New 1200 Amp Service to feed 4 200A and 1 400A Panels .......

[mgookin]

Here in MA I am pretty sure an electrician can design any work they are doing.

I did a upgraded a 4,000 amp 208Y/120 service to a 3,000 amp 480Y/277 service and the entire plan was a sketch my PM had made.

In practice once things get too big insurance companies and contract requirements often force the use of PEs.

In MA an electrical contractor or electrician can design work that they will be installing.

Here is a link to the MGL Chapter 112 Section 81R
https://malegislature.gov/Laws/GeneralLaws/PartI/TitleXVI/Chapter112/Section81r

That's interesting.

 

[Cow]

Oregon is the same way if you have your supervisors license. We can design what we install. So, the majority of our work is designed by us, the project I'm on now has 6-8 400-2000 amp services, no prints, no engineers, just us coming up with a plan from scratch.

If you do it enough, it's just like anything else, you get used to it and don't think twice about having to do it.

 

[dionysius]

GFP or Not.....

GFP or Not.....

Beware your 1200 amp unit will need ground fault protection where the 400 amp did not.

I appreciate this being pointed out. Here is the analysis.
GFP will not be required since service has a total of 5 disconnects ( 4 x 200A and 1 x 400A ) which are each less than 1000A.
Thus since service has six disconnects or less (NEC 230.71) where each disconnect is less than 1,000 amps no GFP is required.

 

[electrofelon]

Oregon is the same way if you have your supervisors license. We can design what we install. So, the majority of our work is designed by us, the project I'm on now has 6-8 400-2000 amp services, no prints, no engineers, just us coming up with a plan from scratch.

If you do it enough, it's just like anything else, you get used to it and don't think twice about having to do it.

WA is the same. As a journeyman and electrical administrator (basically the same as a masters), I believe I could design a skyscaper if I wanted to and felt comfortable with it. Seattle has plan review for equipment over 400 amps, and the state has plan review for certain types of occupancies.

 

[electrofelon]

An Eaton Pow-R-Line C Switchboard (NEMA type 3R) with outgoing feeds will be specified to serve:

• One 400A feed going to existing MBP connected using existing 500 kcmil and conduit
• Four 200A feeds each to a new 200A panel using 4/0 Al

Out of curiosity, why are you going with a switch board? Do you need equipment with a metering section? Curious how that compares with the cost of a panel board, have you priced it? A 1200 amp I-line or Siemens P4 with 6 300 A breakers will cost about $5500-$6000.

 

[dionysius]

Switchboard vs Panelboard...

Switchboard vs Panelboard...

Out of curiosity, why are you going with a switch board? Do you need equipment with a metering section? Curious how that compares with the cost of a panel board, have you priced it? A 1200 amp I-line or Siemens P4 with 6 300 A breakers will cost about $5500-$6000.

This is a great question. If a Panelboard will accommodate metering then that would be the way to go. My requirements are to have EUCERC compliant metering since >800 Amps and 5 or 6 disconnects (breakers). I want to bolt it to an outside wall. The switchboard will cost circa $10,000.

 

[electrofelon]

This is a great question. If a Panelboard will accommodate metering then that would be the way to go. My requirements are to have EUCERC compliant metering since >800 Amps and 5 or 6 disconnects (breakers). I want to bolt it to an outside wall. The switchboard will cost circa $10,000.

I don't think anyone makes panel boards with integral metering compartments. You would need a stand alone CT cabinet. I don't know how much that would be but am guessing that you won't gain a whOle lot going with CT cab and panel board over the switchboard. Most utilities I work with, meter at the transformer so I don't have to worry about it.

 

[dionysius]

Alternate Design approach......

Alternate Design approach......

I don't think anyone makes panel boards with integral metering compartments. You would need a stand alone CT cabinet. I don't know how much that would be but am guessing that you won't gain a whOle lot going with CT cab and panel board over the switchboard. Most utilities I work with, meter at the transformer so I don't have to worry about it.

How about using 2 800A Panels such as Square D SB348IR in parallel. One has 400A and 200A breakers. The other has 3 200A breakers. Does this approach provide any advantage (redundancy is one!!) over a single panel approach??? Possibly more expensive though.

 

[electrofelon]

How about using 2 800A Panels such as Square D SB348IR in parallel. One has 400A and 200A breakers. The other has 3 200A breakers. Does this approach provide any advantage (redundancy is one!!) over a single panel approach??? Possibly more expensive though.

I dont think that would be cost effective. You would be paying for two metering sections, plus it would be a bit odd and the utility would likely not be thrilled with it. A single panel board and CT cab would likely put you a little ahead of that switch board, but you would have to weigh the increased labor and materials to connect them together.

 

[tkb]

I appreciate this being pointed out. Here is the analysis.
GFP will not be required since service has a total of 5 disconnects ( 4 x 200A and 1 x 400A ) which are each less than 1000A.
Thus since service has six disconnects or less (NEC 230.71) where each disconnect is less than 1,000 amps no GFP is required.

It would matter if it needs to be hot sequence or cold sequence.
If the POCO requires cold sequence a GFI main would be needed.

 

[dionysius]

So I am back to square one.......advice needed on grounding.......

So I am back to square one.......advice needed on grounding.......

Existing building has 400 Amp service with one MBP. This service is now being replaced with a new 1200 Amp service. All 3 phase 480/277V. Customer is very cost driven and wants to reuse the max amount.

An Eaton Pow-R-Line C Switchboard (NEMA type 3R) with outgoing feeds will be specified to serve:

• One 400A feed going to existing MBP connected using existing 500 kcmil and conduit
• Four 200A feeds each to a new 200A panel using 4/0 Al

After exploring some alternatives and with such great feedback and help from this forum I am back to the above and using a single 400A breaker (no parallel 200A!!); no GFP requirement; I will post available fault current when I get it.

What does the smart money say re grounding for this job?????? Conduits are all non-metallic so the ground wire can be run inside the conduits. What AWG would be code for this installation??? I normally tend to over specify but the runs here are a little long so cost is a driver once again. Also should the Neut and ground be connected at the switchboard only thus the 5 panels (1 x 400A and 4 x 200A) are treated as sub-panels????

 

[GoldDigger]

Yes the five panels will be subpanels with neutral isolated from ground. The MLO panel (switchboard) will be the service disconnect so the bond must be there or at the meter.

 

[kwired]

I dont think that would be cost effective. You would be paying for two metering sections, plus it would be a bit odd and the utility would likely not be thrilled with it. A single panel board and CT cab would likely put you a little ahead of that switch board, but you would have to weigh the increased labor and materials to connect them together.

The switchboard may need extra equipment to handle it where the panelboard and CT cabinet may be able to be handled by just a couple workers. Switchboards are sometimes set in place then the room/building is constructed around them - for existing applications it may not fit through existing doors and/or may be more difficult to navigate through the building to get to where it is to be placed compared to the panelboard.

 

[electrofelon]

It would matter if it needs to be hot sequence or cold sequence.
If the POCO requires cold sequence a GFI main would be needed.

That's true, however I have never heard of or seen cold sequence instrument metering of medium to large services

 

[dionysius]

Large Item Handling, Setting, Unboxing...........

Large Item Handling, Setting, Unboxing...........

The switchboard may need extra equipment to handle it where the panelboard and CT cabinet may be able to be handled by just a couple workers. Switchboards are sometimes set in place then the room/building is constructed around them - for existing applications it may not fit through existing doors and/or may be more difficult to navigate through the building to get to where it is to be placed compared to the panelboard.

Excellent point to consider. This Switchboard, however, is outside (NEMA 3R Flat Roof Enclosure) so there are no spatial placement issues as in a building. It ships as two separate cabinets and is joined by splicing the buses with supplied hardware. Dimensions and weight are as follows (WxDxH) in inches / Weight in lbs:

#1 36"x43"x90" 450lbs
#2 38"x43"x90" 660lbs
​

A forklift is available so this should be tractable with 3 lifter guys IMHO. Agree?? This is a bigger job than I have done so I am appreciative of any suggestions.

Any pointers to watch out for with the grounding/bonding????

 

[electrofelon]

Excellent point to consider. This Switchboard, however, is outside (NEMA 3R Flat Roof Enclosure) so there are no spatial placement issues as in a building. It ships as two separate cabinets and is joined by splicing the buses with supplied hardware. Dimensions and weight are as follows (WxDxH) in inches / Weight in lbs:

#1 36"x43"x90" 450lbs
#2 38"x43"x90" 660lbs
​

A forklift is available so this should be tractable with 3 lifter guys IMHO. Agree?? This is a bigger job than I have done so I am appreciative of any suggestions.

Any pointers to watch out for with the grounding/bonding????

The 1200 amp MLO panelboard I did recently was about 650 pounds iirc, but of course you get to break that down into three parts for install. The can wasnt real heavy, but the guts and the trim were a bear.

Regarding grounding, there is nothing much different. If not factory installed, there will be a main bonding jumper strap that is often a puzzle to figure out where it goes! Remember you will have to make that existing panel into a sub and move the GEC's over to the new MDP. Sometimes it works out nice to use the "GEC busbar method" (sorry dont have the code section handy) run your GEC from MDP to it, and then run all your GEC's to the bar; it covers your intersystem bonding terminal requirement too.