb 2005, Andrew Chesters wrote:
CU?
CU?
I
Ian Stirling
Guest
In uk.d-i-y Sammo <noone@no-where.com> wrote:
The box where the electricity comes into the house, which contains
RCD/breakers/fuses for the individual circuits.
Consumer Unit.
The box where the electricity comes into the house, which contains
RCD/breakers/fuses for the individual circuits.
O
Owain
Guest
"John Rumm" wrote
| Depends on if you are in serise or parallel with it!
I *still* get confused with blue being live because it's a 'brighter' colour
than brown in cables; WTF did cerise come into it? Will Channel 5 be giving
us Colin & Justin's How Not To Write Wiring Regulations in the near
future...
Owain
(This posting may contain UK-specific cultural references.)
| Depends on if you are in serise or parallel with it!
I *still* get confused with blue being live because it's a 'brighter' colour
than brown in cables; WTF did cerise come into it? Will Channel 5 be giving
us Colin & Justin's How Not To Write Wiring Regulations in the near
future...
Owain
(This posting may contain UK-specific cultural references.)
B
Bill Woods
Guest
On 17 Feb 2005, =?UTF-8?B?UGFsaW5kcuKYu21l?= wrote:
This sounded interesting so I checked out B&Q's website by searching
for "generator".
I found this http://tinyurl.com/4bo8k They cost from Ł250 to Ł430!
What was the Ł100 one you are refiing to?
This sounded interesting so I checked out B&Q's website by searching
for "generator".
I found this http://tinyurl.com/4bo8k They cost from Ł250 to Ł430!
What was the Ł100 one you are refiing to?
R
Rob Morley
Guest
In article <9607A70CB733351D7E@130.133.1.4>, "Bill Woods"
woods_b@emercom.com says...
http://www.screwfix.com/app/sfd/cat/pro.jsp?id=43168&ts=69051
woods_b@emercom.com says...
http://www.screwfix.com/app/sfd/cat/pro.jsp?id=43168&ts=69051
B
Bill Woods
Guest
On 24 Feb 2005, Rob Morley wrote:
Interesting. Do you know where I can find the manufacturer's website
as I would be interested in reading so specs on this and related
generators.
Interesting. Do you know where I can find the manufacturer's website
as I would be interested in reading so specs on this and related
generators.
P
Palindrâťme
Guest
Sammo wrote:
have considered just the longer lengths.
Basically, you have two factors to consider:
The first is how hot the wire will get. Now, provided that
the cable is unwound and in the open air, then its length is
immaterial. If you coil the cable up or cover it in
something that restricts the flow of heat from it, that is a
different matter. However, for an unwound cable, the rated
current, say 10 amperes, is the maximum that is allowed due
to heat constraints. Pass more current than this and the
wire will get too hot. Pass a lot more current than this and
the insulation could fail.
The second is the volt drop. Its resistance is about 0.02
ohms per metre - so a 60 m length will have a resistance of
1.2 ohms and will drop 1.2 volts per ampere. A 120 m length
would drop 2.4 volts per ampere.
Now the equipment at the far end of the cable will have a
specified range of input voltage for which it was designed.
You must simply ensure that it gets the minimum rated
voltage, or higher, at the current it draws. This minimum
voltage will depend on the equipment type.
As a rough guide, losing 12 volts in 240 is probably going
to be fine. So, you could use a 60 metre cable at 10 amperes
or 120 metre cable at 5 amperes.
If your load is happier with a lower minimum voltage, say
220 volts, then you could run the 120m cable at about 8
amperes. However, you would still be limited to 10 amperes
for the 60 metre cable, because 10 amperes is the most the
cable should be used to carry, irrespective of length.
Purely resistive loads, like heaters, aren't terribly fussed
if their voltage is a bit low - so you could happily run a
2kW heater at the end of 120 metres of your cable. If you
have a lamp plugged in at the far end, then it will get
noticeably dimmer when the heater is switched on. This isn't
a safety problem, although it might appear so.
Some loads are very fussy about their minimum voltage but
even those should be happy with 10 amperes taken from your
60 metre cable.
Hope that helps.
Sue
30 metres at 10 amperes isn't going to be a problem - so I
have considered just the longer lengths.
Basically, you have two factors to consider:
The first is how hot the wire will get. Now, provided that
the cable is unwound and in the open air, then its length is
immaterial. If you coil the cable up or cover it in
something that restricts the flow of heat from it, that is a
different matter. However, for an unwound cable, the rated
current, say 10 amperes, is the maximum that is allowed due
to heat constraints. Pass more current than this and the
wire will get too hot. Pass a lot more current than this and
the insulation could fail.
The second is the volt drop. Its resistance is about 0.02
ohms per metre - so a 60 m length will have a resistance of
1.2 ohms and will drop 1.2 volts per ampere. A 120 m length
would drop 2.4 volts per ampere.
Now the equipment at the far end of the cable will have a
specified range of input voltage for which it was designed.
You must simply ensure that it gets the minimum rated
voltage, or higher, at the current it draws. This minimum
voltage will depend on the equipment type.
As a rough guide, losing 12 volts in 240 is probably going
to be fine. So, you could use a 60 metre cable at 10 amperes
or 120 metre cable at 5 amperes.
If your load is happier with a lower minimum voltage, say
220 volts, then you could run the 120m cable at about 8
amperes. However, you would still be limited to 10 amperes
for the 60 metre cable, because 10 amperes is the most the
cable should be used to carry, irrespective of length.
Purely resistive loads, like heaters, aren't terribly fussed
if their voltage is a bit low - so you could happily run a
2kW heater at the end of 120 metres of your cable. If you
have a lamp plugged in at the far end, then it will get
noticeably dimmer when the heater is switched on. This isn't
a safety problem, although it might appear so.
Some loads are very fussy about their minimum voltage but
even those should be happy with 10 amperes taken from your
60 metre cable.
Hope that helps.
Sue
O
Owain
Guest
"Peter A Forbes" wrote
| >Those poor souls that put a hundred feet or so of 18GA (about 1mm sq)
| >extension cord on their weed wackers
It's a different language isn't it
| >soon find that not only does it run slow, but the motor overheats.
| >So we have extension cords that are 16 or 14 gauge, and can
| > handle the extra current. But people are too cheap to pay double
| > for the heavy duty extension cord, so they end up eating
| >their money up in burned out motors.
| Why use anything as small as 1mm sq cable???
If it's in Wall-mart, they'll buy it.
Owain
| >Those poor souls that put a hundred feet or so of 18GA (about 1mm sq)
| >extension cord on their weed wackers
It's a different language isn't it
| >soon find that not only does it run slow, but the motor overheats.
| >So we have extension cords that are 16 or 14 gauge, and can
| > handle the extra current. But people are too cheap to pay double
| > for the heavy duty extension cord, so they end up eating
| >their money up in burned out motors.
| Why use anything as small as 1mm sq cable???
If it's in Wall-mart, they'll buy it.
Owain
W
Watson A.Name - \"Watt Su
Guest
"Peter A Forbes" <diesel@easynet.co.uk> wrote in message
news:rpks01dusj3e57g4n976ii30l4ncc1stpj@4ax.com...
size it is! Ask one of the ladies at work, she has first-hand
experience!
As for heavier cable, I know that, but the average consumer doesn't.
She uses an 18 gauge extension cord with the cast plastic socket from
the wall to her ironing board, and wonders why she smells melted plastic
when she irons! "Gee, I swear that when I plugged it in, the socket
wasn't all brown and charred." Doh!
The guy has what's at hand and just plugs three 25 footers together to
wack his weeds. The plugs and sockets also drop some voltage because of
their resistance, so he ends up with a burned out motor after it ran a
couple hours at 85 to 90VAC. Doh.
news:rpks01dusj3e57g4n976ii30l4ncc1stpj@4ax.com...
Hey, a hedge trimmer will cut the cable cleanly in half, no matter what
size it is! Ask one of the ladies at work, she has first-hand
experience!
As for heavier cable, I know that, but the average consumer doesn't.
She uses an 18 gauge extension cord with the cast plastic socket from
the wall to her ironing board, and wonders why she smells melted plastic
when she irons! "Gee, I swear that when I plugged it in, the socket
wasn't all brown and charred." Doh!
The guy has what's at hand and just plugs three 25 footers together to
wack his weeds. The plugs and sockets also drop some voltage because of
their resistance, so he ends up with a burned out motor after it ran a
couple hours at 85 to 90VAC. Doh.
W
Watson A.Name - \"Watt Su
Guest
<ehsjr@bellatlantic.net> wrote in message
news:REtPd.19619$ya6.6306@trndny01...
over $15,000 to get it repaired. Obviously that was before 1996, when
the present batteries were installed. So the price would be somewhat
higher today.
The spare conduit is already in place underground, all that is needed
are the power cable and associated switchgear.
We regularly have the 4160VAC cabling HiPot tested on campus, and on
occasion a section has to be replaced. Y'ever see this stuff? It's
600MCM, with heavy insulation and shielding. The copper is as big as
your thumb, and it's expensive!! I have a footlong section of it on my
desk, and when someone asks what it is, I tell them it's high speed
datacomm cable! ;-) WOW! Really??
I googled for that and this URL says that 600MCM is 29mm. Fat pipe!
Imagine all the data you could shove thru it!
http://www.appatech.com/a-30.htm
news:REtPd.19619$ya6.6306@trndny01...
Last time we had a major failure of the batteries and rectifier it costWatson A.Name - "Watt Sun, the Dark Remover" wrote:
"Sammo" <noone@no-where.com> wrote in message
news:95FB7BA1F25441A7D4@130.133.1.4...
I am in the UK (so mains voltage is about 230V or 240V).
I'm in the U.S. and this gives me a flashback on what I was thinking
about trying a few months ago. We have a PBX at work that's on 48V
batteries, but the batteries are 9 yrs old and need replacing. They
cost a bundle so I thought it would be possible to run a power cable
underground to the big UPS we have in our computer room. Problem is
that the PBX's rectifier takes 30A max at 120VAC, or about 3.6kW.
And
the distance between is about 1300 feet or about 400m.
I would guess that the UPS output should go into a transformer and
come
out 480VAC, so the cable losses would be minimized. Then another
transf
on the PBX end to bring it back to 120VAC.
Hmmm... if you do it, just connect the PBX directly to the
480 volts. Just think how much faster the phone calls will
be at 480 vs 48!
I think installing a half mile of # 4 might be "politically" cost
prohibitive, regardless of the technical merits. And I doubt
it would be a good financial solution. How many times
can you replace the batteries for the cost of digging a
1/4 mile trench, and installing conduit, cable, fittings,
transformers, etc ?
over $15,000 to get it repaired. Obviously that was before 1996, when
the present batteries were installed. So the price would be somewhat
higher today.
The spare conduit is already in place underground, all that is needed
are the power cable and associated switchgear.
We regularly have the 4160VAC cabling HiPot tested on campus, and on
occasion a section has to be replaced. Y'ever see this stuff? It's
600MCM, with heavy insulation and shielding. The copper is as big as
your thumb, and it's expensive!! I have a footlong section of it on my
desk, and when someone asks what it is, I tell them it's high speed
datacomm cable! ;-) WOW! Really??
I googled for that and this URL says that 600MCM is 29mm. Fat pipe!
Imagine all the data you could shove thru it!
http://www.appatech.com/a-30.htm
[snip]
W
Watson A.Name - \"Watt Su
Guest
"John Rumm" <see.my.signature@nowhere.null> wrote in message
news:420e7d2d$0$29771$ed2619ec@ptn-nntp-reader02.plus.net...
up by a 300kW Caterpillar diesel generator, with 300 gallons of fuel in
the tank. It's supposed to run for at least 8 hours, so it does have an
advantage. We've had power outages that last for hours, so having that
much battery backup on the PBX would cost a lot more. But we'll
probably buy a couple APS 2.2kW UPses and put the PBX system on those.
They should last for close to an hour.
news:420e7d2d$0$29771$ed2619ec@ptn-nntp-reader02.plus.net...
That's probably what will happen. But the computer room's UPS is backed
up by a 300kW Caterpillar diesel generator, with 300 gallons of fuel in
the tank. It's supposed to run for at least 8 hours, so it does have an
advantage. We've had power outages that last for hours, so having that
much battery backup on the PBX would cost a lot more. But we'll
probably buy a couple APS 2.2kW UPses and put the PBX system on those.
They should last for close to an hour.
W
Watson A.Name - \"Watt Su
Guest
"Mike" <nospam@bt.com> wrote in message
news:cum1in$ci0$1@news6.svr.pol.co.uk...
This URL shows a pic of the business end of a weed wacker.
Traditionally they use monofilament. There are both electric and gas
engine types, but the noisy gasoline engines (and leaf blowers) are
sometimes banned from some communities.
http://www.nycgovparks.org/sub_newsroom/innovations/ino_06_2000.pdf
news:cum1in$ci0$1@news6.svr.pol.co.uk...
Where are you from? Ever heard of Google?
This URL shows a pic of the business end of a weed wacker.
Traditionally they use monofilament. There are both electric and gas
engine types, but the noisy gasoline engines (and leaf blowers) are
sometimes banned from some communities.
http://www.nycgovparks.org/sub_newsroom/innovations/ino_06_2000.pdf
P
Peter Bennett
Guest
On Sat, 12 Feb 2005 17:17:16 -0800, "Watson A.Name - \"Watt Sun, the
Dark Remover\"" <NOSPAM@dslextreme.com> wrote:
I expect that your "4 volt cells" are actually two cell lead-acid
batteries, with each cell good for 2.1 volts.
--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca
Dark Remover\"" <NOSPAM@dslextreme.com> wrote:
I don't know of any 4 volt rechargeable cell chemistry.
I expect that your "4 volt cells" are actually two cell lead-acid
batteries, with each cell good for 2.1 volts.
--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca
P
Peter Bennett
Guest
On Sat, 12 Feb 2005 11:08:03 -0800, "Watson A.Name - \"Watt Sun, the
Dark Remover\"" <NOSPAM@dslextreme.com> wrote:
make one of them tapped, so you can select an appropriate tap to
compensate for the voltage loss in the cable.
--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca
Dark Remover\"" <NOSPAM@dslextreme.com> wrote:
If you're going to use transformers at each end of the link, you can
make one of them tapped, so you can select an appropriate tap to
compensate for the voltage loss in the cable.
--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca
P
Paul Miller
Guest
"Sammo" <noone@no-where.com> wrote in message
news:95FB7BA1F25441A7D4@130.133.1.4...
much difference(resistive load) if the cable is protected by the correct
fuse in the plug.
The big problem is going to be earth loop impedance, I know it sounds
trivial
because it will work fine, but you did quote a PSC figure of 120A......must
be
a TT instalation. Please make sure you have a RCD on this circuit..
Regards,
Paul Miller iEng MIIE (elec)
news:95FB7BA1F25441A7D4@130.133.1.4...
I would say 2.5kw at 30M and around 2Kw at 60M. Its not gonna make
much difference(resistive load) if the cable is protected by the correct
fuse in the plug.
The big problem is going to be earth loop impedance, I know it sounds
trivial
because it will work fine, but you did quote a PSC figure of 120A......must
be
a TT instalation. Please make sure you have a RCD on this circuit..
Regards,
Paul Miller iEng MIIE (elec)
W
Watson A.Name - \"Watt Su
Guest
"Peter Bennett" <peterbb@somewhere.invalid> wrote in message
news:42jt01h7q5dpasoeufg6gfa0d7mu1qmkcl@news.supernews.com...
news:42jt01h7q5dpasoeufg6gfa0d7mu1qmkcl@news.supernews.com...
I expect you're right. Two cells in a case.