Mixing Regular Power With Emergency Power in Same Raceway

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jonny1982

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CA
Is it ok per code to have emergency power and regular power in the same raceway just within the electrical room? For instance, if there where several panels mounted on the wall and one of them being an emergency panel. Then there is a main section of regular gear and an emergency section of gear in the same electrical room. If one trough where to be run the perimeter of the eletrical room above every panel and the feeds for the regular panels fed out of the regular power swithgear where mixed with the feeds from the emergency panel fed out of the emergency section of gear, would that be acceptable per code?

Thanks
 

infinity

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New Jersey
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In general the two must be kept separate unless they're entering the same equipment like an ATS. Running a wireway around the room will likely get you in trouble with derating for more than 30 CCC's at any cross section of the wireway.
 

roger

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Is it ok per code to have emergency power and regular power in the same raceway just within the electrical room? For instance, if there where several panels mounted on the wall and one of them being an emergency panel. Then there is a main section of regular gear and an emergency section of gear in the same electrical room. If one trough where to be run the perimeter of the eletrical room above every panel and the feeds for the regular panels fed out of the regular power swithgear where mixed with the feeds from the emergency panel fed out of the emergency section of gear, would that be acceptable per code?

Thanks

As Infinity points out, there are specific allowances, see 700.10(B).

Roger
 

Russs57

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Location
Miami, Florida, USA
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Maintenance Engineer
Infinity, I’m in a hospital setting. So more like NFPA 110 and AHJ than anything NEC has to say.

Not a code guy so I might have the wrong reference.
 

roger

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Infinity, I’m in a hospital setting. So more like NFPA 110 and AHJ than anything NEC has to say.

Not a code guy so I might have the wrong reference.
For health care it is NFPA 70 article 517 part III and NFPA 99 chapter 6.

Roger
 

roger

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I should clarrify that NFPA 110 does prohibit the EPS and EPSS equipment from being in the same room as the normal power "service equipment".

Roger
 

JPinVA

Senior Member
Location
Virginia
Just because something "can" be done, does not mean a particular way of doing it is compliant. So if you determine it's "allowed", you need to also make sure the solution is also compliant in other ways. A few things I can think of off the top of my head are listed below. I'm not an electrician and don't have any practical experience in what is proposed...only enough knowledge to be aware of things that "might" be a concern and "might" need to be addressed by otherwise competent experts.

1. If both regular and emergency can be energized at the same time, ensure this scenario is evaluated when it comes to ratings.

2. Determine how each system is grounded and bonded and ensure any differences do not violate any restrictions or introduce problems.

3. Determine if the status of the backup (Separately Derived of Non-Separately Derived) causes any issues.

4. Be cognizant of inductive heating issues, and avoid or mitigate if necessary.
 

don_resqcapt19

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Illinois
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retired electrician
Remember that most of what people in the field call "emergency power" really is not. The only circuits that require separation from other circuits are Article 700 circuits.
 

Strathead

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Location
Ocala, Florida, USA
Occupation
Electrician/Estimator/Project Manager/Superintendent
Infinity, I’m in a hospital setting. So more like NFPA 110 and AHJ than anything NEC has to say.

Not a code guy so I might have the wrong reference.

That isn't true, Russ. Just for your information. There may be things in NFPA 110 that add more stringent requirements than the NEC which is NFPA 70, but all of the requirements of the NEC are fully applicable to health care facilities.
 

don_resqcapt19

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Illinois
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retired electrician
That isn't true, Russ. Just for your information. There may be things in NFPA 110 that add more stringent requirements than the NEC which is NFPA 70, but all of the requirements of the NEC are fully applicable to health care facilities.
There are modifications in 517 to rules found in the rest of the NEC and those modifications come from NFPA 99. NFPA 99 has the purview over the performance of hospital electrical systems, the NEC only has installation rules to support those performance rules.

One of those is that the time for selective coordination in 517 starts at 0.1 seconds, and for the rest of the code it starts at 0.0 seconds. The only part of the essential electrical system that is required to comply with Article 700 is the live safety branch.
 
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