All the TLC two gang dimmers seem to be 400 watt each - but not for LV use.
The LV ones are 300 2 gang, 400 single.
I've got an old MK Superswitch somewhere that was 1000w in a one gang
size, but again for GLS only. I'm surprised there's not a difference
between plastic and metal plate ones these days - there used to be.
*I have my own little world - but it's OK...they know me here*
Dave Plowman firstname.lastname@example.org London SW 12
Andy, thanks this is very useful stuff. I also notice on tlc's
website that MK do "Grid Dimmers for Low Voltage Lighting", with
sliding control. Why are the ones you have pointed to not stated as
being "dimmers for LV lighting"? You say they are suitable for LV
lighting, which is good, but I'm curious as to why there is a specific
grid range for LV lighting in the sliding type. Presumably the ones
you have pointed to are suitable for LV lighting at their specified
loading (i.e. the 400W dimmer will power 400W of LV lighting, not
down-rated to something smaller as I have learned happens with certain
dimmers powering LV lighting)?
[rest of helpful post cut for brevity]
On 2 Feb 2004 05:48:46 -0800, email@example.com (Michael Brewer)
These are a generic part and not made by MK.
They make only the round knob type. These are suitable for mains and
LV as long as a suitable transformer is used.
I've just been looking at this again, and dug out the notes that I
wrote when I installed my own, following studying the GridPlus
datasheet and a call to MK's technical department.
The modules are rated OK, the issue is getting the heat away.
There is a row limit and a plate limit for the Grid system, and for a
single row of 3 in a single box there is a total plate limit of 380W
for halogen lamps of mains or LV, so the idea of two modules in a
triple box won't work.
I reviewed how I did my layout and why. The top row has one 400W
dimmer for some mains halogens and some standard switches.
The bottom row has 250W dimmers, but they are each connected to no
more than four 20W LV lamps per dimmer.
Overall, the lights being dimmed work out to just under the 600W plate
So.... realistically, it looks like you will be back to two separate
plates as the most practical solution.
Isn't this slightly bonkers? They do a 400W double module that is above the
plate limit of 380W all on its own. So just how would you accommodate a
400W module? Does that 380W plate limit only apply to powering halogens?
According to the datasheet, the row limit is only 380W until you get to a
whopping 18 or 24 module plate. So presumably your 400W dimmer is not fully
loaded either? Either that or your kitchen is a fantastic light
Who would have thought it would be so complicated? Until I got into this, a
switch was a switch was a switch. Interesting though.
Another thing I learned by looking at the "standard" MK dimmer switch
datasheet is that even though you might think that your dimmer switch will
power your 400W total of halogens, it then says that it will only control a
maximum of 4 transformers. Aaargh ! I was planning for each hologen to
have its own transformer ! Is this transformer limit common to all dimmer
switches? Please say no !
On Mon, 2 Feb 2004 21:24:18 -0000, "Michael Brewer"
Well it is, but the 400W dimmer has 300W on it.
Normally grid switches are used in offices or other commercial
applications. There are all kinds of modules available, and others
which could be put together that are not compatible from a technical
or a regulatory perspective.
The technology is remarkably similar at the power end of these. The
control arrangements vary - for example soft start like the K4500
If you are going to give each halogen its own transformer, wouldn't it
be easier to use mains ones?
400w each gang I think. Leastways I have 6x 50W LV's happily working off
one bank, and 3 off another, and 3x40w candles on the third. All on one
large plate - as in double mains socket size.
I have had a LOT of problems with that range at first tho - all the
candle bulb equipped circuits have blown the triacs, but I got free
upgraded modules and they are all fine now.
The LV stuff - running of electronic transformers - has been flawless.
Apparently candle bulbs do >10A when they blow and arc over for
considerable periods. They ALWAYS trip my 6A circuits when they go.
I should add that the heritage replacement triac modules - now standard
I believe- have been faultless.
I am not sure these are the ones I have, but here is a 400W double
I think the ones I have are from M Marcus - thats the manufacture - but
they are not webbed up. I got them fromn cambridge electrical discount.
It seems that 400W on a single, and 300W on a double, is the order of
the day. Or 400W on a triple on a big metal face plate.
My electronic transformers were part of a rather shoddy kit from the
same shop (track units) and a big newey and eyere own brand electronic
to drive the second bank of three LV's. The dimmers are nothing special,
but the transformer units awere slod as 'fully dimmable' amnd in fact
I suspect there are different things gong on with dimamble LV lighting
- that is
(i) some electronics can't be dimmed.
(ii) some electronics are designed to respond to the dimmer output
correctly. These require no derating or specialised dimmers
(iii) Toroids put a weird load on the dimmers, and probably need a
specially designed and derated dimmer. Dimmers 'designed for LV'
probably WILL work with toroids.
IME LV's put far less load on teh dimmers than incandescents. Mosrt have
slow atrt up featires, and so don't surge. You can PROBABLY drive up to
8 50W LV's off a 250W dimmer in reality, tho it may get warm.
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