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-   -   3 Phase light problems. (http://www.diychatroom.com/f18/3-phase-light-problems-148669/)

agent99 06-30-2012 01:24 AM

3 Phase light problems.
 
I put a new single pole 15 amp light circuit on a 208v 3 phase service panel. Only 3 lights on it, but 1) the exact same NEW light bulbs burn much brighter than one on another circuit and 2) they keep burning out in a few minutes to a day being on. Very strange. I can't figure out why, please help, thanks!

I used a siemens instead of the ge breaker in a ge panel but I can't see that making a difference as there other brands of breakers in there too doing fine.

jbfan 06-30-2012 07:04 AM

Are you sure you have a 3 phase 208 service, or do you have a 240v high leg service?

Check the voltage to neutral, and i be you find out it is about 180 volts.

Remove the siemens breaker and us the correct breaker for the panel.

Speedy Petey 06-30-2012 07:25 AM

Is this in your home or a commercial setting?

I also think you have a high leg and that is where you put the breaker. If this is the case I'll refrain from commenting further as I don't want to go there.

AllanJ 06-30-2012 07:51 AM

After measuring the voltage at the breaker screw (to neutral) if that is in the 180 plus volt range (typically 208), move the breaker to a different slot where it measures 120 volts.

A high leg slot (they could be arranged one in every three slots) in a 120/240 volt 3 phase panel should be used only with a 3 phase breaker (triple wide) or a double wide breaker for a 240 volt only circuit (that does not use the neutra)l.

It would be a good idea to put a band of orange tape on each end of each hot wire connected to the high leg of 120/240 volt 3 phase systems. Orange tape is not needed with symmetric 3 phase systems with 120 volts hot to neutral for all legs and 208 volts hot to hot; red and blue tape is commonly used to identify the legs when all the wires are black.)

(Is there a standard for 120/240 volt equipment with 4 prong plugs and matching grounded receptacles where one leg may be a high leg and all 120 volt subcircuits are wired to the other hot plug prong? Or would this confuse too many amateur electricians?)

jbfan 06-30-2012 12:26 PM

Quote:

Originally Posted by AllanJ (Post 954578)
After measuring the voltage at the breaker screw (to neutral) if that is in the 180 plus volt range [color=#909090](typically 208)[/color], move the breaker to a different slot where it measures 120 volts.

A high leg slot (they could be arranged one in every three slots) in a 120/240 volt 3 phase panel should be used only with a 3 phase breaker (triple wide) or a double wide breaker for a 240 volt only circuit (that does not use the neutra)l.

It would be a good idea to put a band of orange tape on each end of each hot wire connected to the high leg of 120/240 volt 3 phase systems. Orange tape is not needed with symmetric 3 phase systems with 120 volts hot to neutral for all legs and 208 volts hot to hot; red and blue tape is commonly used to identify the legs when all the wires are black.)

(Is there a standard for 120/240 volt equipment with 4 prong plugs and matching grounded receptacles where one leg may be a high leg and all 120 volt subcircuits are wired to the other hot plug prong? Or would this confuse too many amateur electricians?)

Typo Alan?

If he has a voltage to neutral of 180 volts, that will not ne a 208 system, but a 240 volt high leg.

agent99 06-30-2012 12:45 PM

follow up
 
I am aware of the 3rd position rule in a 240 panel. It is definitely set as a 208 panel 3 hots plus the neutral. There are other single pole breakers not in the 3rd position that seem to be fine. I will try changing the breaker and report back,thanks. BTW, it is not a home, but for a small restaurant/bar but I can't see why a commercial setting would make a difference.

k_buz 06-30-2012 01:02 PM

One thing you could do is meter the voltage at the panel.

LooseSCruz 06-30-2012 02:12 PM

Quote:

Originally Posted by agent99 (Post 954762)
BTW, it is not a home, but for a small restaurant/bar but I can't see why a commercial setting would make a difference.

Because in most, if not all, jurisdictions it is illegal for anyone other than a licensed electrical contractor to perform work in a commercial setting.

andrew79 06-30-2012 02:35 PM

second thing i would do is look for an open neutral. You've got brighter lights on one leg and dimmer ones on the other. Odds are it's a shared neutral and you've got 140v or so on one leg and 70v or so on the other.

first thing i would do is call in a qualified electrician because 3 phase will bite you on the @ss if you don't know what your doing. not to mention you legally can't work on it without a license.

Speedy Petey 06-30-2012 02:44 PM

Quote:

Originally Posted by LooseSCruz (Post 954818)
Because in most, if not all, jurisdictions it is illegal for anyone other than a licensed electrical contractor to perform work in a commercial setting.

And if your area does not require licensing one should at least have the proper insurance and credentials.

Work on your own home is one thing, but work in a commercial setting is NOT DIY work.
If you have to come to a DIY message board to ask questions IMO you are NOT qualified or experienced enough to be doing such in such a setting. :no:


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