Upgrade 1200 Amps MSB

[David Christian]

I take on one Cinema project. The existing MSB is 800 Amps. It includes the load for Cinema itself and other tenant.

The existing MSB is in the electric room. Now as the client wants to add many new equipment in the project, we need to upgrade MSB from 800 Amps to 1200 Amps. It causes a problem that we could not use the existing electric room for new 1200 Amps MSB.

The client wants to upgrade to 1000 Amps. But based on our load calculation, it would not be enough. Therefore, how could I do to minimize client's cost and meet NEC code requirement.

By the way, this project uses PG&E transformer.120/208V 3 phase, 4W.

 

[mgookin]

If working space and egress are issues they need to be addressed. Just move some walls as part of the project.

 

[David Christian]

If working space and egress are issues they need to be addressed. Just move some walls as part of the project.

Thanks for your advice. I think I need to go to site to make sure whether it meets clearance requirement. The electric room is an old and narrow space.

 

[ron]

Depending on space available, rather than putting in a 1000A or 1200A to replace the 800A, consider adding a 2nd or 3rd main to the existing 800A. Sometimes you can squeeze a ~400A on an adjacent wall.

 

[electrofelon]

I take on one Cinema project. The existing MSB is 800 Amps. It includes the load for Cinema itself and other tenant.

The existing MSB is in the electric room. Now as the client wants to add many new equipment in the project, we need to upgrade MSB from 800 Amps to 1200 Amps. It causes a problem that we could not use the existing electric room for new 1200 Amps MSB.

The client wants to upgrade to 1000 Amps. But based on our load calculation, it would not be enough. Therefore, how could I do to minimize client's cost and meet NEC code requirement.

By the way, this project uses PG&E transformer.120/208V 3 phase, 4W.

A few thoughts: what kind of equipment are you considering? A 1200 amp panelboard really isn't that big - hardly bigger than a 800. Also how did you determine your loads? If you use 220.87 for the existing and add in the new loads, you will certainly get a "better deal" than a nec Calc for everything. Just an idea.

 

[Cow]

Depending on space available, rather than putting in a 1000A or 1200A to replace the 800A, consider adding a 2nd or 3rd main to the existing 800A. Sometimes you can squeeze a ~400A on an adjacent wall.

This was my thought as well, if a single 1200 or 1000 amp SWB wasn't practical.

 

[jim dungar]

A 1200 amp panelboard really isn't that big - hardly bigger than a 800.

But the working clearance/egress issue becomes a big problem.

 

[electrofelon]

But the working clearance/egress issue becomes a big problem.

Sure maybe if he is right on the edge as is and has a panelboard. In the case of siemens panelboards, and assuming he needs a main breaker, one would be looking at a P5 over a P4. The P5 is 2.75 inches more deep, and 6 inches wider. Of course very few details given: is existing panelboard or switchboard, does he need metering compartment, etc.....

 

[mgookin]

So put the new panel in another room or location, right?
Existing room is vested and new work must meet present day code?

 

[jim dungar]

Sure maybe if he is right on the edge as is and has a panelboard.

1200A likely requires two means of egress to, or twice the depth of, the working space where 800A does not.

 

[electrofelon]

1200A likely requires two means of egress to, or twice the depth of, the working space where 800A does not.

good point, I was not aware of that section. Although to nitpick, I am not sure I would use the word "likely". I would think a panelboard or a switchboard without a metering section (probably 1 section then) would be under 6 feet no?