NEC 2017 Article 517 for Nursing Home with Generator Switchboard Connection

[cyriousn]

I've recently inherited a One-Line at work and I'm trying to understand if the scenario below would meet 517.40. It feels like the selective coordination will be difficult and I'm not sure if I'm interpreting 700.10 (b) correctly.

(2) 350kW 480V generators connecting into the generator switchboard. Each generator shown with a breaker and paralleled through controls.

Generator Switchboard Section 1
(2) breakers for the 350kw generator connections
(1) breaker for temp generator / load bank connection.
(1) breaker for the Article 517 equipment
(1) breaker for optional standby controlled to load shed if needed.

Generator Switchboard Section 2
(1) breaker for the Article 517 life safety, treating like article 700 per 517.26
(1) breaker space for a future fire pump.

 

[mbrooke]

PM me the single line, but as I'm reading it here I don't see anything that stands out of place or not to code.

 

[ron]

I don't do much in Article 517, so with the assumption that there is something in 517 that allows you to combine the 3 ATS loads that I would normally expect to see associated with the Essential electrical system, then 700.10(B)(5)a requires separate vertical sections of the switchboard for emergency loads and non-emergency loads. It seems that Section 1&2 of your switchboard has them mixed. For Section 2, the fire pump is likely a 701 load, not 700 load.

 

[cyriousn]

I don't do much in Article 517, so with the assumption that there is something in 517 that allows you to combine the 3 ATS loads that I would normally expect to see associated with the Essential electrical system, then 700.10(B)(5)a requires separate vertical sections of the switchboard for emergency loads and non-emergency loads. It seems that Section 1&2 of your switchboard has them mixed. For Section 2, the fire pump is likely a 701 load, not 700 load.

I totally overlooked that the fire pump is not considered an emergency circuit. Something always makes me think of it as emergency and not legally required standby. At that point we would have the fire pump, equipment, optional standby all on section 1 and section 2 would be just for the life safety / emergency.

 

[mbrooke]

Is there any difference between section 1 and section 2?

 

[cyriousn]

Is there any difference between section 1 and section 2?

No difference really, both have fully rated buss. The switchboard will be supplied by the generator vendor in order to get the paralleling of the two gen sets together. The life safety just has to be in a separate vertical section for Article 700 requirements. Now I'm working through if I can find a dual purpose docking station for the temp gen and load bank hookups. Otherwise I may need to use two single purpose docking stations, 1 for the load bank and 1 for the temp generator hookup.

 

[cyriousn]

I don't do much in Article 517, so with the assumption that there is something in 517 that allows you to combine the 3 ATS loads that I would normally expect to see associated with the Essential electrical system, then 700.10(B)(5)a requires separate vertical sections of the switchboard for emergency loads and non-emergency loads. It seems that Section 1&2 of your switchboard has them mixed. For Section 2, the fire pump is likely a 701 load, not 700 load.

After doing some more digging, the fire pump appears to be 700 load. The informational note at the end of 700.2 mentions fire pumps. The breaker for this load will be in the future so either switchgear section will have a space for the breaker if the AHJ disagrees with the design.

 

[mbrooke]

No difference really, both have fully rated buss. The switchboard will be supplied by the generator vendor in order to get the paralleling of the two gen sets together. The life safety just has to be in a separate vertical section for Article 700 requirements. Now I'm working through if I can find a dual purpose docking station for the temp gen and load bank hookups. Otherwise I may need to use two single purpose docking stations, 1 for the load bank and 1 for the temp generator hookup.

Honestly, I see no issue from where they originate.