Installed dimmer, less light intensity...

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Tim Mackey

• 3 Jan 2005

• #1

hi,
i replaced a one way switch with a two way dimmer. the one way switch had 3 lives going into the 'common' and 1 live going into '1-way'. it was hard to get the 3 common wires into the ~ socket in the dimmer because it is so small, but it works anyway.
the problem is the halogen spots don't seem as powerful before (with the dimmer turned up full). if its of any interest, the first 5 notches on the dimmer do nothing, the light remains in the off position. after that, there are 9 levels of intensity.
it hardly matters what notch the dimmer was on when i restored power does it?
i have 3 halogen spots, mains voltage, with 50w bulbs. the dimmer is a two way switch in a 1-way configuration.

thanks for any help
tim

 

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breezer

• 3 Jan 2005

• #2

since the lights were ok before you fitted the dimmer, it must be the dimmer. you should add the total wattage of the lamps and use a dimmer that is at least twice that

 

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Tim Mackey

• 3 Jan 2005

• #3

hi breezer. thanks for the explanation.
it's a 250 watt dimmer, and i have 150 combined wattage with the bulbs, so that missing 50 watts (from the 300w required) must be the reduced brightness. they still give off a lot of light, and are too bright to look at, so i might leave it as it is, unless its dangerous or wasting electricity?
thanks
tim

 

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breezer

• 3 Jan 2005

• #4

dimmer is likely to go bang

 

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Tim Mackey

• 3 Jan 2005

• #5

thanks breezer. i replaced it with a 400w dimmer instead and it has the full brightness now. of the 2 wiring DIY jobs i've done in my home, neither of them look like anything standard, when i compare with the diagrams online. with the switch, it had 3 lives going in to the "common" socket and one line (presumably the switched live, there was no tape on it) went in to "1-way". it was near impossible to squeeze those 3 lines into one socket in the dimmer. i don't know what the 2 extra lines (all the diagrams of 1-way lighting only have an input + output live wire) were doing there but i suspect the house was wired by an electrician who took shortcuts, not bothering to earth the upstairs lights or switches.
is it normal to have 3 live inputs to a switch?

thanks
tim

 

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notb665

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• 3 Jan 2005

• #6

If I remember right you have a new home, yes?

If so, the live wires are behind the switch now rather than at the fitting like they would've been before.

You say you have 3 lives into one terminal. Do you mean 3 reds/browns? If you power off, separate them, power on and measure the voltage on each how many are live?

 

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Tim Mackey

• 3 Jan 2005

• #7

yes, its 8 or 9 years old.
it is 3 brown live wires going directly into the switch, and one going out. no blues or earths to be seen at all.
unfortunately i don't have a meter thingy to test the voltage
on my first attempt to wire the switch, one of the lives came out of the socket when i pushed it into the wall and the whole upstairs lighting circuit didn't work once i put the fuse back on. i guess that is fairly obvious though if there is a break in the circuit!

 

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notb665

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• 4 Jan 2005

• #8

I reckon just one of the three browns will be live.

How about you buy a multimeter?

 

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plugwash

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• 4 Jan 2005

• #9

he said he had a single brown in one side and 3 in the other

sounds to me like the lone brown is the feed and the 3 together go off to the lights.

no earths to switch boxes is naughty though.....

your install is either double insulated singles or singles in conduit. with such systems it is normal to just take wires directly between where they are needed rather than doing any looping in at the fittings.

at least domestically in the uk such systems are fairly rare.