Wiring two lamps together

flogen

Hey folks...

I'm trying to put together a relatively simple vanity mirror as a present - the plan is to use two of these things, and fix them to one of these (or something similar).

Ideally I'd like to be able to wire the two lamps onto one plug so as to make it a bit less cluttered - uber-ideally I'd also like to add a dimmer so the brightness of the bulbs can be adjusted accordingly.

The problem is I have zero experience with wiring or electricals.

Can anyone tell me if doing either or both of these things is possible/advisable and, if so, what I need to know to go about it?

If needs be I should be able to enlist the help of someone who (probably) knows what to do here, but if I can I'd like to be able to do it myself.

Thanks in advance.

aido79

flogen wrote: »

Hey folks...

I'm trying to put together a relatively simple vanity mirror as a present - the plan is to use two of these things, and fix them to one of these (or something similar).

Ideally I'd like to be able to wire the two lamps onto one plug so as to make it a bit less cluttered - uber-ideally I'd also like to add a dimmer so the brightness of the bulbs can be adjusted accordingly.

The problem is I have zero experience with wiring or electricals.

Can anyone tell me if doing either or both of these things is possible/advisable and, if so, what I need to know to go about it?

If needs be I should be able to enlist the help of someone who (probably) knows what to do here, but if I can I'd like to be able to do it myself.

Thanks in advance.

Electrically it is possible but not sure how it would work in reality. You will need a junction box with 4 connectors to join the flexes from the lights together. From this you will connect a plug with a flex and join the neutral to the neutral of the lights and the earth to the earth of the lights. Put the live of the lights in the one connector and the live from the plug into the other. Next take a twin brown to a dimmer switch and connect one brown to the lights and the other to the plug in the connectors. Connect the other end of that cable to the switch, one brown to common and one to L1.
Your biggest problem unless you are good at things like this will be fixing it all to the mirror so it doesn't look like something that was made in the dark.

flogen

aido79 wrote: »

Electrically it is possible but not sure how it would work in reality. You will need a junction box with 4 connectors to join the flexes from the lights together. From this you will connect a plug with a flex and join the neutral to the neutral of the lights and the earth to the earth of the lights. Put the live of the lights in the one connector and the live from the plug into the other. Next take a twin brown to a dimmer switch and connect one brown to the lights and the other to the plug in the connectors. Connect the other end of that cable to the switch, one brown to common and one to L1.
Your biggest problem unless you are good at things like this will be fixing it all to the mirror so it doesn't look like something that was made in the dark.

Thanks for that.

Excuse the child-like doodling, but is the attached image what you mean by the above?

I can see what you mean about trying to make it neat - even fixing it to the back of the mirror may be an issue as it would make it difficult to mount on a wall.

Would it simplify the process at all if I could find an inline dimmer that could be added to the flex leading to the plug? I've seen a few in the US but not found an Irish/British example... not sure if they exist tbh.

aido79

flogen wrote: »

Thanks for that.

Excuse the child-like doodling, but is the attached image what you mean by the above?

I can see what you mean about trying to make it neat - even fixing it to the back of the mirror may be an issue as it would make it difficult to mount on a wall.

Would it simplify the process at all if I could find an inline dimmer that could be added to the flex leading to the plug? I've seen a few in the US but not found an Irish/British example... not sure if they exist tbh.

Yeah that's exactly it on the wiring. An inline dimmer will do the trick. I'm sure you could find one on ebay or something.

flogen

aido79 wrote: »

Yeah that's exactly it on the wiring. An inline dimmer will do the trick. I'm sure you could find one on ebay or something.

Great, thanks. Will have a look on ebay and see if there's anything going.

Just a final question on the voltage side - anything I need to bear in mind if I do put the two sets of lamps together in regards to the fuse in the plug?

And I know a lot of dimmers can have limits in terms of wattage/voltage etc - what should I be looking out for to ensure everything plays nice when done?

aido79

flogen wrote: »

Great, thanks. Will have a look on ebay and see if there's anything going.

Just a final question on the voltage side - anything I need to bear in mind if I do put the two sets of lamps together in regards to the fuse in the plug?

And I know a lot of dimmers can have limits in terms of wattage/voltage etc - what should I be looking out for to ensure everything plays nice when done?

Just add the wattage of all the bulbs together and as long as the total isn't bigger than the rating of the switch. It almost definitely won't be as most switches are rated at 10 amps which is around 2500 watts. With bulbs of that wattage you wouldn't be able to use the mirror :-P

brightspark

aido79 wrote: »

Just add the wattage of all the bulbs together and as long as the total isn't bigger than the rating of the switch. It almost definitely won't be as most switches are rated at 10 amps which is around 2500 watts. With bulbs of that wattage you wouldn't be able to use the mirror :-P

Most dimmers are rated at between 250 and 400watts!
That's not to say you can't get higher rated ones.

OP please get someone competent to help you or at least check it out afterwards, I'd worry about especially about poor connections and earthing issues, that may not stop the lights from working but could be potential dangerous.

flogen

brightspark wrote: »

Most dimmers are rated at between 250 and 400watts!
That's not to say you can't get higher rated ones.

So does that mean that, once the wattage of all the bulbs combined stays below the rated figure (whatever it may be), I'm good to go?

If it works I might just make life simpler for myself and go with this yoke instead for the dimmer:

http://www.ikea.com/ie/en/catalog/products/20069079/

OP please get someone competent to help you or at least check it out afterwards, I'd worry about especially about poor connections and earthing issues, that may not stop the lights from working but could be potential dangerous.

Thanks - I do plan to; not something I'm willing to be too lax about!

flogen

Sorry - another question...

If I do go for an inline dimmer (or none at all) will I be able to use a 3 connection junction box instead of 4? So I could connect the lamps' lives to the flex's live rather than doing them separately with the dimmer attached to both as suggested above??

aido79

flogen wrote: »

Sorry - another question...

If I do go for an inline dimmer (or none at all) will I be able to use a 3 connection junction box instead of 4? So I could connect the lamps' lives to the flex's live rather than doing them separately with the dimmer attached to both as suggested above??

Yes that will work.

If you're using dimmable leds you'll need a trailing edge dimmer.
You also need to de-rate the dimmer to 10% plated for use with most leds.

flogen

Sir Liamalot wrote: »

If you're using dimmable leds you'll need a trailing edge dimmer.
You also need to de-rate the dimmer to 10% plated for use with most leds.

The dimmable element is looking more complicated by the second! I might just try the plug-in dimmer switch from Ikea... if that doesn't work it'll just have to do without that particular feature!

flogen

Hi again.

Picked up the lamps and when I checked the wiring there was only a live and neutral - will that be a problem for me if I want to wire them together to a plug? (They're designed as wall lamps)

Cheers.

The earth is just a safety "overflow" it's not connected to the bulbs just the metal bits in case of wayward electrons escaping.

flogen

Sir Liamalot wrote: »

The earth is just a safety "overflow" it's not connected to the bulbs just the metal bits in case of wayward electrons escaping.

Grand - it seems the US ones have an earth attached to a (metal, I think) plate on the back of each lamp but that plate wasn't with the ones I bought.

I wired everything up this afternoon and it worked fine - so thanks everyone for the advice. Just need to fix it to the mirror now and we should be good to go.

One last thing I'm not sure on is the fuse - I have ten 3.5W bulbs on the lamps, so what kind of amps should the fuse on the plug be?

If there's no exposed metal it's double insulated you don't need an earth.

The fuse is to protect the cable not the fixture. If it's 1.5mm² cable then 13A is fine. 0.75mm² 5A or 7A.

35W / 220V = 150mA

flogen

Sir Liamalot wrote: »

If there's no exposed metal it's double insulated you don't need an earth.

Yeah - it's all plastic on the outside (some of which is 'chrome' but plastic nonetheless)

The fuse is to protect the cable not the fixture. If it's 1.5mm² cable then 13A is fine. 0.75mm² 5A or 7A.

35W / 220V = 150mA

Great, thanks.

That's the symbol for double insulated if that's on it somewhere no earth required.