View Full Version : ELECTRICIANS! Need help with 277 volt wiring


77RS
05-02-2007, 12:07:54 AM
I've got fifteen new 277 volt light fixtures that i bought at an auction to put in my up and coming paint booth. I bought them loaded with bulbs and also got a carton of new bulbs for a total of $15. Great deal, right? Well they won't be worth .02 if I can't use them. :confused: Can I wire a 277V curcuit from my breaker?

Thanks!
Daniel

Rick WI
05-02-2007, 12:17:26 AM
Those are setup for a facility that has 277/480 volt 3 phase service. That's 277 to ground and 480 phase to phase (hot to hot). You have, in your house/garage, 120/240. 120 phase to ground and 240 phase to phase.

No way to get a 277 volt ballast to strike a lamp at 120 volts.

Check the ballest wiring diagram if they give you any alternatives. All ballasts have diagrams on them.

77RS
05-02-2007, 12:25:03 AM
Check the ballest wiring diagram if they give you any alternatives. All ballasts have diagrams on them.

:confused: LOL never thought of that. They're still in the boxes they came in.

damn Rick, you must be about 1000 yrs old. You know something about everything! LOL No joke man, I read a lot of your posts and you're really pretty sharp about stuff. Thanks.

JJFarmer
05-02-2007, 12:28:24 AM
You can use the fixture, just change the ballast to a 120v. Check Ebay for a buy on the ballast.

Rick WI
05-02-2007, 12:28:49 AM
I was an industrial engineer for a utility for 15 years.

I have seen the bowels of a lot of large dumb companies over those years.

Rick WI
05-02-2007, 12:33:48 AM
What sucks with fluorescent fixtures is it's cheaper most of the time to buy the whole fixture versus buying replacement parts. At list for this quantity of fixtures. You'll pay a pretty good price for what I'd assume you want for ballasts; 8 foot, T96 HO's. Around $40 bucks or so.

Todd80Z28
05-02-2007, 12:40:07 AM
They might strike OK with 240V.

77RS
05-02-2007, 12:43:59 AM
Uh oh..... I think I see 15 fixtures headed for Ebay in my near future.

I am going to check out the ballast cost though. Someone actually gave me 2 ballasts this weekend that I can use. Only need 13 more :)

PS: Do any of the home improvement places sell the 277's? May be able to get them to do a trade with me. they're still in unopened cartons.

77RS
05-02-2007, 12:49:06 AM
They might strike OK with 240V.

I've wondered that as well. Won't hurt anything to try, right? i'll just hook one up to my 240 outlet.

JJFarmer
05-02-2007, 06:48:02 AM
Won't the lower voltage have them running hot if it works at all?

77RS
05-02-2007, 07:15:28 AM
Won't the lower voltage have them running hot if it works at all?

http://77rs.homestead.com/dunno.gif don't know... will soon find out. Ignorance is bliss!

akcamaro
05-02-2007, 07:51:56 AM
grab a fire extinguisher.

kik_start
05-02-2007, 07:56:50 AM
they require a nuetral on 277, 240 will not work. 240= 120 x 2

John Wright
05-02-2007, 07:59:24 AM
They really stink when they get hot........

Todd80Z28
05-02-2007, 08:39:21 AM
they require a nuetral on 277, 240 will not work. 240= 120 x 2Phase to neutral is how you get 277V out of a 480V Y-connected 3-phase setup. I'm not following? Are there multi-phase line to neutral hookups on one fixture?

kik_start
05-02-2007, 08:56:27 AM
no... I'm just saying single phase 277 and single phase 240 are two different animals. It will not work.

Todd80Z28
05-02-2007, 09:06:52 AM
Voltage is voltage. 240V phase-phase or 277V Phase to neutral shouldn't make a difference. The 37V deficiency might not turn the light on, but otherwise, it shouldn't matter. Unless the ballast is internally tied to ground on the neutral side, which would be dumb (and dangerous).

tom3
05-02-2007, 09:19:46 AM
Be an interesting experiment. Don't stand in a puddle when you do it though.

Rick WI
05-02-2007, 09:28:03 AM
Todd, you have a hot lead and a neutral coming off the ballast. For standard 240V house current you need the two legs of the 120 to make 240. You can't tie these together onto the hot lead coming off the ballast as that will be a dead short.

It's all in the transformer and how it's wound. 240 single phase transformers at your house are totally different from 277/480 volt transformers at an industrial location.

Voltage is voltage, but voltage to ground is what we are talking about.

kik_start
05-02-2007, 09:30:52 AM
Three types of electricians...
One wire... hook it up
Two wire... burn it up
Three wire...BLOW IT UP!!!!

and those who can't spell, hahahah

rgearhead
05-02-2007, 10:21:47 AM
please viedo tape if you chouse #3...........lol

Todd80Z28
05-02-2007, 10:55:49 AM
Todd, you have a hot lead and a neutral coming off the ballast. For standard 240V house current you need the two legs of the 120 to make 240. You can't tie these together onto the hot lead coming off the ballast as that will be a dead short.

It's all in the transformer and how it's wound. 240 single phase transformers at your house are totally different from 277/480 volt transformers at an industrial location.

Voltage is voltage, but voltage to ground is what we are talking about.
Perhaps I didn't clarify my point-

Two legs of the house supply are 240V, when measured from one to the other. Therefore, you tie one leg/side of the breaker panel to the "hot" on the light, and the other leg/side of the breaker panel to the "neutral" on the light. You now have 240V supply to the light.
As I noted before, you should first make sure that the "neutral" line on the light isn't grounded to the case. A simple resistance check white wire to case screw will show you this. If it's 0 ohms, don't hook it up as I've stated, because you'd likely get shocked off the case. But, having neutral tied to ground within the light would be a "dumb" design, IMO- you NEVER want the ground carrying any current (which neutral does in order to complete the circuit).

This is how 240v electric stoves, water heaters, and dryers (i.e. nearly all residential) are wired. I'm not proposing something that isn't being done.

That better?

Rick WI
05-02-2007, 11:17:24 AM
[QUOTE=Todd80Z28]
This is how 240v electric stoves, water heaters, and dryers (i.e. nearly all residential) are wired. I'm not proposing something that isn't being done.


Yes you are. You are proposing to wire up a ballast that is designed for phase to neutral connections and hooking it up phase to phase.

rgearhead
05-02-2007, 11:26:37 AM
this is like the whole pnumatic PVC thing all over,,,,,,,,,,,

Todd80Z28
05-02-2007, 08:11:44 PM
Yes you are. You are proposing to wire up a ballast that is designed for phase to neutral connections and hooking it up phase to phase.What does that mean? "Designed" for neutral? Are you saying that the neutral and ground are tied together within the ballast? If that's not true, electrically speaking, someone is going to have to show me a difference.

I don't do residential for a living, but I play with electricity. A lot. 480, 208, 120, 100V systems.

Some of these style of lights are set up for multi-tap, so you can select the voltage you have. You might look and see if this can be done.

Rick WI
05-02-2007, 08:21:47 PM
It is a series circuit. You can't hook two phase wires to the hot and neutral connections in a ballast, it will create a dead short. Boom

This isn't like hooking up a motor. Think of your dryer. You have the two hot legs going to the motor to give 240 volt BUT you don't have two hot legs going to the control circuit, only one hot leg and a neutral.

Sure there are multi tap ballasts, those taps simply tie into the coil windings on the primary side of the transformer to give you correct operating voltage on the secondary side of the windings to strike and run the lamp.

kik_start
05-02-2007, 08:32:03 PM
This is how 240v electric stoves, water heaters, and dryers (i.e. nearly all residential) are wired. I'm not proposing something that isn't being done.That better?

All heating elements are single phase. The voltage rating does change and depends on how they are connected together determines what voltage or phase you can connect to them. Y^

tom3
05-02-2007, 08:36:46 PM
Hook one up and see what happens, worth a dollar (fixture cost) to find out. I'm betting it won't light.

Todd80Z28
05-02-2007, 08:56:53 PM
It is a series circuit. You can't hook two phase wires to the hot and neutral connections in a ballast, it will create a dead short. Boom

This isn't like hooking up a motor. Think of your dryer. You have the two hot legs going to the motor to give 240 volt BUT you don't have two hot legs going to the control circuit, only one hot leg and a neutral.

Sure there are multi tap ballasts, those taps simply tie into the coil windings on the primary side of the transformer to give you correct operating voltage on the secondary side of the windings to strike and run the lamp.Maybe I'm not understanding something particular about these lights? Series circuit? Are you talking multiple bulbs on one ballast?

Dead short means no resistance between two points- i.e. they are at the same potential. In your home wiring, that is not the case. The two hots are 180° out of phase- i.e. directly opposite one another. The supply to your home comes off a 240V center-tapped transformer, with the center tap being neutral. You could call one leg 120V, and the other -120V, although that wouldn't be correct in reference to AC.

In the dryer, the heating elements are run using 240V. The two legs are hooked to opposing ends of the heater- a simple series circuit. No dead short, for these two supplies are equal and opposite (in reference to neutral).

http://groups.msn.com/Appliantology/dryers.msnw?action=ShowPhoto&PhotoID=316

I don't know what else to say. The circuit needs a difference in potential- i.e. voltage- to work. 240V may not be enough, and the use of a leg on the neutral line may put voltage on the case (shock hazard, as I noted), but the concept is solid. The absolute level of voltage with respect to neutral is irrelevant, it's the difference that counts.

EDIT- someone send me one of these, and I'd be willing to give it a go. Videotaped.:)

Todd

a73camaro
05-02-2007, 09:01:57 PM
Agree with Todd80Z28 - if the neutral is not connected to the light fixture, and the neutral is an insulated wire, go ahead and try it. But 240 is 87% of 277.

Rick WI
05-02-2007, 10:55:40 PM
Hell no the neutral is NEVER connected to the light fixture. It's a current carrying conductor. It takes the current from the hot 277 leg and pulls it back to the service panel then back to the transformer at the utility, where it is bonded to ground at both points.

Maybe dead short is not really the right phrase. Hook 120 to both ends of the ballast and it will light up like a christmas tree inside the metal clad housing, for about 2 seconds, then smoke the potting material, burn up the coil and stink.

Todd, there are no multiphase taps in a ballast. The reason is all ballasts are single phase. Voltage is a function of the transformer windings in the utility transformer. In a Y type service each point of the Y is a phase. Take any two points and between those you will either have 208 or 480. Where the Y intersect between the ends, bottom of the V, is the center tap for the neutral that splits the windings in the transformer giving you either 120 or 277. Standard, typical, 3 phase Y service then is either 120/208 or 277/480. I'm sure there are oddballs out their but those are the basic secondary service offerings.

You can have ballasts that are setup to run on various imput voltages but the type I highly suspect in this case will only work on 277, that is 277 into one side of the ballast and a neutral connected to the other side.

Marks71BB
05-02-2007, 11:44:39 PM
In a poly phase distribution system you have three current carrying conductors 120 degrees out of phase with each other. with 220/110v you have two conductors 180 degrees out relative to each other.
two types of three phase circuits are in the distribution/transmission system with the higher voltage circuits being delta in which case none of the current conductors are referenced to a neutral or ground. more common distribution sytems around are the wYe circuit in which case you have 480/277 or 208V. 480 refers to the net sum of all three legs 277 from the potential between two legs or 208 from any one leg to ground (neutral in most cases).
In any case. Voltage( a/c current being the discussion d/c another animal alltogether) is Voltage.. Potential for current to flow from a - to a + alternating directions of the path of travel. Other than the frequency (hrtz) it dosent matter the source a 240 potential will likely cause the 277 ballast to work because none of the current carrying conductors should ever meet ground causing a short.

High voltage is nothing to play with but a lil experimentation when done safetly can be fun;)

Try the 277 lights with 240v and you will likely find they just have a lower wattage output.

Rick WI
05-03-2007, 01:14:07 AM
On a typical 277 volt ballast you have two conductors coming out of the ballast on the line side, a black and a white. Hot and neutral. How are you going to get 240 volts onto the black/hot conductor out of a single phase 120/240 V panel?

Are you suggesting to tap the black and the white each with a leg of 120? You don't think that will burn up the transformer in the ballast?

davidpozzi
05-03-2007, 01:37:44 AM
Years ago someone gave me a bunch of 277v lights like that. I wired 6 or 7 of them to 220 single phase and they worked for garage lighting. BUT they had 4' long tubes and seemed to not last very long. There were two ballasts per unit with four 4' tubes. With all those ballasts, there was often one that was in need of replacing.

I eventually replaced them with 8' long two tube fixtures and the bulbs last a LONG time. If someone offered me lights like that, I'd never do it again, I spent way too much on replacement ballasts and bulbs over time.
David

Marks71BB
05-03-2007, 01:56:11 AM
You don't think that will burn up the transformer in the ballast?
Nope, it is less voltage than the ballast is designed for but just not as efficient.

Todd80Z28
05-03-2007, 08:47:53 AM
How are you going to get 240 volts onto the black/hot conductor out of a single phase 120/240 V panel?You don't need a full 240 on the hot. In a home setup, you're putting 120V on the hot, and 120v inverted on the neutral. So, 120V - (-120V) = 240V. The white wire is labeled neutral for ease of hookup.

To the light, the difference between the house 240V and the industrial 277V is 37V, nothing more. David noted a high failure rate at 240V with these setups- maybe that was due to the 37V deficiency making the ballast work harder?

a73camaro
05-03-2007, 10:23:25 AM
Or the starter circuit not getting the correct voltage/signal...

Luv70's
05-03-2007, 12:22:04 PM
Rick WI, you are 100% correct, I dont think everyone else gets what you are trying to say. You CAN'T take L1+L2 and join them together ( or at least not for long to the same power point ) L1 to ground is 120v, L2 to ground is 120V, L1 to L2 is 240V. This is what Rick WI is saying. That lamp ballast is a 2 wire set up, to get 240v to it you would have to connect L1 and L2 to the same point and the nuetral on the other wire. WONT WORK!

Todd80Z28
05-03-2007, 06:42:03 PM
Rick WI, you are 100% correct, I dont think everyone else gets what you are trying to say. You CAN'T take L1+L2 and join them together ( or at least not for long to the same power point ) L1 to ground is 120v, L2 to ground is 120V, L1 to L2 is 240V. This is what Rick WI is saying.This part is correct. That lamp ballast is a 2 wire set up, to get 240v to it you would have to connect L1 and L2 to the same point and the nuetral on the other wire. WONT WORK! This part is not.

We've covered this. I'd be willing to lay down big money on it.

Marks71BB
05-03-2007, 08:22:33 PM
You don't need a full 240 on the hot. In a home setup, you're putting 120V on the hot, and 120v inverted on the neutral. So, 120V - (-120V) = 240V. The white wire is labeled neutral for ease of hookup.

To the light, the difference between the house 240V and the industrial 277V is 37V, nothing more. David noted a high failure rate at 240V with these setups- maybe that was due to the 37V deficiency making the ballast work harder?
^^^what he said

77RS
05-03-2007, 10:03:11 PM
OK guys, all of this is way over my head. I appreciate all the input.

I don't even understand what some of you guys are talking about, which lets me know that I just need to stay away from electricity :confused: I think I'll just try to off these light on to some industrial place for a few bucks and go buy something I can work with. :)

Luv70's
05-04-2007, 07:24:58 AM
I'll be there for the test, and by the way I dont accept checks;)

Phil G
05-04-2007, 11:12:39 AM
I'm a ME, not a EE. I know my way around single phase and 3-phase, but when you start mixing and matching I'm lost.

I'm too lazy to dig out my old textbooks so you guys are on your own with this one (although I DO run my 220/240V compressor off the dryer circuit and have for 20 years)...

YMMV