# High Bay conversions to Corn Cob or Star LED LAMPS



## macmikeman (Jan 23, 2007)

I have to put together a bid to do roughly 50 in a large warehouse. It's cluttered but the tenant assures me the areas will be cleared prior to my operation, which I intend to get solid in contract along with a fee for time lost if they slack off on me. The thing I'm looking to nail down is how much time to average the conversion per fixture , considering I will be using a scissor lift to get up to the 18 feet height and probably disassemble and reassemble on the lift itself. I've done a few on rare occasions before , but only like one at a time kind of thing, so I don't exactly trust my time estimate and am looking for others . I was thinking in the area of 30 minutes per fixture? (not including navigation from fixture to fixture on the lift, I have a solid number for that task). How about it? Any opinions?


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## MHElectric (Oct 14, 2011)

Depends how easy it is to get to the ballasts, Disconect them and then straight wire the sockets. 

We did a show room a couple years ago with low hanging MH lights and it probably took us 30-45 minutes a piece working off 12ft ladders. We also had to move stuff around though.


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## BillyMac59 (Sep 12, 2019)

Access to fixtures and manpower are critical for timing. As a factory electrician, building lighting has always been part of the job. I've found if two guys work at it, it went faster. Start by bringing two units down and convert them. Once one is done, one guy goes up at third location with the rebuilt unit, disconnects the old, installs the rebuild and back to the floor. If timing is right, the second guy has the second lamp rebuilt by now. They swap units and repeat the sequence. I don't know what your manning level is like but in most places I've worked, a second guy is mandatory as "ground man" - safety rules. Kill two birds with one stone and have the ground guy rebuild fixtures as well.


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## Southeast Power (Jan 18, 2009)

I think if you are working alone and you only have an 18’ ceiling height, you are going to pick up a significant efficiency on the second half of the first day.
That said, you will need the lift for a solid week rental. Call to have it picked up late Friday, use the two day weekend for any rework if it goes really bad.
The lift for a week
40 man hours
$300 misc materials.


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## joe-nwt (Mar 28, 2019)

I have done some. 30mins might be a tad skinny depending on the fixture. Some ballasts can be bypassed by simply accessing the wiring, but I've had some where the transformer itself had to be pulled to get at the socket wires. I always remove the ballast completely but I know some guys leave the disconnected ballast in the fixture. Not sure what your intent is.


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## kb1jb1 (Nov 11, 2017)

Did you price out the cost of changing the complete fixture? Corn cob lamp about $80.00 +/- vs a new light $130.00+/-. I found that the cob type do not last as long nor are they as efficient as an LED fixture. I usually go right to the new fixture. It all depends on how the old lights are mounted and wired. Also the condition of the luminair. Are the lenses yellowed or cracked? Cleaning the fixture. Is the wiring dry and burnt? You cannot get a 400 watt MH equivalent unless the luminaire uses a M37 lamp. The reduced envelope 400 watt ( ED28) has no equivalent.


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