I fitted a new dimmer switch a couple of weeks ago along with a new
light. The ceiling light has four 50 watt bulbs fitted and according
to the manufacturers instructions is suitable to be used with a dimmer
switch. The dimmer switch is rated at 300 watt.
My concern is that the switch gets very warm when the light is off. I
have just tried the switch at three different settings which made no
difference to the temperature of the switch.
Tested at dimmest, medium and full for around 15-20 minutes each.
I realise the switch may get warm in the on position but surely not in
the off position.
Any assistance on the matter would be appreciated.
With rated capacity of 300, the 200 watts of lamps doesn't sound like
a problem and the heat is noted in the 'off' position, however:
In the confined space of a typical switch wall box even the few watts
used by any solid state dimmer or timer circuit, even when it is in an
allegedly 'off' state, may feel warm.
Appears that solid state, so called 'Smart thermostats' timers and
dimmers use a little bit of power, flowing via the devices they
control 'all the time'. Probably only a watt or two each. So take 500
hours, at least, to use one unit (kilowatt hour) at whatever is the
cost of electricity.
If the heat is considered excessive (fire risk) get rid of the dimmer
entirely; or unscrew the bulbs when light not in use!
Not sure about quality standards in UK, but here in Canada there is
quite a lot of junk being sold, probably made very cheaply overseas,
that 'supposedly' (or falsely labelled?) meets Canadian CSA (Canadian
Standards Assoc.) or the USA UL (Underwriters Labs.) requirements.
But which in practice does not seem that reliable (some items don't
last long!), and/or causes RFI (Radio Frequency Interference) and
For example certain products are labelled "For incandescent and non
inductive loads only". Yet in the next aisle most of the bulbs being
sold are non incandescent CFLs (Compact Fluorescents)! And homeowners
often don't know what that means, except it is now supposed to be
'good' to use the newer style bulbs!
Other oddities; a ceiling fan controlled by a dimmer wall switch,
buzzing loudly ..... just not compatible. A Dimmer switch controlling
wall outlets for bedside or table lamps. Doesn't work well when a
radio-stereo system was plugged into same outlets! A homeowner who
used a light dimmer switch to slow down the AC induction motor of
their air exchanger fan. And then wondered why both it and the motor
burnt out! Didn't like the waveform I guess?
The more of these gadgets we use, often installed by those who have
little understanding of things electrical (No you don't have to be a
registered electrician, just know what you are doing!) the greater the
chance of incompatibilities/problems increase.
Most dimmers switch off properly, but some dont. If its not hot enough
to be a fire risk then no problem.
Your use of 200w on a 300w dimmer is asking for trouble though. It may
be in spec, but its a recipe for early failure.
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