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Standby Generator 500KVA Gen Room size. (QS about Clearance)

V

VENgineer

Member
Location
Miramar Fl
Occupation
Electrical Engineer
Hello, good afternoon.
Could anyone help me with the following?

I am designing a system in which I need a 500KVA Diesel Generator. I have been looking through the codes, and I can't find anything about the required clearance for the generator when installed indoors.
For outdoor or detached buildings, I know it has to be at least 5 feet away from any window, door, or access.
But for indoor installations, I think this doesn't apply. So, I have a question: is a 3ft clearance required on all sides of the generator? Please, if someone could guide me on this matter. Thank you very much.
 
I would check with the generator manufacturer. As you've stated the 5' rules for outdoor installations would obviously not apply to a indoor generator room.
 
Don't skimp on service space! Nothing worse than having to take the doors off the hinges because you can't get around them when they're open!
Plus, with our 'growing' population, extra work space will be needed!
.
Do you have to allow space to pull out the old gen and move in a new one some time in the future?? No awkward corners to go around??
 
We had at least one 2' deep by 4' wide cabinet in every indoor generator room. We would store the water filling container, 5 gallon container of RO water, clean rags, hydrometer, funnel for adding oil, gallon bottles of oil & coolant etc. Also on gen set rooms with large ( 2,000 KW gen sets ) we locked up a 10' stepladder to check and add coolant. Had signs on every gen set rooms doors saying " No storage allowed ". When contractors left wood or Sheetrock in generator rooms we would place them.outdide in the rain to help them learn how to read signs. Safety department for some reason did not allow us to store one box of 4 or 8' fluorescent in any generator rooms but in rooms with 3 big 2,000 KW generators we were allowed to store a couple of 55 gallon drums of generator oil . Nice to have at least 3' clearance on smaller gen sets and 5' on ones 750 KW.
 
garbo said:
...Safety department for some reason did not allow us to store one box of 4 or 8' fluorescent in any generator rooms but in rooms with 3 big 2,000 KW generators we were allowed to store a couple of 55 gallon drums of generator oil . Nice to have at least 3' clearance on smaller gen sets and 5' on ones 750 KW.
Click to expand...
The problem was more likely the -box-, not the fluorescent tubes! Would the box of bulbs have been OK if it was in a metal storage cabinet?
 
garbo said:
We had at least one 2' deep by 4' wide cabinet in every indoor generator room. We would store the water filling container, 5 gallon container of RO water, clean rags, hydrometer, funnel for adding oil, gallon bottles of oil & coolant etc. Also on gen set rooms with large ( 2,000 KW gen sets ) we locked up a 10' stepladder to check and add coolant. Had signs on every gen set rooms doors saying " No storage allowed ". When contractors left wood or Sheetrock in generator rooms we would place them.outdide in the rain to help them learn how to read signs. Safety department for some reason did not allow us to store one box of 4 or 8' fluorescent in any generator rooms but in rooms with 3 big 2,000 KW generators we were allowed to store a couple of 55 gallon drums of generator oil . Nice to have at least 3' clearance on smaller gen sets and 5' on ones 750 KW.
Click to expand...
Good words of advice on storage. We electricians keep areas around electrical equipment clear for others to put stuff in.
I had a safety manager store blankets in front of an ATS, I had to manually operate the switch in the dark. I moved his stuff outside the room
 
The generator manufacturer should be able to give you the clearances you need for maintenance of the generator. But remember that you will still need the required clearances at the generator output breaker location.

Also, more than likely, you will have a day tank for fuel in the room as well.
And I believe the room itself will have a to a minimum of 2 hour wall construction, but that should be determined by the architect.
 
Before I was hired the middle of three 16 cylinder 2,000 KW generators had the what was told the crankcase shaft replaced. They were lucky that there was probably 12' clearance on both sides of generator because they had to lay the generator on its side to make the repairs.Was also lucky that the generator rooms had a high ceiling which years later they installed maybe 8' diameter round guess something like a catalytic converter to reduce stack emissions on both 3 natural gas & diesel gen sets.
 
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