- Location
- New Jersey
- Occupation
- Journeyman Electrician
So we can assume that his calculation is incorrect?
Question on lighting MWBC calculation
- Thread starter GaTech04
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So we can assume that his calculation is incorrect?
Perhaps... perhaps not. He does state the lamps are CFL's. The ballasts are integral with the lamp, right? ...thus lamp rating includes ballast. Yet we don't know if the fixture is rated for 57W per lamp or higher (assuming 57W is not higher than the fixture's individual lamp rating).
- Location
- Massachusetts
When I read 'high bay with 57 watt CFLs' this is what comes to my mind. The ballasts are NIC.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
When I read 'high bay with 57 watt CFLs' this is what comes to my mind. The ballasts are NIC.
That's what first came to my mind, not a screw-in type replacement for an A style, Edison based lamp.
winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
Three additional possibilities:
1) You could have 6 (or more) switches, turning on alternating sets of lights for an even larger range of dimming. 1 Switch on means 2 lamps on every other fixture, then 2 lamps on every fixture...all lamps on. Is there a design requirement for 3 switches?
2) If you really want to stay with 3 switches, then you can use double pole switches rather than having a contactor. You would have 6 circuits switched with 3 switches, and at 277V you would need to be careful about which phases when to which switch (so that you didn't put 480V on a single switch)....You might even be able to use triple pole 'manual motor starters' as switches for this application, in which case you could switch different phases, and you could get more system efficiency by making sure that each lighting level was a balanced three phase load.
3) You could put OCPD downstream of your switches.
-Jon
When I read 'high bay with 57 watt CFLs' this is what comes to my mind. The ballasts are NIC.
If non-integrated ballasts are the case, for the lamp pictured, the ballast wattage is about 62W per lamp.
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WHAT HAPPENS if we use lighting fixtures on the greater than 20 amps circuits? is it banned?isnt it better since it has a larger ampacity?
Probably nothing. But it may violate the listing of the lights.
Larger ampacity isn't necessarily better (hopefully I don't have to explain that statement
)Is it banned? In residential, yes. In non-residential, no... but fixtures must incorporate heavy-duty lampholders as stated.
Other than 480's comment on probably nothing happening, the requirement leads us to believe an electrical hazard is created (result indeterminant) and perhaps a "red tag" may ensue if caught during inspection or review.
Hey guys - been gone for a bit (actually changed jobs) and just realized this topic was still going.
I'm still involved to a limited extent with my old job (and this project in particular) so I figured I would post a link to the fixtures to clear some things up: http://www.sportlite.com/UI/ProductDetails.aspx?pid=9
The model on site is the 6 lamp 57w CFL @ 277v.
I'd like to thank everyone for the help on the topic, we might actually just go with 6 switches (#1 of winnie's suggestion) for a wide range of dimming.
I'm still involved to a limited extent with my old job (and this project in particular) so I figured I would post a link to the fixtures to clear some things up: http://www.sportlite.com/UI/ProductDetails.aspx?pid=9
The model on site is the 6 lamp 57w CFL @ 277v.
I'd like to thank everyone for the help on the topic, we might actually just go with 6 switches (#1 of winnie's suggestion) for a wide range of dimming.
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