Hi, have put in first fix wiring for 8 GU10 50w recessed spots in the
ground floor ceiling, daisy-chained from the junction box with 1.5 mm
cable. Only when I glance at the instructions for the lights do I read
that the manufacturers advise no more that 5 be daisy-chained together.
My rusty school physics suggests that A = W/V, means load (amp) =
1.666A, which shouldn't be a problem. Would someone kindly point out
what I'm missing, as I'm feeling very thick!

Cheers,

Tom

"bookman" wrote in message
oups.com...
Hi, have put in first fix wiring for 8 GU10 50w recessed spots in the
ground floor ceiling, daisy-chained from the junction box with 1.5 mm
cable. Only when I glance at the instructions for the lights do I read
that the manufacturers advise no more that 5 be daisy-chained together.
My rusty school physics suggests that A = W/V, means load (amp) =
1.666A, which shouldn't be a problem. Would someone kindly point out
what I'm missing, as I'm feeling very thick!

Cheers,

Tom


Your calculations are correct.

8*50w = 400w
400w / 240v = 1.666A.

You can now expect:

1) Pedants to tell you thet the mains voltage is 230v ( which it isn't );
2) A host of Tokenist Greenies to berate you for not using CFLs.

Feel free to ignore both of them.

( But do consider whether the 8 spots will give the required coverage.
They tend to give a rather fierce 'projector' glare at one point, leaving
the rest of the room dark in comparison. They don't make for good general
lighting, unless you use lots of them. There are circumstances where this
works well, and those where it doesn't. This will incurr the greenies wrath,
as you will soon see, and worse, you will be changing the damn things every
other day. )

There may be wiring regulation issues that come into play, others will
advise.


--
Ron

You can now expect:

1) Pedants to tell you thet the mains voltage is 230v ( which it isn't );
2) A host of Tokenist Greenies to berate you for not using CFLs.

Feel free to ignore both of them.


My mains voltage as I type is 228.9.

Is that pedantic?

In article , Vortex
writes


You can now expect:

1) Pedants to tell you thet the mains voltage is 230v ( which it isn't );
2) A host of Tokenist Greenies to berate you for not using CFLs.

Feel free to ignore both of them.


My mains voltage as I type is 228.9.

Is that pedantic?



246.6 here!..
--
Tony Sayer

"tony sayer" wrote in message
...
In article , Vortex
writes


You can now expect:

1) Pedants to tell you thet the mains voltage is 230v ( which it
isn't );
2) A host of Tokenist Greenies to berate you for not using CFLs.

Feel free to ignore both of them.


My mains voltage as I type is 228.9.

Is that pedantic?



246.6 here!..
--
Tony Sayer


I wonder if you can purchase some kind of cheap device for logging mains
voltage against time.

18:00 to 20:00 in Winter our mains voltage is 215-220

Summer daytime it's 240V

There are an awful lot of I-squared-R's going to wastee in transmission
losses out there.

Something to investigate.

In article , vortex2
writes

"tony sayer" wrote in message
...
In article , Vortex
writes


You can now expect:

1) Pedants to tell you thet the mains voltage is 230v ( which it
isn't );
2) A host of Tokenist Greenies to berate you for not using CFLs.

Feel free to ignore both of them.


My mains voltage as I type is 228.9.

Is that pedantic?



246.6 here!..
--
Tony Sayer


I wonder if you can purchase some kind of cheap device for logging mains
voltage against time.

18:00 to 20:00 in Winter our mains voltage is 215-220

Summer daytime it's 240V

There are an awful lot of I-squared-R's going to wastee in transmission
losses out there.

Something to investigate.



That will be the supply impedance of the line and transformer supplying
you.

Most UPS units have some voltage logger and event recorder built in
which show quite wide variations sometimes more that the permitted ones
but getting the distribution companies to do something about that is
like banging your head 'agin a brick wall!..



--
Tony Sayer

On Wed, 13 Dec 2006 11:33:35 -0000, vortex2 wrote:

I wonder if you can purchase some kind of cheap device for logging mains
voltage against time.

FWIW the software that came with my UPS does this 24/7 on the server. I
really CBA to even look at it.

I wonder if you can purchase some kind of cheap device for logging mains
voltage against time.

18:00 to 20:00 in Winter our mains voltage is 215-220

Summer daytime it's 240V

There are an awful lot of I-squared-R's going to wastee in transmission
losses out there.

Something to investigate.

If you have an APC Smart UPS the software records voltage amongst other
things and presents it on a nice graph. It's probably possible to get the
recorded figures from a log file to export and keep as a voltage log.

Alan.

Vortex wrote:



You can now expect:

1) Pedants to tell you thet the mains voltage is 230v ( which it
isn't ); 2) A host of Tokenist Greenies to berate you for not using
CFLs.

Feel free to ignore both of them.


My mains voltage as I type is 228.9.

Is that pedantic?

We had a weird power thing the other day. Mains voltage dropped to 63
volts and stayed like that for several hours. I turned off as many
things as I could find - luckily nothing seemed to be damaged.
Interestingly, one of my computers kept going for quite some time
before it gave up!

--

/Simon

bookman wrote:

Hi, have put in first fix wiring for 8 GU10 50w recessed spots in the
ground floor ceiling, daisy-chained from the junction box with 1.5 mm
cable. Only when I glance at the instructions for the lights do I read
that the manufacturers advise no more that 5 be daisy-chained together.
My rusty school physics suggests that A = W/V, means load (amp) =
1.666A, which shouldn't be a problem. Would someone kindly point out
what I'm missing, as I'm feeling very thick!

It is more of an issue with GZ10s (i.e. 12V), where the current is
correspondingly 20 times higher, and a small drop in voltage tranlates
to a much bigger visible difference in light reduction.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Tom
I have linked 18 GU10's but used 20W bulbs in them instead of 50W's,
room size is 4m x 7m ceiling height is 4m (yes very high), I have
experimented and the best amount of light produced in my case is with
only 10 lights opperational giving a total of 200W.

Hope this is helpful.

Calum Sabey
(NewArk Traditional Kitchens 01556 690544)

Tom
I have linked 18 GU10's but used 20W bulbs in them instead of 50W's,
room size is 4m x 7m ceiling height is 4m (yes very high), I have
experimented and the best amount of light produced in my case is with
only 10 lights opperational giving a total of 200W.

Hope this is helpful.

Calum Sabey
(NewArk Traditional Kitchens 01556 690544)


Although pricey at the moment there are LED GU10 lamps which are getting
pretty good now in terms of light output. Look at Lyco's website.