stevemechanical
Mechanical
- Mar 25, 2004
- 47
can a 120/277 volt compact fluorescent light fixture be installed in a 120/208 volt system?
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120/277 volt light fixture 3
- Thread starter stevemechanical
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Senselessticker
Electrical
Unless this is a trick question...I think davidbeach answered it.
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Skogsgurra
Electrical
davidbeach
Electrical
Skogsgurra, The ballast will have two hot leads, one for 120v and one for 277V (use on a 480Y/277V system) plus a neutral, cap off the unused lead. The 120V can come from a 120V single phase, from one phase of a 120/240V single phase, from one phase of a 208Y/120V, from one of the two 120V phases of a 240/120V delta, or from any other connection that provides 120V (like that 120V delta used on submarines).
Skogsgurra
Electrical
That's neat! Never seen that over here. We always install phase-neutral. You learn every day...
Gunnar Englund
Gunnar Englund
Sadly we have that same 120V delta on trains too.
Keith Cress
Flamin Systems, Inc.-
Keith Cress
Flamin Systems, Inc.-
davidbeach
Electrical
Keith, that's interesting. Would the 120V delta be something in that is still being installed, or does that go back before the Amtrak 480Y/277V HEP system?
Hi David! Naw, old train stuff not the H.E.P. I didn't know subs had some of that too. Most interesting!
Keith Cress
Flamin Systems, Inc.-
Keith Cress
Flamin Systems, Inc.-
Most new generation electronic ballasts will have the input voltage sensing circuitry which internally selects the volage setting depending on the incoming voltage. they will self select the correct voltage from 120V to 277V, phase to neutral. There are still many multi-tap ballasts which will have several "hot" leads, and a neutral, it is just a matter of selecting the lead which matches your system voltage and capping off the rest.
Submarines use 120V ungrounded delta. They do this for battle field relability. In case there is a single phase ground fault during an operation (ie battle)the system can still operate, just as a corner grounded delta.
Ian Rines
Harris Corporation
Palm Bay,FL
Ian Rines
Harris Corporation
Palm Bay,FL
SDestimator
Electrical
To expand on the "new generation" ballasts:
Most major lighting manufacturers (Lithonia, Columbia, etc.) have made the transition to what are known as mVolt (for multi-volt) Ballasts in the last few years. these ballasts can have pretty much any standad voltage up to 277v applied to them and they will function properly.
Most major lighting manufacturers (Lithonia, Columbia, etc.) have made the transition to what are known as mVolt (for multi-volt) Ballasts in the last few years. these ballasts can have pretty much any standad voltage up to 277v applied to them and they will function properly.
SDestimator
Electrical
Errk.
Correction: mVolt ballasts are designed with single phase power in mind (a hot and a neutral). As 208v power is "two phase" I don't think they will function properly.
Here is a link to a GE spec sheet:
Correction: mVolt ballasts are designed with single phase power in mind (a hot and a neutral). As 208v power is "two phase" I don't think they will function properly.
Here is a link to a GE spec sheet:
Anti-correction SDestimator; From the ballasts point of view they would still think that was a single phase.
Keith Cress
Flamin Systems, Inc.-
Keith Cress
Flamin Systems, Inc.-
davidbeach
Electrical
The only distinction between phase & neutral and two phase conductors is that in the phase & neutral case the neutral conductor is near ground potential and in the two phase conductor case neither of the conductors is near ground potential. Poorly designed electronics could be expecting one conductor to be near ground potential. Well designed electronics would not have any way of knowing/would not care how the voltage was derived, only the magnitude of the voltage.
SDestimator
Electrical
Truthfully, I do not know for sure.
I would be hesitant to put an mVolt ballast on a 208v circuit though, as all of the ones I have seen state 120-277 with no mention of 208v.
I would be hesitant to put an mVolt ballast on a 208v circuit though, as all of the ones I have seen state 120-277 with no mention of 208v.
Skogsgurra
Electrical
SDestimator
Electrical
Possibly. The literature linked above does say they can be used on voltages 108-305, but the thing that makes me leary (without ever having tried it) is the phase/neutral phase/phase difference.
Standard commercial power in the US these days is pretty much all either 480-277 or 208-120 3 phase 4 wire wye connected. This makes both 120v and 277v phase/neutral whereas 208v is phase/phase.
When they say 120-277, they could be indicating they are designed for either of the commonly used Flourescent Lighting voltages, not that they are good for a range of voltages.
Standard commercial power in the US these days is pretty much all either 480-277 or 208-120 3 phase 4 wire wye connected. This makes both 120v and 277v phase/neutral whereas 208v is phase/phase.
When they say 120-277, they could be indicating they are designed for either of the commonly used Flourescent Lighting voltages, not that they are good for a range of voltages.
Skogsgurra
Electrical
That would be contrary to all logic and every standard notation I know of. A ballast is not internally tied to any ground and should be designed to accept being run from phase/neutral or phase/phase.
In the Land of Lawsuits, there should be a large waiver or caveat if that wasn't the case.
Gunnar Englund
In the Land of Lawsuits, there should be a large waiver or caveat if that wasn't the case.
Gunnar Englund
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