kwired
Electron manager
- Location
- NE Nebraska
Are you using their on line catalog? That isn't too difficult to use. If you want more details on a particular item they have direct links to individual product information pages.
Sizing a single disconnect for a 320A meter socket
- Thread starter Rex Hungerford
- Start date
- Status
Rex Hungerford
Member
- Location
- Seattle
- Occupation
- Electrician
That is the same unit.
QOM2E2200NRB
I have to have QO or better. I like Sq D. There are jurisdictions such as San Francisco that want the main to match the branch breakers. I do have custom panels I provide and they are based upon Eaton QB breakers so I have to find a Eaton options too. At the moment I have 4 projects that all need 400A services and all are using NQ panels on the interior.Rex Hungerford
Member
- Location
- Seattle
- Occupation
- Electrician
I use to work for Square D as a PM and Estimator. Their catalog is clunky. You have to be in it a lot to find your way around. They would tell us in the field office to use google if we had to search.
kwired
Electron manager
- Location
- NE Nebraska
Why? Many loadcenters, particularly the Square D ones, have factory installed mains with 22kA rating but your typical branch breaker is 10kA and is series rated to go with that main breaker. If incoming available current is 10kA or less it really doesn't matter either.
If you have fuses for main, often they might be well above the AIR of the branch breakers, and sometimes they might be selected for that reason.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I always had trouble with Sq. D online catalog. It may be the terminologies that they used that I am not used to.
kwired
Electron manager
- Location
- NE Nebraska
Guess I mostly use Square D from panels, disconnects, transformers, motor controls to selectors, pushbuttons, and many relays and timers and such as well. I am used to using their catalog from back when I had hard copy of it. Because of that I sometimes find other catalogs a little hard to follow if they are arranged in a different manner.
A lot of details are covered in the catalog, like physical dimensions, knockout locations, lug sizes. Only occasionally do I need to look further into other product publications to get some detail if product isn't otherwise in front of me.
Rex Hungerford
Member
- Location
- Seattle
- Occupation
- Electrician
Once you find what you want, their catalog does contain a lot of useful information. I use to use the hard copy too. It takes time to walk down the ILine and panelboard section to determine what configuration you really want. It is all there. Just takes a little time to digest. It eats away at your day. I have to go online now a day to know what is normally stocked. Supply chain has really messed with the market.
kwired
Electron manager
- Location
- NE Nebraska
I kind of expect that as there is a lot of potential configurations that can be made from some base components. I do run into things I didn't know I could ask for from time to time as well.
I have learned when submitting request to look over the proposed items list carefully before telling my supply house to order. Sometimes I will give them specific item list other times will give general description of what I want, then find they missed a detail and the end result might not be something useful for my application. Most recent was asking them to configure a meter center. I asked for main lugs supply termination an two meter (200 amp) branch units. After close look at materials list I see they had a 400 amp main breaker supply unit, haven't asked for new quote yet but I bet the main lug unit is significantly less cost.
Another time I wanted a NQ panelboard, 200 amp main breaker three phase with feed through lugs. Pretty simple order and have purchased same thing a few times before. Also had some branch breakers on the order. My sales guy asked later on if this was on a high leg delta, I said yes even though I didn't think that should really matter on what was selected. But apparently it did and this panel took forever (and this was before recent supply chain issues) to be delivered. When I ordered this same panel combination in past they always just sent me stock items and I had to field assemble it, but this order ended up triggering a factory assembled panel with the three buses and three phase feed through lugs, but only with A and C phase made available to connect to branch breakers. I did not have any three pole breakers on the order, but did already have existing three pole breakers I intended to install in the panel. Before this I didn't know you could specify such special arrangements in the branch layout. Stock items do alternate ABC, ABC... but you can order them in any configuration you want.
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
That is pretty sad, given that the majority of high-leg delta services include 3 phase loads. I can see the usefulness of that configuration to avoid accidental connection of a branch circuit to the high leg, but just the specification of high-leg delta should not be enough to specify that.
kwired
Electron manager
- Location
- NE Nebraska
His panel builder software configured it as all 30 spaces being "120 volt prepared spaces" since there were no three pole breakers included on the order from what I recall, my guess is there probably was a way around that but got missed in the process. One easy way probably would been to configure as 208/120 instead of high leg delta. If built from stock items it should still give you same result as what I wanted with 240 volt rating on the label. If factory assembled panel you might get it with label that designates 208/120
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
I mostly use Siemens panelboards and they have a different letter code for 120/240 three phase over 120/208. I can't think of what the actual difference would be other than labels. Not sure what they would do with 2 poles if I ordered them with the panel, if they would use their non slash rates ones (r after the part number i.e B220R) or just install them in the non higher leg phases..
kwired
Electron manager
- Location
- NE Nebraska
Not sure what my sales guy had for selections when he configured this panel, but guessing he missed something somewhere and that is how we ended up with what we got. I've ordered similar panels before and never had to distinguish between 208/120 and high leg delta, and almost always ended up getting in stock components that need to be field assembled to complete the setup. Usually this way because that results in quickest time to fulfill the order.
Can the 83% rule be used for paralleled Service Conductors? The NEC 2011 and 2020 when they brought the chart back does not seem to show that, only single sets
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Forget it I was thinking GE....
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I don't see why you can't.
400 amps is the highest the 83% is allowed. If you take 83% of 400 you get 332 amps. 2/0 copper parallel would be needed assuming no de-rating.
They brought the table back and it says nothing about parallel but the 83% is still there and that doesn't state that parallel conductors cannot be used.
kwired
Electron manager
- Location
- NE Nebraska
Take a look at 310.12 carefully in 2020, guessing 2023 remained similar but never checked it. 83% is still the base rules allowed for these dwelling services and feeders as long as they meet other stated conditions, but does mention you can use the table if there are no adjustment factors that would apply. Those tables yield same size conductor as if you calculated 83% and no adjustments, and is nothing more than a table for convenience. Parallel conductors that are all in same raceway will yield more than four current carrying conductors and would need adjustments for that reason anyway so in that case you would need to use the 83% calculation. If you paralleled in separate raceways and no other adjustments, 83% still results 2/0 copper or 4/0 aluminum for individual conductors.
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