NEC 517

[hhsting]

Please see attached sketch. I have multi occupancy commercial building and one of the tenants space is ambulatory space which has multiple operation rooms, multiple procedure rooms, operation prep rooms and post surgery operation rooms.

The building has 2000A main SWBD with 2000A main fused disco with GFPE that feed to internal 2000A SWBD ATS whose emergency side (E) has NO generator connected in place. The internal ATS load side feed 6 feeder breakers in 2000A SWBD each with GFPE which feed 6 different tenant spaces and one of the feeder breakers feed ambulatory space 800A switchboard.

The 800A switchboard has feeder breakers which feed essential system for the ambulatory tenant space which has life safety ATS, critical system ATS and Equipment ATS. Their is emergency generator switchboard with emergency generator which backup essential system.

Please see attached sketch.

Questions:

1. The 2000A SWBD main fused disco has GFPE, all the SWBD feeder breakers has GFPE per NEC 2014 517.17(B). However, the feeder breakers and GFPE are load side of internal ATS in SWBD 2000A which does not have generator connected on emergency side and ATS is not necessary to be in place but hard to remove. The SWBD ATS 2000A feeds 6 tenants and one of them is ambulatory space which has essential system. NEC 2014 section 517.17(B) last paragraph says additional levels of ground fault protection shall not be installed on the load side of essential system transfer switch. In order to comply I am confused is the ATS 2000A SWBD essential transfer switch and like to know your opinion should the SWBD 2000A ATS be removed?

2. Assume the ambulatory space is fed from line side i.e service connection line side of 2000A SWBD fuse disco which is NOT the attached sketch shows. However just assume for a moment. I like to know all of your opinions would NEC 2014 Section 517.44(C) be used to argue and enforce that service connection from line side of 2000A SWBD fuse disco to ambulatory space SWBD INSTEAD of 2000A SWBD 800A feeder breaker feed to ambulatory space SWBD Shown in Attached sketch would cause less disruption or NEC 2014 NEC section 517.44(C) about something else?

 

[hhsting]

Please see attached sketch. I have multi occupancy commercial building and one of the tenants space is ambulatory space which has multiple operation rooms, multiple procedure rooms, operation prep rooms and post surgery operation rooms.

The building has 2000A main SWBD with 2000A main fused disco with GFPE that feed to internal 2000A SWBD ATS whose emergency side (E) has NO generator connected in place. The internal ATS load side feed 6 feeder breakers in 2000A SWBD each with GFPE which feed 6 different tenant spaces and one of the feeder breakers feed ambulatory space 800A switchboard.

The 800A switchboard has feeder breakers which feed essential system for the ambulatory tenant space which has life safety ATS, critical system ATS and Equipment ATS. Their is emergency generator switchboard with emergency generator which backup essential system.

Please see attached sketch.

Questions:

1. The 2000A SWBD main fused disco has GFPE, all the SWBD feeder breakers has GFPE per NEC 2014 517.17(B). However, the feeder breakers and GFPE are load side of internal ATS in SWBD 2000A which does not have generator connected on emergency side and ATS is not necessary to be in place but hard to remove. The SWBD ATS 2000A feeds 6 tenants and one of them is ambulatory space which has essential system. NEC 2014 section 517.17(B) last paragraph says additional levels of ground fault protection shall not be installed on the load side of essential system transfer switch. In order to comply I am confused is the ATS 2000A SWBD essential transfer switch and like to know your opinion should the SWBD 2000A ATS be removed?

2. Assume the ambulatory space is fed from line side i.e service connection line side of 2000A SWBD fuse disco which is NOT the attached sketch shows. However just assume for a moment. I like to know all of your opinions would NEC 2014 Section 517.44(C) be used to argue and enforce that service connection from line side of 2000A SWBD fuse disco to ambulatory space SWBD INSTEAD of 2000A SWBD 800A feeder breaker feed to ambulatory space SWBD Shown in Attached sketch would cause less disruption or NEC 2014 NEC section 517.44(C) about something else?

Bump please

 

[hhsting]

Bump

 

[hhsting]

Please see attached sketch. I have multi occupancy commercial building and one of the tenants space is ambulatory space which has multiple operation rooms, multiple procedure rooms, operation prep rooms and post surgery operation rooms.

The building has 2000A main SWBD with 2000A main fused disco with GFPE that feed to internal 2000A SWBD ATS whose emergency side (E) has NO generator connected in place. The internal ATS load side feed 6 feeder breakers in 2000A SWBD each with GFPE which feed 6 different tenant spaces and one of the feeder breakers feed ambulatory space 800A switchboard.

The 800A switchboard has feeder breakers which feed essential system for the ambulatory tenant space which has life safety ATS, critical system ATS and Equipment ATS. Their is emergency generator switchboard with emergency generator which backup essential system.

Please see attached sketch.

Questions:

1. The 2000A SWBD main fused disco has GFPE, all the SWBD feeder breakers has GFPE per NEC 2014 517.17(B). However, the feeder breakers and GFPE are load side of internal ATS in SWBD 2000A which does not have generator connected on emergency side and ATS is not necessary to be in place but hard to remove. The SWBD ATS 2000A feeds 6 tenants and one of them is ambulatory space which has essential system. NEC 2014 section 517.17(B) last paragraph says additional levels of ground fault protection shall not be installed on the load side of essential system transfer switch. In order to comply I am confused is the ATS 2000A SWBD essential transfer switch and like to know your opinion should the SWBD 2000A ATS be removed?

2. Assume the ambulatory space is fed from line side i.e service connection line side of 2000A SWBD fuse disco which is NOT the attached sketch shows. However just assume for a moment. I like to know all of your opinions would NEC 2014 Section 517.44(C) be used to argue and enforce that service connection from line side of 2000A SWBD fuse disco to ambulatory space SWBD INSTEAD of 2000A SWBD 800A feeder breaker feed to ambulatory space SWBD Shown in Attached sketch would cause less disruption or NEC 2014 NEC section 517.44(C) about something else?

I apologize for my ignorance but I am really stuck on this one. I searched on my own in code but not able to find definite sections. Sorry for my ignorance. I guess this might probably end like other thread no one willing to help or answer further. Where is my buddy Electrofelon?

 

[d0nut]

1. The 2000A SWBD main fused disco has GFPE, all the SWBD feeder breakers has GFPE per NEC 2014 517.17(B). However, the feeder breakers and GFPE are load side of internal ATS in SWBD 2000A which does not have generator connected on emergency side and ATS is not necessary to be in place but hard to remove. The SWBD ATS 2000A feeds 6 tenants and one of them is ambulatory space which has essential system. NEC 2014 section 517.17(B) last paragraph says additional levels of ground fault protection shall not be installed on the load side of essential system transfer switch. In order to comply I am confused is the ATS 2000A SWBD essential transfer switch and like to know your opinion should the SWBD 2000A ATS be removed?

The ATS internal to the switchboard is not part of the essential electrical system, so the 517.17(B) prohibition against GFPE downstream would not apply. Even if there was a generator connected, I would expect this ATS to be classified as an optional standby generator so nothing in 517 would apply to the ATS. If the system is a 480V system, a second level of GFPE is required downstream of the 2000A main. The 800A feeder indicated in your sketch with GFPE would comply. If the system is 280Y120V or something similar, no GFPE would be required. You would not have to remove the ATS to comply with the requirements, but 2000A fused switch with GFPE and an internal ATS that isn't used screams obsolete equipment to me. Replacing that equipment would simplify the distribution system, but again does not seem like it is required.

2. Assume the ambulatory space is fed from line side i.e service connection line side of 2000A SWBD fuse disco which is NOT the attached sketch shows. However just assume for a moment. I like to know all of your opinions would NEC 2014 Section 517.44(C) be used to argue and enforce that service connection from line side of 2000A SWBD fuse disco to ambulatory space SWBD INSTEAD of 2000A SWBD 800A feeder breaker feed to ambulatory space SWBD Shown in Attached sketch would cause less disruption or NEC 2014 NEC section 517.44(C) about something else?

I am not sure I entirely follow what you are asking, but the 517.44(C) requirements don't really require anything specifically. It is requiring that you consider where you are putting the equipment to make sure it will stay functional if a natural disaster or some other disruption occurs. For example, if you are in a flood prone area, you may want to put the generator somewhere above grade to minimize the risk of it being unusable due to the flood water. You also need to make sure you have located the support systems in a safe area as well. A generator on the roof does no good if the fuel transfer pumps are at ground level and unusable because they are under 5 feet of water.

In your system, yes there are multiple overcurrent devices on the normal side of the essential electrical system transfer switches. Yes, moving the feeder up in the distribution system could mitigate some of the risk of one operating, but you also have the generator to mitigate the risk. If you lose normal power for whatever reason, the essential loads for the facility either continue functioning or provide save cessation of any procedures should still be powered.

 

[hhsting]

The ATS internal to the switchboard is not part of the essential electrical system, so the 517.17(B) prohibition against GFPE downstream would not apply. Even if there was a generator connected, I would expect this ATS to be classified as an optional standby generator so nothing in 517 would apply to the ATS. If the system is a 480V system, a second level of GFPE is required downstream of the 2000A main. The 800A feeder indicated in your sketch with GFPE would comply. If the system is 280Y120V or something similar, no GFPE would be required. You would not have to remove the ATS to comply with the requirements, but 2000A fused switch with GFPE and an internal ATS that isn't used screams obsolete equipment to me. Replacing that equipment would simplify the distribution system, but again does not seem like it is required.



I am not sure I entirely follow what you are asking, but the 517.44(C) requirements don't really require anything specifically. It is requiring that you consider where you are putting the equipment to make sure it will stay functional if a natural disaster or some other disruption occurs. For example, if you are in a flood prone area, you may want to put the generator somewhere above grade to minimize the risk of it being unusable due to the flood water. You also need to make sure you have located the support systems in a safe area as well. A generator on the roof does no good if the fuel transfer pumps are at ground level and unusable because they are under 5 feet of water.

In your system, yes there are multiple overcurrent devices on the normal side of the essential electrical system transfer switches. Yes, moving the feeder up in the distribution system could mitigate some of the risk of one operating, but you also have the generator to mitigate the risk. If you lose normal power for whatever reason, the essential loads for the facility either continue functioning or provide save cessation of any procedures should still be powered.

Thank you so much for replying. People here truly knowledgeable and experts.