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Joined: Jul 2002
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Great stuff, Scott.
Yet I ask the question.
When you are down 30V in a 120V system, that is a fair chunk of your supply voltage, I question what this was tested with.
Was this with a high-impedance meter that gave "ghost voltages"?
One other thing about fluorescent fittings, is the fact that they need to be loaded before they will output proper voltage and current.

Steve, don't get me wrong at all, I'm not looking to make you look bad, I just want to help out with some sort of a solution to the problem

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Went to check my job today. I think at this point it is obvious what the problem is. (32) (2x4) 2 tube (2x4) lay in fixures on 1 circuit, not counting 13 exit lights on same circuit, all pulling constant load. Another 7 outside emergency lights that only come on with the exit light battery when power is off. Total amps on circuit is 19 amps, on a 20 amp breaker. All lights are controlled from 8 locations. The light furthest away from the electrical panel is operating on 95.3 volts. The light I actually started working on, (on the original trip) was working at 90 volts(actually looks closer to electrical panel, but who knows how the conduit is run). From one end of the hallway to the other is 184 ft. (by the scale on prints), not counting the hallways that branch off to the front and back of building at the different entrances.
Total sq. ft. of building is 13,254 sq. ft.
As far I can tell now, all the lights are left on 365 days of the year. There are no emergency lights that stay on when the hall switches are turned off. The emergency lamps only come on when the power to the circuit goes off. Out of 13 emergency lights (2x4 layins) shown on the prints, only 8 are working. Probably the reason they leave the lights on all the time, is for security reasons. Looks like the archetect would have designed for some lights to stay on constantly. I looked at the wiring diagram for the emergency ballast, thinking that the brown leads may need to be connected for this purpose, but not so according to the Notes they include.
Voltage on the unswitched feed is 120 volts.
Voltage on the switched feed, (which controlls all the lights)ranges from 90 volts to 95 volts.
Conclusion #1: Looks like I get to schedule another Saturday trip to replace 5 emergency ballast.
Conclusion #2: Looks like "Voltage drop" is causing the low voltage through all the switches. (No feasible way to remedy except to do "major, major" dividing of the circuits and switches).
Conclusion #3: The effects of low voltage on the lights and ballast will give me more service work:)
This building is only about 2 years old.
If you have any ideas on my "conclusions" please let me know. It took me about 4 hrs including drive time
(this clinic is about 25 to 30 miles from my office).
In my opinion, the archetech made some errors and the inspection dept. that reviewed the plans missed them.
Thanks again for replies... Steve
P.S. One more question: Wondering why the emergency ballast I originally checked was causing the regular ballast not to work in the fixture, yet the other lights in the hallway that have bad emergency ballast, are still working?? Thanks again..


Last edited by sparkync; 10/29/11 04:43 PM.
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Trumpy, I checked the voltages with a "fluke meter". I double checked my meter on a receptacle outlet that had 120 volts. No problem on me looking bad. If I'm making a mistake, I'll be the first to want to correct it.
Thanks for the reply. Steve...

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Instead of "major major" dividing of the switches and circuits, can a lighting contactor be inserted such that the switches control the contactor coil and the contactor powers the fixtures? This would remove the fixture current from the switches and would require minimal rewiring.

Just unsolicited advice from a non electrician engineer.

Larry C

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I would never have believed that someone could devise a lighting circuit with a 25% voltage drop. You did a good job recognizing the problem.

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19 Amps on a 20 Amp breaker...

The circuit needs to be rewired.



Tesla
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Steve,

Just read your recent message, regarding the Lighting issues.
I will quote parts of the message with my comments.

Quote


Went to check my job today. I think at this point it is obvious what the problem is. (32) (2x4) 2 tube (2x4) lay in fixtures on 1 circuit, not counting 13 exit lights on same circuit, all pulling constant load. Another 7 outside emergency lights that only come on with the exit light battery when power is off. Total amps on circuit is 19 amps, on a 20 amp breaker.



As Tesla said above, the Circuit should be Rectified, as the Load is > 15.999 Amps, and running _Continuously_ for more than 179 Minutes, 59 Seconds.
Unless the Conductors are all #10's, this is an issue.
Poor Design and Installation is the culprit.

The 2x4 2 Lamp Fixtures would draw 64 VA each (0.534 Amps @120V). Thirty-Two Fixtures equals 2,048 VA - or 17.067 Amps @ 120V.
The Exit Signs (if they are LEDs), would draw 5 VA each, for a total of 65 VA for all 13 Exit Signs.
65 VA @ 120V = 0.54 Amps.
Base total for the single Lighting Circuit so far: 2,113 VA, or 17.61 Amps @ 120V.

Loads for the Charging functions on the Exits and the Em. Ballasts:

a: Exit Signs: 2 VA each - total of 26 VA (0.22 Amps @ 120V),
b: Emergency Ballasts: 12 VA each; total of 156 VA (1.3 Amps @ 120V).
Total of 183 VA (1.52 Amps @ 120V).

Add the Charging Loads to the Lighting Loads:
2,113 VA Lighting + 183 VA Charging = 2296 VA (19.134 Amps @ 120V)

If the Lighting was connected to a 277V 20 Amp Branch Circuit, Thirty-Two Fixtures on the same Circuit would not be a problem (I wonder if that was the original idea...)

---------------------------------------------

Quote



Total sq. ft. of building is 13,254 sq. ft.



Is the Building's Service Voltage only 208Y/120V 3 Phase 4 Wire? Seems the Footprint Area of +13K Sq. Feet would have 480Y/277V 3 Phase 4 Wire Service Voltage.

---------------------------------------------

Quote


All lights are controlled from 8 locations. The light furthest away from the electrical panel is operating on 95.3 volts. The light I actually started working on, (on the original trip) was working at 90 volts(actually looks closer to electrical panel, but who knows how the conduit is run). From one end of the hallway to the other is 184 ft. (by the scale on prints), not counting the hallways that branch off to the front and back of building at the different entrances.



It appears the Lighting Circuit runs through (2) 3-Way Switch "End Points", and (6) 4-Way Switch "Mid Points", then to the First Fixture near that last 3-Way Switch location.
If the end of the Switch Loop is at the end of the Hallway (184 Feet), the Voltage Drop at that point would be 11.51%; which would yield 106V (figuring #12 Conductors).
This is just the Switch Loop, not including the Home Run Length.
Figuring an additional 100 Feet for the Home Run (total Circuit Length from Panelboard to last 3-Way Switch = 284 Feet), the Voltage Drop becomes 17.76%.
17.76% loss from 120V = 98.69V.

The Fixture which readout at 95.3V is probably closer to the Panelboard - per total Circuit Length, than the Fixture showing 90V.
At these lengths, the Circuitry should have been at least #10's, with (2) Circuits coming in to the "Middle" of the Hallway.
Occupancy Sensors would have been a better choice for this Corridor's Lighting Controls.

---------------------------------------

Quote


As far I can tell now, all the lights are left on 365 days of the year. There are no emergency lights that stay on when the hall switches are turned off. The emergency lamps only come on when the power to the circuit goes off. Out of 13 emergency lights (2x4 lay-ins) shown on the prints, only 8 are working. Probably the reason they leave the lights on all the time, is for security reasons. Looks like the architect would have designed for some lights to stay on constantly.



I agree - there should be a few Unswitched Fixtures in this Corridor for Egress purposes (Emergency Egress without complete Outage, and Non-Emergency Egress).

The Non-Functioning Emergency Fixtures may have failed due to Heat + Voltage Drop.

--------------------------------------


Quote


I looked at the wiring diagram for the emergency ballast, thinking that the brown leads may need to be connected for this purpose, but not so according to the Notes they include.



Is this information from the Dual-Lite UFO-3AW Schematic?
I only see (1) Brown Lead, which connects to the "Charging Indicator" Lamp (Lamp Loop = Brown + Violet).
If you have a different Schematic / Ballast type, please let me know.

-------------------------------------------

Quote


Voltage on the Unswitched feed is 120 volts.
Voltage on the switched feed, (which controls all the lights) ranges from 90 volts to 95 volts.



It appears the Unswitched Lead is from the beginning of the Switch Loop (at the Home Run location), and since there is less than 240 VA (2 Amps @ 120V) Load on this segment, the Volt Loss is dramatically less.

This slightly changes my Voltage Drop Calculation, as the Load at the end of the Switch Loop is 1.52 Amps less.

--------------------------------------

Quote


P.S. One more question: Wondering why the emergency ballast I originally checked was causing the regular ballast not to work in the fixture, yet the other lights in the hallway that have bad emergency ballast, are still working??



Good question!

The Ballast you worked on may have been setup to drive the Lamps only when there is an Outage, or the Voltage on the Switched Circuit was below the Threshold for Ballast Operation.

If the Failed Ballasts were connected, so as to drive the Lamps only during an Outage, the Failure of the Ballasts would probably exclude them from the Circuit... I am not too sure, though.

Chances are these Fixtures will have several "Variations" in how they were Connected (i.e. Whom ever got the exciting task of installing the Em. Ballasts, made up some Fixtures as Switchable, and others as Normally Unlit... possibly due to a "Liquid Lunch" experience).

-- Scott


Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!
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"Chances are these Fixtures will have several "Variations" in how they were Connected (i.e. Whom ever got the exciting task of installing the Em. Ballasts, made up some Fixtures as Switchable, and others as Normally Unlit... possibly due to a "Liquid Lunch" experience)."

Sounds like the root cause of the complete lighting situation as described herein.



John
Joined: Jun 2004
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Scott...

I'd bet on multiple teams wiring up this beastie...

That certainly was the malpractice that I've witnessed in the trade.

I also agree that the EE expected a 277V circuit.

I've seen more than one installation wherein the lights are on 277 across the board -- until the EM lighting circuit! It went down to 120 VAC. In that instance it had its own EMT run -- even though the EM fixtures were in-line with 277V strips.

( Grocers )



Tesla
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Another question concerning this lighting problem. Is it "Code" to have some unswitched lighting for egress in a facility like this? I looked in the Code (old code book)but couldn't find it. Wondering if the inspector may have missed this if there is. Still trying to get my solutions together before I present them to the customer.
Thanks.. Steve

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