Lighting as a continuous load

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Strathead

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I did a search prior to starting this thread and didn't come up with anything, but it could have been discussed before.

I am inclined not to treat 99% of lighting loads as continuous when calculating today. In a typical office in Florida, occupancy sensors are required throughout which means lights will not remain on for more than 3 hours continuously in most cases. Secondly, unless you are using 220.12 Exception No. 1 (and likely even then) the actual lighting load is going to be less than the lighting load per table 220.12. I would contend that you could apply the continuous load factor prior to comparing your load to table 220.12. So, if your LED load less than 80% of the table load, then it is still under the table load and the va per foot per table 220.12 could be used without applying the load factor.

What do you think?
 
Are you allowed to take into consideration where the lights are? A place normally occupied will certainly be continuous. Storage rooms and stairways probably not, but the latter has other requirements, too. It depends on the building and its usage. And the powers that be aren't too keen on you making your own decisions about what's right and wrong.

After all, in lieu of occupancy sensors, we used to just use signs at the switch that reminded you to turn the lights off as you leave. And people obey signs. :lol:
 
MAC702 said:
Are you allowed to take into consideration where the lights are? A place normally occupied will certainly be continuous. Storage rooms and stairways probably not, but the latter has other requirements, too. It depends on the building and its usage. And the powers that be aren't too keen on you making your own decisions about what's right and wrong.

After all, in lieu of occupancy sensors, we used to just use signs at the switch that reminded you to turn the lights off as you leave. And people obey signs. :lol:
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Everything you say is correct and not only are you allowed you are basically required to consider where the lights are. There are few people who get too involved in the minutia of load calculations, similar to voltage drop on a branch circuit. We try to use rules of thumb wherever we can. That is more what i am getting at. A rule of thumb. Use the va per foot from the table and don't add for continuous because the actual load is often far less than the table load. When the actual load is close or above then you add the continuous factor when applicable.
 
One thing to remember about continuous loads is that by definition it's the maximum load on the circuit for more than 2 hours 59 minutes and 59 second hours. So that means that you would be anticipating that every light on the circuit was on at 100% output for 3 hours or more. Add one light in a storage room that won't be on for 3 or more hours while all of the other lights are on at the same time and in all likelihood it is no longer a continuous load.
 
I am inclined as well, but you need to have 220 behind you if you are challenged. Table 220.42 offers you demand factors for certain occupancies, but if you fall into the "All Others" you need to have some other excuse.
 
always used to wonder about it because a baptist style church would always meet the continuos duty for lights because of how long the service is, but they only hold the service and bible study once per week...
Saw a Catholic chirch get by the same requirement, though they did three services per sunday... because they only had lights on for 90 minutes per time... then lights were off for a half hour... inspector deemed them as not on enough at any time to be considered continuous.. yet they were on more each sunday than the baptist churches...

I always figured it was a penalty on non catholic churches that caused it... But later I read the codes and saw that the way it is interpreted is kinda like reading the bible... on one day you see it one way, on another day the other guy sees it another way...
 
Adamjamma said:
always used to wonder about it because a baptist style church would always meet the continuos duty for lights because of how long the service is, but they only hold the service and bible study once per week...
Saw a Catholic chirch get by the same requirement, though they did three services per sunday... because they only had lights on for 90 minutes per time... then lights were off for a half hour... inspector deemed them as not on enough at any time to be considered continuous.. yet they were on more each sunday than the baptist churches...

I always figured it was a penalty on non catholic churches that caused it... But later I read the codes and saw that the way it is interpreted is kinda like reading the bible... on one day you see it one way, on another day the other guy sees it another way...
Click to expand...
The code does not differentiate. The AHJ may somehow change the code, although they are not supposed to, but the calculations to determine service size is pretty straight forward, no matter what type of Church.
 
Adamjamma said:
always used to wonder about it because a baptist style church would always meet the continuos duty for lights because of how long the service is, but they only hold the service and bible study once per week...
Saw a Catholic chirch get by the same requirement, though they did three services per sunday... because they only had lights on for 90 minutes per time... then lights were off for a half hour... inspector deemed them as not on enough at any time to be considered continuous.. yet they were on more each sunday than the baptist churches... ...
Click to expand...

Wires do not care how often they are heated, only for how long each time. It's a heat dissipation issue, nothing more.
 
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