Craig Rochat LC
Member
- Location
- Knoxville, TN USA
I would like to know the code requirements for installing High Bay Flourescent lighting. Can you run cord? How far? Does it have to have a plug or can it be hard wired?
What is the code requirement for installing High Bay Fluorescent Lighting?
- Thread starter Craig Rochat LC
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spark master
Senior Member
- Location
- cyberspace
We done quite a few HID to Flourescent conversions. While the energy savings is there, it becomes a maintenance headache. You now have 4 or 6 times the amount of lamps to maintain.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
But whats the lamp life of the HID compared to fluorescent?
The fluorescent can be operated off of occupancy sensors or can be switched.
We had a parking garage with HID (hundreds) and there was always one or two out. Solved that problem by going to induction
The fluorescent can be operated off of occupancy sensors or can be switched.
We had a parking garage with HID (hundreds) and there was always one or two out. Solved that problem by going to induction
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Most highbay fluorescent lighting can be ordered with a 6' twist lock cord and plug so if the original install was twist loc then the swap out is easy, I favor the T-5 lamp with mirror reflector fixture as the lumen's per watt is higher then the T-8 and the light output is much higher, also using a twist loc cord and plug is nice when it comes time to replace a ballast or somthing as you just unplug it and take the fixture down (put it on hooks) and do the work on a bench at ground level.
How so?
Most quality T-5 highbay fixtures come with parallel ballast which means if one lamp goes out the rest stay lit, I have found this as well as my customers as a good advantage as a much larger area just doesn't go dark like if you loose a 400 watt HID lamp, matter of fact most don't even notice that a lamp went out, with good T-5's pushing 40k hours it doesn't happen that often either, there are also other advantages to these as they are instant on which as was pointed out motion sensor, 3-ways switching makes sense, short term power failures are not a problem anymore, this on top of the wattage savings makes for a pretty good sale.
I tend to be fond of the RUUD ones while they are a little pricy they stand behind them, and I have very little trouble with installs using them, also they sell direct which means lower cost then going through a middle man, to get prices you have to sign up to there web site though.
Last edited:
weressl
Esteemed Member
Usually replacements are done on a fixture-to-fixture basis, the new fluorescent fixtures containing 6-8 tubes for equivalent light output. Granted that replacing one bulb versus up to 8 tubes will take more time, but it it not a significant portion of the time. Group relamping is of course the most efficient way in both cases. If you're replacing MH fixtures, the life difference goes to the fluorescent advantage. The relamping cycle could be 2-2.5 longer, so overall less manitenance cost.
stevebea
Senior Member
- Location
- Southeastern PA
I agree...I did a T5 retrofit 3 years ago (1100 fixtures) which I was recently back to do some service work and the maintenence guy told me he hasnt touched a high bay yet. There were a handful of lamps out but it really wasnt noticeable.
jcbabb
Member
- Location
- Norman, OK, USA
Where are you seeing that T-5's have more lumens per watt? It is most likely true in a high-bay application where the fixtures stay warmer (which makes T-5's slightly more efficient).
You have to keep in mind that the ballasts are also part of the load equation. When you take into account the load of the system (ballast and lamp), in general T-8's outperform T-5's in the lumens per watt category(based on available published system lumens and watts from a lamp/ballast cut sheet or catalog). If you are seeing info to the contrary, I'd like to see it.
For instance, using the GE 2010 lamp and ballast catalog:
F32T8/SP30/ECO lamps are rated for 2660 mean lumens. Ultrastart PS 2-lamp T8 ballast uses 59 watts with a 1.14 ballast factor. Lumens/watt = 2x2660x1.14/59 = 102 L/W.
F28T5/830/ECO lamps are rated for 2660 mean lumens. Ultrastart PS 2-lamp T5 ballast uses 70 watts with a 1.16 ballast factor. Lumens/watt = 2x2660x1.16/70 = 88 L/W.
F54T5/830/ECO lamps are rated for 4600 mean lumens. Ultrastart HO PS 2-lamp T5HO ballast uses 114 watts with a 1.00 ballast factor. Lumens/watt = 2x4600x1.00/114 = 81 L/W.
These are specific examples, and there are many variables that can be changed, but this example is very typical.
I visit this discussion often with other colleagues in the lighting industry, and I still don't see many uses where the T5 outperforms the T8, especially when you factor in the cost of the lamps. The big exception being high bay applications where you simply can't live without the vast number of total lumens that the T5HO provides, and efficency is less of a concern.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Well here is one of the best sites that have done many in-depth studies of lighting systems, and with out any incentive to sell a product as you would have from manufactures: Lighting Research Center
Clicking on the above link will take you to one of their papers that compare the differences between T-5, T-8, and T-12, take a look at page 3 by clicking the next button at the bottom right.
I think you have you figures switched on the T-5 28 watt lamps verses the T-8 32 watts lamps, as the T-8 32 watt lamps alone would give you 64 watts for two lamps and with most ballast manufactures adding 3 watts for the ballast load per lamp you should have 70 watts with the T-8's while the RE80 a rare earth phosphor T-8's do have a 92 lm/w the RE70s' are only 89 lm/w while the T-5 28 watt lamps are 104 lm/w T-5 54 watt lamps have a lm/w of 93
Older T-8 lamps that use the RE50 or 60 a rare earth phosphor are even worse, as well as the lumen's on these lamps were in the range of 1800 to 2200 lumen's and I see many of these still at the big box stores, if your not careful some suppliers will sell you these so they can make more money as the RE70 and 80 lamps are much higher in price some places can be as high as $9.00 a lamp for them while the RE50's are around $3.00 a lamp but only have a 2k lumen's rating, so you have to be careful with what they try to sell you.
All T-5's are RE80 a rare earth phosphor and I get my lamps from Econo-Lite as they have the exact same lamps as RUDD but a little better price, last time I checked Econo-Lite web site the T-5 54 watt lamps were $3.00 a lamp but can be as high as $9.00 a lamp locally, RUUD supply's all fixtures with lamps but if I have to buy then when a customer wants spares I use Econo-Lite
I agree with you on the output of a T-5HO 54 watt as when retro fitting from 400 watt MH's with 20,000 lumen's it takes 8 lamps with T-8's high bay fixtures using the RE80 rare earth phosphor lamps, the 6 lamp T-5HO 54 watt will give you around 30,000 lumen's tapering off to 28,000 lumen's after about 10k hours which is a quite a big difference in light output and with the mirrored reflectors you will have almost 2.3 times more light then that shinning down on the work space while the T8 8 lamp will only produce around 22,000 lumen's which you can get them with the mirrored reflectors also but with the bigger diameter lamp size it does get in the way of the reflector a bit more and is not as effective, a 400 watt MH is about 480 watts with the ballast load figured in, the 6 lamp T-5HO 54 watt is about 320 watts but way more light, I have compared both the T-5s and the T-8s and have installed both in the same building just to let the customer chose which one they wanted and they chose the T-5 every time when they saw how much more light they got over the T-8's with 8 lamps, for office retro fits it hard to find a good kit to use the T-5 28 watt but I believe in time the T-5's will become more of an option used but right now because of the difference in length in the lamps and use of the mini socket with the T-5's its just not feasible to change from a T-12 to a T-5 28 watt as it is with the T-8 being the same as a T-12 without changing the whole fixture.
On other nice benefit of these newer Highbay fixtures over the older 400 watt Highbay's is the weight, I always install all my highbays with cord and twistloc's as it makes it so nice to be able to just unplug the fixture and lift it off the hook and bring it down for repair (ballast) or for cleaning, even with a lift the 400 watt MH's were still a bare to muscle down in a scissor lift or cherry picker as they were heavy and awkward with the big shell reflector, with these new fixtures it is so nice to run the scissor lift up and unplug the fixture and lay it across the railings on the lift and bring it down but depending on ones you get as some are very fragile and the reflectors can bend or dent fairly easily so you have to be vary careful with them.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
I guess I should have read a little more on T8's then I have,I still don't know why ballast manufactures have this much less wattage rating on 2 32 watt lamps when including the ballast then any other type of lamp, in most all cases except a T-8 a two lamp ballast will always show a rating that will include the wattage of the two lamps and a small ballast wattage resulting in a rating that is a few watts above the total lamp wattage, such as the rating of T-5 at 117 watts for a two lamp ballast and two 54 watt lamps.
But after looking at the specs of a couple ballast manufactures they all state a 59 watt input rating for a two 32 watt T-8 lamp ballast???? Now I am confused, if a 32 watt T-8 lamp has a 32 watt rating which is 64 watts for two, how is it that the ballast will only use 59 watts?
Also something I have now read is that the most efficient ratings of the T-8 and the T-5 systems are 18? F apart as the T-8 is most efficient at 77? F (25?C) and the T-5 is at 95?F (35?C) which does not seem like much but if you look at the output lumen's of the T-8 as the temperature rises the output in light drops off more with the T-8 then the T5 as at the point of 55?C the T-8 has fallen to about 65% of lumen's output, but the T-5 is only down to 80% which can play a role when a fixture is enclosed or in a high ambient area such as it would be up high.
Most efficiency ratings are taken at the lamps most optimal temperature so it is kind of misleading as with a 77? F optimal temperature for a T-8 which in most cases will never be operating at unless maybe in the dead of winter outside or in a cold warehouse, I would be more inclined to believe that in most enclosed fixtures it would be operating at a much higher temperature then 77?
I still stand on that a T-5 lamp is more efficient than a T-8 but it is not that much of a difference
But after looking at the specs of a couple ballast manufactures they all state a 59 watt input rating for a two 32 watt T-8 lamp ballast???? Now I am confused, if a 32 watt T-8 lamp has a 32 watt rating which is 64 watts for two, how is it that the ballast will only use 59 watts?
Also something I have now read is that the most efficient ratings of the T-8 and the T-5 systems are 18? F apart as the T-8 is most efficient at 77? F (25?C) and the T-5 is at 95?F (35?C) which does not seem like much but if you look at the output lumen's of the T-8 as the temperature rises the output in light drops off more with the T-8 then the T5 as at the point of 55?C the T-8 has fallen to about 65% of lumen's output, but the T-5 is only down to 80% which can play a role when a fixture is enclosed or in a high ambient area such as it would be up high.
Most efficiency ratings are taken at the lamps most optimal temperature so it is kind of misleading as with a 77? F optimal temperature for a T-8 which in most cases will never be operating at unless maybe in the dead of winter outside or in a cold warehouse, I would be more inclined to believe that in most enclosed fixtures it would be operating at a much higher temperature then 77?
I still stand on that a T-5 lamp is more efficient than a T-8 but it is not that much of a difference
jcbabb
Member
- Location
- Norman, OK, USA
Hurk,
The ballast factor is one of the key ingredients. It determines how much the ballast drives the lamp. A 32w lamp has a maximum load of 32w, but a 0.88 ballast will only use 0.88x32 watts, plus the ballast losses. When you compared the T-5 to the T-8, I wonder what the ballast factors were, and what relevance they had to the light output. I base most of my opinion on the math and the lighting calcs with programs like Visual. If T-5s are truly more efficient, I haven't seen it yet (for a typical office/classroom application).
As I said before, a highbay application is the best use for a T-5 because they do thrive in the warmer temperature compared to T-8's.
I need to look into the rare earth phosphor differences. That is new info to me, thanks for sharing your info and experience.
Craig Rochat LC
Member
- Location
- Knoxville, TN USA
Mike Antonelli
New member
- Location
- Fallsington, PA
Contractor
Contractor
Does any one know if a twist lock plug is required on high bay fixtures? The existing fixtures currently have 3 prong plugs that plug in the down position so they will not fall out by gravity.
I didn't want to hard wire the fixtures but adding twist locks with receptacle and plug would throw the ROI off.
Contractor
Does any one know if a twist lock plug is required on high bay fixtures? The existing fixtures currently have 3 prong plugs that plug in the down position so they will not fall out by gravity.
I didn't want to hard wire the fixtures but adding twist locks with receptacle and plug would throw the ROI off.
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