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Discussion Starter #1
Is a ballast labeled 277V just mean max of 277 and household 220-240V range is the intended application, or is 277 some kind of industrial voltage level not found in homes?
 

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Discussion Starter #2
This is the ballast I was looking at:

http://www.1000bulbs.com/4-Lamp-T8-Ballasts/32956/

Says input line voltage is: 277 +/- 10%

Minus 10% would only put it at 250V which is less than at my house, does that mean it will work less efficiently or not at all?
 

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I believe 277v systems are normally used in commercial/industrial buildings that have 480 3-phase. I wouldn't bother with it, and just get stuff designed for normal single-phase buildings.
 

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Is a ballast labeled 277V just mean max of 277 and household 220-240V range is the intended application, or is 277 some kind of industrial voltage level not found in homes?
277V is the line to neutral voltage in a 3Φ 480V WYE system and is commonly used to power trios of 277V single phase lighting loads in buildings with the aforementioned 480V WYE system.
 

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Discussion Starter #5 (Edited)
Ok. Do they make 220-240V household ballasts? I figure if I'm going to upgrade my fixtures to T8s, might as well get ones that save me a few amps here and there because I'm being miserly with my garage power-- only 30 amps available.

Edit: found some that operate from 120-277 volt input. sweet!

http://www.1000bulbs.com/4-Lamp-T8-Ballasts/34173/
 

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The 277 ones will not work. The ballasts you see that say 120-277 may just mean 120 or 277 volts. Either way with any ballast or any appliance for that matter will consume the same power higher volatage or not, it will pull less amps
 

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The 277 ones will not work. The ballasts you see that say 120-277 may just mean 120 or 277 volts. Either way with any ballast or any appliance for that matter will consume the same power higher volatage or not, it will pull less amps SO THAT YOU CAN RUN MORE LIGHT FIXTURES ON A 20A CIRCUIT IN A WAREHOUSE, OFFICE BUILDING, STORE, ETC.
Finished the sentence for ya :D
 

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Discussion Starter #8
Yeah I hadn't thought it wouldn't cost any different but like 78 bronco was saying figured I could save a few amps since my garage only has 30 amps total capacity. I moved my compressor & air drier into the basement so it should work out.
 

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Discussion Starter #9
The 277 ones will not work. The ballasts you see that say 120-277 may just mean 120 or 277 volts. Either way with any ballast or any appliance for that matter will consume the same power higher volatage or not, it will pull less amps
I checked the spec sheet and it lists specs for 120,230,277 input voltage broken out separately, so it seems these should work for for my setup. Just need to pick up a dual pole 15A breaker...

http://www.1000bulbs.com/images/PDF/advance-centium-IS-brochure.pdf
 

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You won't be saving any amps on your panel, since your panel has 30 amps of 240 or 60 amps of 120.

The only savings you would see is that you could run 2x as many fixtures on one circuit of 240, so that could save you the cost of the conductors. Also the ballast at 240 might save a very slight amount in electrical costs since it *may* be more efficient.
 

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I removed a pile of 200 watt incandescent bulbs and replaced them with 13 watt compact fluorescents.

They are not as bright, but I'm not maxing out my electric service and the lights don't dim when the compressor kicks on or I use the lift.

Might be worth a thought.
 

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Discussion Starter #12
You won't be saving any amps on your panel, since your panel has 30 amps of 240 or 60 amps of 120.

The only savings you would see is that you could run 2x as many fixtures on one circuit of 240, so that could save you the cost of the conductors.
I'm confused. If my garage supbpanel is fed by a dual-pole 30 amp breaker, you're saying I could use a 120V device pulling 59.9 amps before it tripped? This doesn't make sense to me. I thought 30 amps was 30 amps.

If these consume 1 amp at 120V, and .45 amps at 240V, 4 of these ballasts should save me 2 amps if I run them all off 240V power right? That is the 2 amps savings, not in the electric costs, but in current usage.
 

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277V is the line to neutral voltage in a 3Φ 480V WYE system and is commonly used to power trios of 277V single phase lighting loads in buildings with the aforementioned 480V WYE system.
Correct me if I am wrong, but doesn't wye and delta just refer to how 3ph motors are wound?
 

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watts = amps x volts is the key to everything.

now you can only load a breaker up to 80% of its rating so with 30 amps you actually only have 24 amps to work with for lighting.

At 240 volt you say the ballast you are looking at is rated at .45 amps. So 24/.45=53 light you can put in.

At 120 volt you figure 24/1=24 lights you can put in.

Now the thing to remember is that no matter you use 120 or 240 a 4 lamp T8 uses roughly 120 watts. You get billed in kW/hr. So if you have 53 lights vs. 24 lights it will cost you twice as much.

As for Wye and Delta that is more about how the power is supplied to you. Quick little blurb I found that sums it up pretty well.

Delta vs. Wye Power

Wye connected power has two different voltages available. The Phase to Phase voltage is the main system voltage (typically 208 VAC or 480 VAC in the United States). The Phase to Neutral voltage is also available, and is typically used for small single phase loads (120 VAC or 277 VAC).

Delta connected power only has a single voltage level available: the Phase to Phase voltages. Other voltages can be obtained only by using step-up or step-down transformers.

Equipment designed to operate from Delta connected power, such as air conditioners or motors, can also operate from Wye connected power without a problem, since the Phase to Phase voltages are available in both systems. However, equipment that requires Wye connected power cannot operate from a Delta connected source. The Phase to Neutral voltages are not available. A special isolation transformer, designed to convert Delta to Wye, is used in this case.
 

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I'm confused. If my garage supbpanel is fed by a dual-pole 30 amp breaker, you're saying I could use a 120V device pulling 59.9 amps before it tripped? This doesn't make sense to me. I thought 30 amps was 30 amps.
This isn't the deal. The deal is you have two 120V hot wires 180 out of phase with each other (240 volts between them) and a neutral. With a 30A 2 pole breaker each phase can be loaded up to 30 amps without tripping the breaker. If you loaded up both phases with only 120 volt loads, you'd have a total of 60 amps at 120v or 7200va. If you loaded both phases with the same 240v equipment you'd still have 30A on each phase and 7200va power used, but you'd run half (for the sake of conversation) as much copper to connect the loads.



If these consume 1 amp at 120V, and .45 amps at 240V, 4 of these ballasts should save me 2 amps if I run them all off 240V power right? That is the 2 amps savings, not in the electric costs, but in current usage.
It has to do with the efficiency of the ballast. The lamps run on about 575volts. The ballast is more efficient when it changes 240 to 575 than when it changes 120 to 575. Less IsquaredR losses in the transformer, less heat.

NOW... Lets talk about something you really should think about- 240 in switch boxes can do bad things if you aren't careful. Be sure you've got your head on straight when you're working on them or it might not feel too good.
 

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I think you will find that 120-277V ballasts expect a neutral for one of the connections. A 240V ballast that takes 2 line connections is a bit of an oddity, and would cost more.

IMO, you are comparing the increased ballast cost against an extra conductor in your branch circuit.
 

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Discussion Starter #17
The spec sheet lists just 2 power inputs and does not list any provisions for a neutral. They'll be here Wed. so I 'll confirm when I hook em up.
 

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watts = amps x volts is the key to everything.

now you can only load a breaker up to 80% of its rating so with 30 amps you actually only have 24 amps to work with for lighting.

At 240 volt you say the ballast you are looking at is rated at .45 amps. So 24/.45=53 light you can put in.

At 120 volt you figure 24/1=24 lights you can put in.

Now the thing to remember is that no matter you use 120 or 240 a 4 lamp T8 uses roughly 120 watts. You get billed in kW/hr. So if you have 53 lights vs. 24 lights it will cost you twice as much.

As for Wye and Delta that is more about how the power is supplied to you. Quick little blurb I found that sums it up pretty well.
You were doing pretty well, until you tried to run the calc... :confused:

First off, you won't protect a lighting circuit with 30A, unless it's a special app, otherwise they'll be on a 20A circuit.

A Watt is a Watt. The electrical system doesn't matter one bit.

Delta - Wye transformers aren't a special deal at all, and yes, you can draw a grounded conductor from one if it is wound correctly for your desired application. Yes, there are grounded conductor systems (Dead Leg, one phase will show dead to ground. I've run across them in 240/480 as well as 120/240, not to mention high leg systems in the same voltage configurations, but that's not applicable)

In short, the number of lights on a circuit isn't going to affect your KWH consumption.


Back to ballasts - 240v is not really a common voltage here in the states. It's usually associated with a 50Hz system (check that closely when they get here)

More and more manufacturers are offering multivolt ballasts now, where you don't have to stock so many different parts, just wire it up to the correct tap (they've been doing this with HID ballasts for my entire career), or just the power wire in a 'smart' ballast that senses the incoming voltage. Seeing a 120/277v ballast for a fluorescent application isn't unusual anymore.

Confused yet? Here's the lineup for just one manufacturer that we use pretty often:
http://www.advancetransformer.com/products/fluorescent-electronic.jsp

Some days it's downright maddening to get the right ballast for the right application, in a given environment, and output (thank gawd that noise ratings are all but gone from specs with the electronic ballast)


*edit*

CPOM - the 230V on those ballasts (I just looked above, you ordered Advance ballasts) refers to 50Hz which is more common in Europe. You can leave your existing 120V circuit alone, and just retrofit the ballasts. Going to T8 lamps will reduce your existing load a little bit over the old T12's. If you want to go really high efficiency, there are other options, but they're a little more costly up front.
 

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Well first off i know 30 amp would be unusual for a light circuit however i was just giving a reference calculation. Change the numbers for whatever ampacity wire you are using.

In short, the number of lights on a circuit isn't going to affect your KWH consumption.
^ As for this well it doesn't make any sense to me. You put 1 x 60 watt keyless on a 20 amp circuit vs. 10 x 60 watt keyless on a 20 amp circuit, the 10 will cost 10x as much as the 1. If you turn all but 1 of the 10 off then it will be equal to the one. The number of lights does make a difference. Or are you trying to say something different?

And as for Hi-Leg not being applicable, well I would say 75% of the 3phase around here is Hi-Leg. Nothing like getting a call asking why a 120volt motor blew up when they wired it to their 3 phase panel :shaking:
 

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Discussion Starter #20 (Edited)
the 230V on those ballasts refers to 50Hz which is more common in Europe. You can leave your existing 120V circuit alone, and just retrofit the ballasts.
Below is what it says in the spec sheet. I think it is exactly what it says, a ballast that can handle input voltage between 120-277V and between 50-60Hz, irrespective of each other. The garage isn't wired yet so I'm going to try the 230V lighting circuit.

I have 30amps feeding my garage total (not 30 just for the lights) which means if I conserve a few amps on the lighting it would only help.

I'm not trying to save Watts & money, just available current on-tap in my garage.


2.1 Ballast shall operate from 50/60 Hz input source of 120
through 277V AC/DC with sustained variations of +/- 10%
(voltage and frequency with no damage to the ballast).
 
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