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I am a DIYer and have made pendant/ chandeliers before with great success but I may be over my head with this one...

The question is boiled down to this: is the current wiring I have adequate for the job and do dimmers have an effect on the wire load?

Here is why I ask this question: I have started a chandelier project that has 41 vintage 40 watt incandescent bulbs. (40 watt bulbs were the lowest I could find for the style i wanted.) This will be on a dimmer to reduce the light output of 1640 watts of course! i have figured the amps are 14.9 at full power but can't find any answers about the affect dimmers have on amps if any.

This circuit includes five high hats with bulbs that I'm guessing are about 100 watts but we are prepared to change to LEDs so the added amps will be marginal.

My research suggests that amps in this set up are just about where they should be for a circuit with a 20 amp breaker. What I can't figure is if the wire is adequate. As far as I can tell the wire from the dimmer switch to the fixture is 16 gauge solid copper probably rated for 110 degrees(?) It is a 15- 20 foot run from the dimmer. Right next door (before the dimmer) is the switch for the five high hats. before that i assume the line runs direct from the breaker box for say 40-50 feet and I'm guessing it's probably the same gauge wire there.

So, in the interest of not burning my house down, can anyone tell me if the wiring is adequate and if dimmers reduce amps too?

Many thanks in advance!

PS. I don't think this is relevant to my problem but I figure i will mention it. I plan to use or fashion a power distribution set up where all hot wires go to one bank and all neutral go to another.

on

off lutron 2000 w dimmer

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  • 1640 Watts chandelier, wow! You'll be able to fry a chicken near this thing! – Dmitry Grigoryev Sep 30 '15 at 22:50
  • Dimmers not quite reduce "amps" but do decrease voltage that in turn decreases current flowing through the load. However I am seriously in doubt whether you can find a 15+ amps "dimmer" anywhere nearby. Unless you are willing to try the Scariac, of course. :D – Victor Sep 30 '15 at 23:09
  • 41 bulbs! Holy smokes! Think about wiring 2, or 3, or 4 bulbs in series to cut the power back a bit, instead of wiring all 41 up in parallel. – Chester Kustarz Oct 23 '16 at 23:49
  • There should only be this many lights if you live in a palace, Be ready for people to laugh. – DMoore Feb 25 '17 at 6:57
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For North American AC wiring, #14 wire is used on 15 Amp circuits, and #12 for 20 Amp. You will need #12 wire, and a 20 Amp breaker to feed your chandelier. If you could break the chandelier lights into two groups, you could use two 15 Amp circuits, and would have an easier time finding dimmers to control it.

A dimmer will reduce the effective current when the lights are dimmed, but I think the Electrical Code will require the breaker and wiring to be suitable for the maximum (full brightness) load.

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What you have to realize is the chandelier needs a dedicated circuit. That means nothing else can be on the same breaker.

A #12 AWG straight to the panel with a 20 Amp breaker will be sufficient.

Likely the existing circuit is shared with other lights and outlets, and ignoring this is just a problem waiting to happen.

Also, the fixture wire itself should be at least #14 Awg. Anything smaller and you're in violation of NEC article 402.5

Some dimmers do decrease the load but even at the lowest intensity is just a 40% reduction. Remember, dimmers get hot for a reason and that is the energy being displaced as heat. Dimmers do increase the life expectancy of bulbs but that is about it. And yes they do make 2000 Watt dimmers.

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You do not state your location, but in the US this would require a dedicated 20A circuit using #12 wire. I am not sure about Canada, but I believe they require a maximum 15A circuit for residential lighting, so this fixture would probably not even be legal to use.

You would require a 2000 watt dimmer. They ARE available, but are very limited. They would usually require a 2-gang wall box and typically cannot be ganged with other switches or dimmers, at least without derating.

Lutron would be the likely brand for this. Here is a spec page for the most popular version: Lutron Nova dimmer

The model number would be T-2000

To address your amps question, yes, in an indirect way dimmers do reduce the amps drawn on a circuit, but this has no effect on circuit design. The circuit would need to be designed for full load use.

  • I'm in the US. Florida. I know there is a 20A breaker on the circuit but the wire I made a guess at with a pair of electrical cutters because there isn't much wire exposed from the ceiling. Thanks for the info! – Jonase Oct 1 '15 at 21:56
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Since you would certainly never run all these bulbs at full power, consider using an autotransformer to step down the voltage. Because incandescent bulbs act like resistors when lit, the current will fall in proportion. Since watts = volts * amps, power will fall in proportion squared.

Reducing the power would make the bulbs last much longer.

The beauty of the autotransformer is it is very efficient at power conversion. So input current (@120V) would fall in proportion to power used; i.e. squared. This quickly gets you inside the legal limits for circuits.

For instance: suppose you use an autotransformer to step down 120V** to 100V. Current will drop in proportion, from 13.7A to 11.4A (@100V). Power will drop to 1140 watts, quite a drop! The autotransformer will fix it so you're drawing at 120V, and 1140W is only 9.5 amps. That's well within the 80% limit on a 15A circuit.

Since the autotransformer is built-in and can't be overridden, you would only have to provision power for the 9.5 amps.

  • A stepdown to 90V would yield 922 watts.
  • A stepdown to 80V would yield 728 watts.
  • A stepdown to 70V would yield 558 watts.
  • A stepdown to 60V (half voltage) would yield 410 watts (quarter power).

You could also use a variac, a variable autotransformer, for wide range dimming. You could limit the travel of the variac so it can't go to 100%.


**Electrical power is actually 120V. "110" is a slang term for power, which reflects what the voltage was in the 1920s when mains power was first widely marketed to common citizens. They've given it a few bumps since then.

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