Multiple Generators...again

Status
Not open for further replies.
K

keschaefer

Member
Location
Raleigh, NC
I had a comment come from an inspector that, under 225.30, a second generator may not be added to a building unless the existing generator is over 2000 A.

The facility has an existing generator (500kW) feeding Art. 700 and Art. 702 loads via separate ATSs. A second generator is being added to feed a UPS and associated HVAC loads (Art. 702) for a new data center area within the building. The building was originally designed for two generators and ATSs, only one was installed; this is an expansion project.

I read 225.30(A) as stating that "Additional feeders" may be added for any/all instance of the listed loads, with no limit.

The inspector is stating that since the first generator is less than 2000 A and is feeding one (or more) of the loads listed no additional feeders may be added.

Argument 2:
Article 225 II is for More Than One Building or Structure; there is only one building on this site fed by one utility transformer.

Thanks for your time.
 
If you read the first line of 225.30(A) it says additional feeders or branch circuits.
There are many buildings that have standy, by back-up to the stand by and back-up to the back-up and then redundant back-up to all those back-ups.
Rick
 
The inspector is saying a second generator may only be installed with generator paralleling gear, not two generators feeding separate ATSs. And the second generator would only be allowed if the generators were over 2000 A.
 
Sierrasparky said:
As always ask him for the code or city/county statute
Click to expand...

The inspector is quoting 255.30(A) as stating that only one feeder (in addition to the normal service) is allowed to feed the listed loads. He says that since the first generator feeds Emergency systems and Optional loads we cannot add the second generator to supply other optional loads.
 
Is it they don?t want 2 gensets out of rotation feeding the building at the same time unless the one is over 2000A?

If so I have seen it before.


A bakery has a 75 KW and a 150 KW gensets. The 75 KW auto starts at an outage to run there critical loads. If the 75 KW fails to start the 150 KW starts. If there in the middle of a production run or need to do a production run without utility power they start up 150 KW. The only time both gensets run at the same time is during worm up and cool down cycles.
 
keschaefer said:
The inspector is quoting 255.30(A) as stating that only one feeder (in addition to the normal service) is allowed to feed the listed loads. He says that since the first generator feeds Emergency systems and Optional loads we cannot add the second generator to supply other optional loads.
Click to expand...

225.30(A) clearly states additional feeders are allowed under 1-6. It sounds like he is quoting 230.2(C)1
 
225.30

225.30

I don't really understand why we're having this discussion since, as you stated multiple times, 225.30 clearly applies to sites with more than one building or structure. Seems like you have to make the inspector understand that he is wrong.
 
Status
Not open for further replies.
Top