400 Amp Service Questions

[wtrski]

Our facility is building a new Summer staff building which the engineer spec'd out a 600 Amp 3phase service. my load calculations came up with the ability to use a 400 Amp peak 320 amp 3 phase continuous service for this location from our electrical provider. Now the engineer shows that i am to come off this meter base to a 400 amp Main panelboard in our utility room which will feed over to 2 -200 amp sub panelboards. 1 panelboard in each wing of the building (guys side & girls side). I am also supposed to come off this meter with a 100 amp service to the Fire pump enclosure buried outside in a pit containing a 15 hp Fire Pump and a small jockey pump along with some controls.
My questions for you are as follows
1. do i need a breaker type disconnect at the meter base before running to both the 400 amp main panel and also the 100 amp fire pump enclosure?
2. The engineer showed that i am to use MLO Panels for the sub panels. Am i not required to have a main breaker in these sub panel's. it will be breakered at the main panel but my inspector has argued in the past that if the main disconnecting means is not in sight of the sub panel then a means of disconnect must be installed hence neeeding a panel with main breaker.
3. how should i go about feeding these two seperate services from the Meter base. should i bring the service from the meter base into a CT cabinet to use as a splice point to feed each service (main panel & Fire Pump enclosure) or should i just come off the Meterbase with each service.
4. is running 2- 4/0 THHN per phase & Neutral in 2-3" conduits adequate for this installation? Is a #2 GEC to 2 ground rods 6 feet apart bonded together appropriate.

 

[kwired]

Our facility is building a new Summer staff building which the engineer spec'd out a 600 Amp 3phase service. my load calculations came up with the ability to use a 400 Amp peak 320 amp 3 phase continuous service for this location from our electrical provider. Now the engineer shows that i am to come off this meter base to a 400 amp Main panelboard in our utility room which will feed over to 2 -200 amp sub panelboards. 1 panelboard in each wing of the building (guys side & girls side). I am also supposed to come off this meter with a 100 amp service to the Fire pump enclosure buried outside in a pit containing a 15 hp Fire Pump and a small jockey pump along with some controls.
My questions for you are as follows
1. do i need a breaker type disconnect at the meter base before running to both the 400 amp main panel and also the 100 amp fire pump enclosure?
2. The engineer showed that i am to use MLO Panels for the sub panels. Am i not required to have a main breaker in these sub panel's. it will be breakered at the main panel but my inspector has argued in the past that if the main disconnecting means is not in sight of the sub panel then a means of disconnect must be installed hence neeeding a panel with main breaker.
3. how should i go about feeding these two seperate services from the Meter base. should i bring the service from the meter base into a CT cabinet to use as a splice point to feed each service (main panel & Fire Pump enclosure) or should i just come off the Meterbase with each service.
4. is running 2- 4/0 THHN per phase & Neutral in 2-3" conduits adequate for this installation? Is a #2 GEC to 2 ground rods 6 feet apart bonded together appropriate.

1. I would say no, and maybe even say it could be a violation to put a disconnect at the meter location as you have suggested. 695.4(B)(3):

(3) Disconnecting Means. All disconnecting devices that are unique to the fire pump loads shall comply with items (a) through (e).
.
.
.(4)

Be located sufficiently remote from other building or other fire pump source disconnecting means such that inadvertent operation at the same time would be unlikely

2. If the feeder supplying the panel has overcurrent protection equal or less than the rating of the panel it does not need additional overcurrent protection. Separate buildings or structures need a main disconnecting means, and a main breaker in the panel is often the easy way to comply with this but is not the only way to do it. If the panel is in the same building or structure as the feeder overcurrent device no main is necessary at the panel.

3. I assume when you say CT cabinet you are just talking about a cabinet in which to make splices - there will be no CT's if using a 320 base meter socket. Which way to go with this depends on other conditions - if there is room or ability to install necessary lugs in the meter base to accomodate all the necessary conductors you can connect them all in the meter base, if not some other enclosure may be necessary to make splices in.

4. size your (minimum required) service conductors that carry all the load (ahead of the meter) to art 220 calculated load. If you figured a 320 meter socket is going to be sufficient then the load must not be pushing 400 very hard. Size your service conductors that feed individual disconnects to those disconnects.
For grounding electrode conductors soley connected to a ground rod - 250.66(A) does not require a conductor larger than 6 AWG copper no matter what size the service conductors may be. A ground rod just typically is not able to take any more current than a 6 AWG copper can deliver to it is the reason why.

 

[wtrski]

1. I would say no, and maybe even say it could be a violation to put a disconnect at the meter location as you have suggested. 695.4(B)(3):

ok I am confused on this and is probably because i tend to read into things a little to much more than is good for me a:lol:
according to that section 695.4(B)(3)(a)
the disconencting means shall comply with all the following:
(1)be identified as suitable for use as service equipment
(2)Be lockable in the closed position
(3)not be located within equipment that feeds loads other than fire pump
(4) be sufficiently remote from other building or other fire pump source disconnecting means such that in advertant operation at the same time would be unlikely

so according to that i do have to have a disconnecting means between the power source (meter Base) and the fire pump controller. it should be a seperate disconnecting or over current device from the main building supply (ok I had figured that), and lockable (no big deal), and according to item 4 i cannot locate that next to the disconnect feeding the service to the main panel but rather have the disconnecting means located remotely from it. so would that mean it should be located say in the pit with the controller an pump?


also 695.4(B)(1) states that (a) a single disconnecting means and associated overcurrent protective device(s) shall be permitted to be installed between the Fire pump power source(s) and one of the following
(1)a listed fire pump controler.
(2)a listed fire pump power transfer switch
(3)a listed combination fire pump controller and power transfer switch

now this section makes me think that it is optional to have a disconnecting or overcurrent protection means

so if i read this right i can have the meter base feed the service from a seperate set of lugs from the main building service feed within the meter base going to the Fire pump Controller pit where i have a 100 amp breaker type disconnect feeding the fire pump controller and jockey pump controller. I then also have a seperate feed from the Meter base going to a 400 amp disconnect next to the meter base feeding the main panel in the building. (i say next to the meter base as the distance between the meter base to the main panel is going to be approx 100 feet)

am i reading into the code again way to much or am i close to being right... lol

 

[kwired]

ok I am confused on this and is probably because i tend to read into things a little to much more than is good for me a:lol:
according to that section 695.4(B)(3)(a)
the disconencting means shall comply with all the following:
(1)be identified as suitable for use as service equipment
(2)Be lockable in the closed position
(3)not be located within equipment that feeds loads other than fire pump
(4) be sufficiently remote from other building or other fire pump source disconnecting means such that in advertant operation at the same time would be unlikely

so according to that i do have to have a disconnecting means between the power source (meter Base) and the fire pump controller. it should be a seperate disconnecting or over current device from the main building supply (ok I had figured that), and lockable (no big deal), and according to item 4 i cannot locate that next to the disconnect feeding the service to the main panel but rather have the disconnecting means located remotely from it. so would that mean it should be located say in the pit with the controller an pump?


also 695.4(B)(1) states that (a) a single disconnecting means and associated overcurrent protective device(s) shall be permitted to be installed between the Fire pump power source(s) and one of the following
(1)a listed fire pump controler.
(2)a listed fire pump power transfer switch
(3)a listed combination fire pump controller and power transfer switch

now this section makes me think that it is optional to have a disconnecting or overcurrent protection means

so if i read this right i can have the meter base feed the service from a seperate set of lugs from the main building service feed within the meter base going to the Fire pump Controller pit where i have a 100 amp breaker type disconnect feeding the fire pump controller and jockey pump controller. I then also have a seperate feed from the Meter base going to a 400 amp disconnect next to the meter base feeding the main panel in the building. (i say next to the meter base as the distance between the meter base to the main panel is going to be approx 100 feet)

am i reading into the code again way to much or am i close to being right... lol

I don't see the need for the 400 amp disconnect near the meter base, you should be able to run directly from meter to your service equipment at the supplied building, as well as directly from the meter to the fire pump equipment. Fire pump controller is likely rated for use as service equipment, jockey pump may need a service rated disconnect ahead of it but can be on the same supply that feeds the fire pump. Fire pump service equipment is not wanted near the regular service equipment so that it is not inadvertantly turned off when the rest of building power is turned off. This is about only place where this kind of thing is allowed other wise all service disconnecting means normally permitted are generally supposed to be grouped at the same location.