Breaker trip adjustment?

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Mr. Serious

Mr. Serious

Senior Member
Location
Oklahoma, USA
Occupation
Electrical Contractor
We have a commercial job with three subpanels. The MDP was originally supposed to have 400A, 225A, and 100A feeder breakers for the subpanels. But a change was made very early in the process, the 400A subpanel was changed to 225A.

So, they sent me a submittal with all the information, and I neglected to check it in time. When I finally looked at the submittals 5 months later, I saw they had changed the subpanel, but had not changed the feeder breaker. I immediately contacted them and asked if the 400A breaker could be changed to a 225A one, and they thought it could, but they never got back to me and now it's been two more months, and the customer will be ready to install this stuff soon. I'm trying to deal with this and I see the two breakers have two different frame sizes, so maybe we couldn't change the 400A breaker to a 225.

1 Lighting Panelboard, ReliaGear RQ
Marks: MDP

1 Section(s), NEMA 3R Cabinets
600 Amps, 3 Phase 4 Wire 208Y/120V, 50/60 Hz
Minimum Interrupt Rating: 22kA Fully Rated
Incoming Feed: Bottom
Surface Mounted
12 Circuits
UL67 / CSA C22.2 No. 29 Certified
cULus Certified
Height: 76.5 Inches; Width: 20 Inches; Depth: 6.21 Inches
1 600 Amps Main Lugs
1-lug/phase 2-cable/lug 2/0 -500 kcmil

Main Option Details
1 Copper Bus Heat Rated
2 Ground-Box bonded TGL2
1 Ground main lug TGL20
1 100% Rated Neutral
1 NEMA 3R Cabinets

Feeders
1 Breaker Device 400 Amps 3 Poles XT5N400
1 TMA
1 Breaker Device 225 Amps 3 Poles A2N250
1 Breaker Device 100 Amps 3 Poles THHQB
1 Breaker Device 20 Amps 1 Poles THHQB

Modifications
1 Nameplates
1 Interior: AQF3126MBX AXQ3G1B7
1 Box: AB763
1 Front : NONE

I see they have adjustable trip points, but I'm not sure if it can be set down that low. Can the above-listed 400A breaker be adjusted to 225A? If the 400A breaker can be adjusted to 225A, what is the procedure to make sure the adjustment complies with code? I found this thread saying something about a seal on the breaker: https://forums.mikeholt.com/threads...400-amp-feeder-to-distribution-panel.2566662/ I'm just not sure what that is, never having worked with these very extensively.
 
Jraef said:
That breaker does have an LSI electronic trip, and is programmable, but the lowest setting on a 400A breaker is 280A.
Click to expand...

Thank you. I had seen the page you linked, but I missed the line that says: Setting Range: 280…400 A

The subpanels are MLO, except for the 100A one which is the kitchen subpanel, and they told me they provided it with a shunt trip 100A main breaker (instead of using a 100A shunt trip feeder breaker as the prints show).

The feeder and panel on the prints is 400A, but I've already been over this and have received assurance from the architect and the owner that the change to 225A is what they want, to save cost. The architect says we can go with whatever the owner wants on this, and the owner wants to change to a 225A feeder and panel. There is almost no load on this panel currently, it was mainly for future expansion, and the owner changed his mind about the amps required. I only neglected to make sure the change was implemented properly in the beginning, by neglecting to look at the submittals that the supply house sent me.

I don't know if they make a 225A breaker that fits in the spot where the 400A breaker is. The supply house "gear specialist" says he has a 225A breaker for me so that I can change it out, but it was his understanding that it fits in the same spot as the 400A breaker, so I would be able to return the 400A one after changing it. But from what I'm seeing, they're different sizes, and it is very unclear to me if the MDP even has provisions for a second 225A breaker to be mounted. I think he told me they have everything except the MDP in stock now, so I can't even go look at it to verify.
 
infinity said:
Do they make a 400 amp frame-225 amp trip breaker?
Click to expand...
Well, I didn't see one on my cursory examination of ABB's web site.

I just looked at my bill from the supplier. I've been billed for the 75% of the panels package that they have in stock now. And they list the MDP interior as one of the items they have in stock. So, I guess I can go look at that, and look at the extra breaker they have, and see if there is a way to make it work.
 
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