Multiple power sources for Hospital

[pago cruiser]

Been a lurker for years as a Mechanical Designer/Facility Manager, and this site has been great for the occasional reference data.
Have a little more involved question.

Can a Hospital (with a Type 1 Electrical System), ALSO be fed power from another, completely independent Type 1 Electrical System?

At this facility (where I used to work as the Facility Manager), the Electrical Engineer (from an A/E) is recommending that a new ICU expansion/remodel be fed from a new Central Plant, with a new Electrical System. The Central Plant was originally to be powered from an attached and dedicated 480v system, which would remove appx 1200A (old chillers on the equipment branch) from the almost overloaded 208v system. My recommendation to the owner was to build the plant, take the load off the existing 208v system and use that extra capacity to power the ICU expansion. Yes, some switchgear work would be required as the Chillers are on the Equipment Branch, and we will need more capacity on the LS and Critical Branches as well; but the existing switchgear is only about 10 years old, so parts should not be a problem.

The Electrical Engineers plan will have the facility served by (2) isolated electrical systems, each Type 1.

To me, this seems problematic. I have spoken to the Electrical Engineer, and he insists there are no code problems with this.
While there may not be code issues, as the former Facility Manager this gives me cause for concern.

Outlets 20 feet away from each other - and within line of sight - will be on a different system.
Controls (with sensors and power supplies spread over a vast area) may have connections to both 208v systems.
In an emergency, shutting off power will be...more complicated.
I can envision construction workers running power cords to "available" outlets, with power tools connected to the different systems easily in contact.
The potential for cross connecting will ALWAYS be there; say, Contractor "A" extends a light on the new system, and then Contracator "B" extends a light from an adjacent area on the old system, and they are right next to each other. This does not seem a good idea.

So. Am I being chicken little here? Or is this truly a bad idea, notwithstanding "there is not a violation of NEC". If there is a NEC conflict, I would sincerely appreciate a pointer.

TIA

 

[infinity]

I have approved your post, please go to your profile and add your occupation for future reference.

 

[steve66]

See 517.18 and Exception #3.

 

[pago cruiser]

Thanks for the reply; but I do not see how it relates to the (2) different services? I have copied the section below:

"Exception No. 3: A general care (Category 2) patient bed location served from two separate transfer switches on the critical branch shall not be required to have circuits from the normal system."

Both the services are Type 1 Electrical Systems, and the Patient Beds in this expansion are ICU - considered Category 1 - Critical Care. I did neglect to state this earlier.
The same Exception you indicated is also valid for Category 1 systems - but it would seem that all it does is allow to NOT have a circuit from the normal system.

All that said, I did find this in the related Section 517.14:
"Where two or more panelboards serving the same individual patient care vicinity are served from separate transfer switches on the essential electrical system, the equipment grounding terminal buses of those panelboards shall be connected together with an insulated continuous copper conductor not smaller than 10 AWG".

This would indicate that the relevant panelboards - for EACH Type 1 system - would need to be tied together. These plants are about 1000 feet apart!

So I guess this could be done; but this still seems like a solution that will beget future problems...

And I thought of another potential issue laying in bed last night - the IT system servers and most hardware would be on system 1, while every other device (IP Switches, Routers, and all Network devices) in the facility (this place is about 150,000 SF) would be on the "other" system. Same deal with the VOIP phones. Cross connections on these type of devices will be impossible to avoid.

These Type 1 systems will also each have their own independent Generator backups. So when the grid goes down (which happen regularly, as the facility is rather remote), the cross connections will extend to emergency power.

 

[zbang]

You're "in luck" with the IT equipment in that most* inter-system interconnects will be twisted-pair ethernet which is by-design galvanically isolated at each end (using tiny transformers), Also, there may be fiber-optic connections in the network which also provide isolation; you could even specify that for the designers.

*referring to system-to-system, not between components of a given system (e.g. computer to display/projector); HDMI itself isn't galvanically isolated but there are boxes that will do it

 

[steve66]

All that said, I did find this in the related Section 517.14:
"Where two or more panelboards serving the same individual patient care vicinity are served from separate transfer switches on the essential electrical system, the equipment grounding terminal buses of those panelboards shall be connected together with an insulated continuous copper conductor not smaller than 10 AWG".

That applies to the branch circuit panels, which I assume would be much closer together.

These Type 1 systems will also each have their own independent Generator backups. So when the grid goes down (which happen regularly, as the facility is rather remote), the cross connections will extend to emergency power.

Not sure where you think there would be "cross connections".

 

[roger]

All that said, I did find this in the related Section 517.14:
"Where two or more panelboards serving the same individual patient care vicinity are served from separate transfer switches on the essential electrical system, the equipment grounding terminal buses of those panelboards shall be connected together with an insulated continuous copper conductor not smaller than 10 AWG".

This would indicate that the relevant panelboards - for EACH Type 1 system - would need to be tied together. These plants are about 1000 feet apart!

So I guess this could be done; but this still seems like a solution that will beget future problems...

The EGC's of the panelboards common to a patient care vicinity need to be tied together with a #10 bonding jumper, not the distribution plants. You should have a Normal Branch panelboard and a Critical Branch panelboard in each vicinity and the bonding jumper will keep the equipotential to below .1 ohms as required by NFPA chapter 6. The rooms will have to be commissioned by someone experience in testing Patient Care rooms.

Roger

 

[garbo]

Thanks for the reply; but I do not see how it relates to the (2) different services? I have copied the section below:

"Exception No. 3: A general care (Category 2) patient bed location served from two separate transfer switches on the critical branch shall not be required to have circuits from the normal system."

Both the services are Type 1 Electrical Systems, and the Patient Beds in this expansion are ICU - considered Category 1 - Critical Care. I did neglect to state this earlier.
The same Exception you indicated is also valid for Category 1 systems - but it would seem that all it does is allow to NOT have a circuit from the normal system.

All that said, I did find this in the related Section 517.14:
"Where two or more panelboards serving the same individual patient care vicinity are served from separate transfer switches on the essential electrical system, the equipment grounding terminal buses of those panelboards shall be connected together with an insulated continuous copper conductor not smaller than 10 AWG".

This would indicate that the relevant panelboards - for EACH Type 1 system - would need to be tied together. These plants are about 1000 feet apart!

So I guess this could be done; but this still seems like a solution that will beget future problems...

And I thought of another potential issue laying in bed last night - the IT system servers and most hardware would be on system 1, while every other device (IP Switches, Routers, and all Network devices) in the facility (this place is about 150,000 SF) would be on the "other" system. Same deal with the VOIP phones. Cross connections on these type of devices will be impossible to avoid.

These Type 1 systems will also each have their own independent Generator backups. So when the grid goes down (which happen regularly, as the facility is rather remote), the cross connections will extend to emergency power.

I retired from a large 550 bed Hospital and was very concerned about their electrical set up. Original building had four 760 KW generators on the 10 th floor and a new addition had three 2,000 KW generators in a basement probably 800 feet apart. I thought it would be best that being that each building had their own 13.2 KV dual services and 2 sets of generators were not tied into one another so thought all power should only be feed by the building that power came from. the old building and addition each had their own fire pumps. They did get a price for inter collecting both 480 volt generator locations but cost was way too high. I"m just an sparky and know nothing about what you called Type 1 systems. In my 10 years at this progressive hospital could never get an explanation of the different emergency power systems. only good thing that the controls on all of their generators would shed most non critical loads first in event of several generators going off line.