tony3phase
Member
- Location
- Seattle Washington
Do you still have to calculate industrial lighting as continuous load if motion sensors are being installed?
Industrial lighting calculations
- Thread starter tony3phase
- Start date
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- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
If the lights on on at any time for more than 3 hours than yes you would however an area like a bathroom would not need to be.
tony3phase
Member
- Location
- Seattle Washington
Thanks for the info
Thanks for the info
If you don't mind I have one other question, I'm taking my administrators exam for the 3rd time this week been doing load calculations tell going nuts. My question is the book(Mike Holt exam prep.) says all calculations should be done using nominal voltage 120, 120/240 and so on code book motor charts are 115,230 it seems to bounce around in the different practice tests I take is there some rule as to when to use one or the other?
Thank you for the help
Tony3phase
Thanks for the info
If you don't mind I have one other question, I'm taking my administrators exam for the 3rd time this week been doing load calculations tell going nuts. My question is the book(Mike Holt exam prep.) says all calculations should be done using nominal voltage 120, 120/240 and so on code book motor charts are 115,230 it seems to bounce around in the different practice tests I take is there some rule as to when to use one or the other?
Thank you for the help
Tony3phase
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
I understand your confusion, and I don't think there really is any governing rule. Motors are rated 115, 230, and 460 because they expect a voltage drop from the 120, 240, or 480 volt source. So if you are calculating the load from a 1/2 HP motor served from a 120 volt source, you can take the tabulated 9.8 amps and multiply it by either 115 or 120. Your real question is which number did the author of the test question use?
I am afraid there is no way to answer that. I use the 120 volt number as a matter of practice. That is because it gives the higher value of load, and my concern is making sure the system has the capacity to handle all the load. The best hint I can offer is to do the problem both ways, and see if one or the other, or both, answers are available as possible choices. If both answers show up, it means that the author of that question is diabolical, and you are down to a 50/50 guess.
Good luck with your third attempt. It took me two tries to pass the 01 Administrator exam. That was twelve years ago, and I do not know how much the exam process has changed in that time.
I am afraid there is no way to answer that. I use the 120 volt number as a matter of practice. That is because it gives the higher value of load, and my concern is making sure the system has the capacity to handle all the load. The best hint I can offer is to do the problem both ways, and see if one or the other, or both, answers are available as possible choices. If both answers show up, it means that the author of that question is diabolical, and you are down to a 50/50 guess.
Good luck with your third attempt. It took me two tries to pass the 01 Administrator exam. That was twelve years ago, and I do not know how much the exam process has changed in that time.
kwired
Electron manager
- Location
- NE Nebraska
That may depend on just how busy that bathroom is expected to be. If you put occupancy sensors in the restrooms at a 100,000 seat football stadium, chances are there is enough activity in there making the lights remain on for more than 3 hours during a typical game, and if they sell beer at the stadium that chance goes up quite a bit:happyyes:
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