How do I wire multiple lights together?

[gentlegreen]

Sorry - all I meant was that lamp holders are generally rewireable .... and if you simply cut the wires you could choose to wire them any way you wanted ..

 

[chymaera]

How do I go about wiring up multiple lightbulbs from a single plug point?

Say I wanted to wire up 5 lights round a mirror - like a hollywood dressing room. What electrickery do I need to master?

Commercial "buzz bar" like the ones used in shops for multiple lighting.
Or use a 12 volt system, (very easy to buy now as the muppets on TV Destroy It Yourself programs are always using them.)

 

[Citizen66]

Sorry - all I meant was that lamp holders are generally rewireable .... and if you simply cut the wires you could choose to wire them any way you wanted ..

You wouldn't need to cut the wires if they were just bog standard lamp holders. Just change the neutral to loop feed between each light and make the last light's neutral the one that is the return. Nobody does this though, there's no point, it's inefficient.

 

[gentlegreen]

Inefficient in the sense that wiring incandescents in series puts all the lamps down into the region where the biggest proportion of what they emit is heat .. fluorescents are unlikely to strike at all.

/pedant

 

[Citizen66]

Inefficient in the sense that wiring incandescents in series puts all the lamps down into the region where the biggest proportion of what they emit is heat .. fluorescents are unlikely to strike at all.

/pedant

They would produce the same amount of light that the current reaching them would allow but would reduce in brightness sequentially if not enough power is available where as lights wired in parallel the load is spread more evenly.

As you rightly state, fluorescents can't be wired in series as they wouldn't ignite. That's why they are pre-wired in parallel

 

[gentlegreen]

Sorry, but that defies the basic laws of physics
All lamps would have the same (much reduced) brightness.

This reminds me of a passage in "Zen and the Art of Motorcycle Maintenance" :-

A light switch in DeWeese's studio didn't work and he asked Phædrus if he knew what was wrong with it. He had a slightly embarrassed, slightly puzzled smile on his face, like the smile of an art patron talking to a painter. The patron is embarrassed to reveal how little he knows but is smiling with the expectation of learning more. Unlike the Sutherlands, who hate technology, DeWeese was so far removed from it he didn't feel it any particular menace. DeWeese was actually a technology buff, a patron of the technologies. He didn't understand them, but he knew what he liked, and he always enjoyed learning more.

He had the illusion the trouble was in the wire near the bulb because immediately upon toggling the switch the light went out. If the trouble had been in the switch, he felt, there would have been a lapse of time before the trouble showed up in the bulb. Phædrus did not argue with this, but went across the street to the hardware store, bought a switch and in a few minutes had it installed. It worked immediately, of course, leaving DeWeese puzzled and frustrated. "How did you know the trouble was in the switch?" he asked.

http://64.233.183.104/search?q=cach...e+maintenance+light+switch&hl=en&ct=clnk&cd=1

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When I said fluorescents, I meant individually ballasted ones, double linears are wired in series with one ballast and two seperate starters.

Two loads in series actually consume half the power of one. (a bit more than that because they run cooler and so have lower resistance)

60 watt lamp :-

I=W/V = 60/240 = 0.25A
R = V/I = 240/0.25 = 960 ohms

2 x 60 watt lamps in series :-

I = V/R = 240 / 1920 = 0.125 A
W=IV = 0.125 x 240 = 30 watts

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[Citizen66]

Sorry, but that defies the basic laws of physics
All lamps would have the same (much reduced) brightness.

When I said fluorescents, I meant individually ballasted ones, double linears are wired in series with one ballast and two seperate starters.


Two lamps in series consume half the power of one. (a bit more than that because they run cooler and so have lower resistance)

60 watt lamp :-

I=W/V = 60/240 = 0.25A
R = V/I = 240/0.25 = 960 ohms

2 x 60 watt lamps in series :-

I = V/R = 240 / 1920 = 0.125 A
W=IV = 0.125 x 240 = 30 watts

Gentlegreen, if the current (ampage) is available then they will light to their stated brightness (wattage) nomatter how they're wired but lights in series are less efficient than in parallel.

Please don't be silly and start pushing this issue as I do this for a living and have certificates coming out of my ears on the subject.

When I said fluorescents, I meant individually ballasted ones, double linears are wired in series with one ballast and two seperate starters.

And what if you needed to fill a room with a hundred fluorescent lamps? What then?

 

[gentlegreen]

They would produce the same amount of light that the current reaching them would allow but would reduce in brightness sequentially if not enough power is available where as lights wired in parallel the load is spread more evenly.

OK I'll let you off - just a rather odd way of putting it ... the "sequential" bit made me think we were entering the time domain ...

 

[Citizen66]

OK I'll let you off - just a rather odd way of putting it ...

Your equation is agreeing with what I'm saying that lights in series are more inefficient so I don't know why you're wanting to argue the same point I've made to be honest.

 

[chymaera]

And what if you needed to fill a room with a hundred fluorescent lamps? What then?

I would suggest discussing that on a publicly accessable internet forum is not a good idea.

 

[WouldBe]

Gentlegreen, if the current (ampage) is available then they will light to their stated brightness (wattage) nomatter how they're wired but lights in series are less efficient than in parallel.

No they won't as the current is determined by the resistance which increases when the bulbs are connected in series.

If you don't believe me try it.

 

[Citizen66]

No they won't as the current is determined by the resistance which increases when the bulbs are connected in series.

If you don't believe me try it.

That is what I'm saying. less efficient = less lumins emmitted - christ this is like hitting my head against a brick wall. A lamp is a resistor you are right. What are we arguing about?

If the wattage used is lower than the available current using whatever funky equation you want then they will still be as bright. There is a thresh hold.

The other reason not to wire in series (people will know this from christmas lights) is that if one of the lamps blow they will all not illuminate.

 

[gentlegreen]

If the wattage used is lower than the available current using whatever funky equation you want then they will still be as bright. There is a thresh hold.

As I said before it seems to be a matter of language.

What do you mean by "threshold" ?

The available current is to all intents infinite - about 100 amps per household or 5 amps on a lighting circuit ..

Two (240 volt) 60 watt incandescents in series will emit approx 15 watts each of mostly heat - maybe a dull glow. (actually a bit more because of the resistivity of tungsten).

If you wanted to wire your house in series you would need to buy 110 volt or lower voltage lamps - depending on how long the strings.

I have no particular expertise here - piss poor physics O Level in 1976 and a TEC in Electronics in 1981 .. but I do have experience of wiring lamps in series. I have 83 LEDs on my pushbike.

 

[WouldBe]

That is what I'm saying. less efficient = less lumins emmitted - christ this is like hitting my head against a brick wall. A lamp is a resistor you are right. What are we arguing about?

If the wattage used is lower than the available current using whatever funky equation you want then they will still be as bright. There is a thresh hold.

That's the bit that's causing the confusion. They can 'still be as bright'. By halving the current through 2 60W bulbs in series you're halving the overall wattage and as the bulbs are in series then there is only half the voltage across each bulb. So as gentle green has already correctly stated teh max wattage of each bulb is now only 15W.

That would need some secret over unity way to make a 60W bulb glow at the same brightness with only 15W of power available to it.

 

[Citizen66]

That's the bit that's causing the confusion. They can 'still be as bright'. By halving the current through 2 60W bulbs in series you're halving the overall wattage and as the bulbs are in series then there is only half the voltage across each bulb. So as gentle green has already correctly stated teh max wattage of each bulb is now only 15W.

That would need some secret over unity way to make a 60W bulb glow at the same brightness with only 15W of power available to it.

Sorry. I wasn't talking about the example equation that gentlegreen has given and maybe that's where the confusion is.

If he has given an example where a certain amount of power is available to meet the conditions for this particular argument then granted he's probably right.

I was referring to real life situations (which is what the thread is asking and not a maths lesson) where two sixty watt lamps won't reduce in brightness as there's one and a half kilowatts available before a six amp circuit breaker will trip. Please don't drag me further into this as the last thing I want to discuss after coming home from work is what I do for a living. There's obviously been crossed wires (lol) within this discussion but believe me when I say I know what I'm talking about on the subject. I'm not saying anything else. I'd rather talk about what's on the telly and I don't even have one.

 

[gentlegreen]

I was referring to real life situations where two sixty watt lamps won't reduce in brightness as there's one and a half kilowatts available before a six amp circuit breaker will trip.

Sorry but that's amazingly wrong for someone in the trade.

You started it.

Maybe I'll have to do it and take a photo... I don't usually buy incandescents, but I think Tesco have them for 12p ....

The only way two 60 watt lamps can emit 120 watts in series on a 240 volt circuit is if they're made for the American market.

 

[WouldBe]

Sorry but that's amazingly wrong for someone in the trade.

Correct.

The only way two 60 watt lamps can emit 120 watts in series on a 240 volt circuit is if they're made for the American market.

Or a fault develops at the substation and the voltage on the live goes up to 480V

 

[Citizen66]

Sorry but that's amazingly wrong for someone in the trade.

You started it.

Maybe I'll have to do it and take a photo... I don't usually buy incandescents, but I think Tesco have them for 12p ....

The only way two 60 watt lamps can emit 120 watts in series on a 240 volt circuit is if they're made for the American market.

That wasn't what I was arguing.

Fuck off you twonk. I'm not relating to your equation. I was trying to give advice to the thread starter about wiring in series and everything I have said is correct because I happen to maintain buildings with hundreds of lights in them.

Get back to your GCSE linking bulbs to a 12 volt battery way of thinking. I'm paid handsomely for knowing how it works in reality. I service cranes too if you want to start telling me what limit switches and dc or ac contactors do too

Come back to me though if you so wish because I'll put to you several working real life situations that you can explain to me with your science book.

 

[WouldBe]

Fuck off you twonk. I'm not relating to your equation. I was trying to give advice to the thread starter about wiring in series and everything I have said is correct[/b] because I happen to maintain buildings with hundreds of lights in them.

No your wrong.

As I said in an earlier post 'try it'.

 

[gentlegreen]

limit switches and dc or ac contactors

Hardly mind-stretching concepts.

I suggest you go on one of those "thinking outside the box" courses ...

 

[Citizen66]

I suggest you go on one of those "thinking outside the box" courses ...

I don't need to justify myself to you!

Like I said, I'm paid for what I do so perhaps you contact my employers if you're in any way unhappy but I'm not talking about this any more. It's as dull as you two clearly are. Unfortunately I have to do it to pay the bills x

 

[gentlegreen]

Sorry I don't do willy-waving.

 

[WouldBe]

Unfortunately I have to do it to pay the bills x

So did I. Vehicle electrics, helicopter electrics and even more complicated electronics.

They all follow the same basic rules of physics.

You're wrong.

 

[gentlegreen]

What scares me (given the safety critical nature of his work) is that I know the limitations of my rather piecemeal education and I know he's wrong ..... I would have known he was wrong at age 11.