Attribute Schema Library
Attribute schemaelectrical distribution

Panelboards & Load Centers Attributes

Panelboards and load centers sit between a service or feeder and the branch circuits it feeds: a bus, a main breaker or main lugs, breaker spaces, and an enclosure. Both are built to UL 67 and NEMA PB 1. "Load center" is the trade term for the residential and light-commercial end; "panelboard" covers the commercial NQ/NF, P1, and Pow-R-Line class.

Buyers are contractor purchasing desks, the distributor's quotation group working a 26 24 16 spec section, and MRO buyers replacing a panel in an existing opening.

The data is hard for structural reasons. Commercial panelboards ship as separate interiors, boxes, and fronts, three catalog numbers that only work together, so one "product" is a relationship rather than a row. Much of the spec is encoded in the catalog number itself: a suffix for feed-through lugs, a letter for copper versus aluminum bus, a digit for voltage class. And the ratings that decide the sale (SCCR by voltage, series-rated combinations, lug wire ranges) live in tables at the back of the manufacturer PDF, keyed to a device number that never reaches the catalog record.

Core

Every SKU needs these. Without them the record is not a product, it is a row.

Assembly Role
enum
Panelboard interior

Decides whether the SKU ships as a complete panel or as an interior that still needs a box and a front. Drives every downstream compatibility question.

Main Type
enum
Main lug only (MLO)

The first filter on every rail. MLO feeds from an upstream device; a main breaker is needed where the panel is service equipment or needs a local disconnect.

Main Device Amperage
number · A
200 A main breaker

The rating of the main breaker itself. Sized to the feeder and the available fault current, and often lower than the bus it sits on.

Bus Ampere Rating
number · A
225 A

What the bus can carry, and the number the panel schedule is built around. A 225 A bus with a 200 A main is not a 200 A panel.

System Voltage
enum · VAC
480Y/277 VAC

Determines the bus and breaker family. 208Y/120 and 480Y/277 panels are not interchangeable, and SCCR is quoted per voltage.

Phase & Wire Configuration
enum
3-phase, 4-wire

3-phase 4-wire carries a neutral for line-to-neutral loads; 3-wire does not. Wrong wire count means the panel cannot land the feeder as designed.

Pole Spaces
number
42 pole spaces

How many single-pole breaker positions the interior has. Drives box height and whether the panel schedule fits without a second enclosure.

Bus Material
enum
Tin-plated copper

Copper is specified on most commercial jobs and priced accordingly; aluminum is standard on load centers. Spec sections call this out explicitly.

Short Circuit Current Rating (SCCR)
number · kA
22 kA at 240 VAC

Must equal or exceed available fault current at the supply (NEC 110.10, marked per 408.6). Voltage-dependent, so the value needs its voltage.

Enclosure Type (NEMA)
enum
NEMA 3R

Sets where the panel can be installed. NEMA 1 is indoor only; 3R is rainproof; 4X handles washdown and corrosive areas.

Mounting / Cover Style
enum
Surface

Flush trim needs a finished wall opening; surface mounts to the face. Ordering the wrong front means the panel cannot be closed out.

Manufacturer Part Number
identifier
NQ442L2C

The catalog number is how the trade orders, cross-references, and quotes. It also encodes bus, mains, spaces, and voltage class.

Differentiating

What buyers actually compare on. This is where catalogs win or lose the filter.

Breaker Type Accepted
enum
QO

Bus stab geometry is proprietary. QO, Homeline, BR, CH, and QP are not interchangeable, and the attach breaker sale depends on this field.

Plug-On Neutral
boolean
Yes

Plug-on neutral panels take AFCI/GFCI breakers without a pigtail. Contractors filter on it to match the breakers they already stock.

Enclosure Dimensions (H x W x D)
text · in
44.00 x 20.00 x 5.75 in

Retrofit buyers are replacing a panel in an existing opening. Box height and width decide whether the swap needs drywall work.

Compliance & identifiers

Standards, regulatory data, and the identifiers channels reject you for missing.

Suitable for Use as Service Equipment
boolean
Yes

Service-entrance duty requires a main disconnect and a bonded neutral, evaluated to UL 869A. Without the field, the AHJ question goes unanswered.

Country of Origin
identifier
United States

Federally funded work carries BABA domestic-content preference, and the buyer needs origin before the bid, not at delivery.

GTIN / UPC
identifier
785901175599

Required to list on marketplaces and to sync through the industry data pool. Missing GTINs get items rejected at load.

The fields that aren't in the schema at all

What most panelboards & load centers catalogs are missing.

The table above is the schema most catalogs already have. These are the attributes that usually aren't in it — each one surfaced by a signal from the live market rather than by an audit of what's already there. This is what Anglera's Schema Foundry does on a real catalog, in this category.

Supplier signal
+ Compatible box and front (trim) catalog numbers

Manufacturer catalogs pair each interior catalog number with a specific box and front. Distributor records list the interior alone, with no field pointing at the two SKUs that complete it.

The order ships as a bare interior with no enclosure or cover. The job stalls and the return is freight-heavy sheet metal.

Supplier signal
+ Main and branch lug wire range (AWG/kcmil)

Wire range sits in a lug table at the back of the manufacturer PDF, keyed to a lug catalog number. No distributor filter rail exposes it, and no product record carries it.

Contractor pulls 350 kcmil to a panel whose lugs stop at 4/0 AWG. A lug kit gets expedited or the feeder is re-terminated on site.

Competitor signal
+ Bus ampere rating held separately from main device amperage

Competitor rails expose bus rating and mains rating as two facets. Most catalogs carry a single 'Amps' field, so a 225 A bus with a 200 A main indexes as '200 A'.

Panels drop out of filtered results they belong in, and a buyer sizing to a 225 A bus is shown 200 A panels that will not take the schedule.

Search signal
+ Feed-through / sub-feed lug provision

The provision is encoded as a catalog-number suffix rather than a field. Buyers searching 'feed-through lugs 225A' get zero results and call the counter instead.

The buyer cannot find the panel that avoids a second enclosure, so the RFQ goes to whoever can answer the question by phone.

Supplier signal
+ Series rating combination reference

Series ratings are published as tested upstream/downstream device pairs in a separate manual. Catalogs carry one kA number and no pointer to the combination table.

A fully-rated panel gets quoted where a series-rated combination would have won on price, or the required series label never gets specified.

How Schema Foundry finds these

Messy in, governed out.

The same value, spelled every way electrical distribution suppliers spell it. A filter only works once they agree.

Main Type
MLOMain LugsMain Lug OnlyMAIN LUGS ONLYLugs OnlyM/L
Main lug only (MLO)

MLO versus main breaker decides whether the assembly can be service equipment. Free-text spellings break the most-used filter on the rail.

Bus Material
CuCOPPERCopper BusTin Plated CuCU BUS - TIN PLATEDCopper (Tin-Plated)
Tin-plated copper

Bare and tin-plated copper are different offerings at different prices. Collapsing both to 'Copper' loses a spec written into 26 24 16.

Short Circuit Current Rating
10kAIC10,000 AIC10 KA10kA RMS SYM10K AIC @ 240V22kA/10kA
10 kA at 240 VAC

AIC belongs to the breaker, SCCR to the assembly, and both vary by voltage. A bare '10K' cannot be checked against a fault-current study.

Enclosure Type
NEMA 1Type 1NEMA-1 IndoorN1IndoorUL Type 1
NEMA Type 1

'Indoor' is not a rating. UL 50E Type 1 is, and a 3R panel is also usable indoors, so an 'Indoor' value hides stock from the filter.

What buyers ask

Every one of these should be answerable from the attributes above. If it isn't, that's a gap.

  • Is this the interior only, or does it come with the box and front?
  • What box and trim do I order with this interior?
  • Is 225 A the bus rating or the main breaker rating?
  • Can this be used as service equipment, or do I need the main breaker version?
  • Will QO breakers fit this, or does it take Homeline?
  • What's the SCCR at 480Y/277, not at 240?
  • Will 250 kcmil land in these main lugs, or do I need a lug kit?
  • Is it plug-on neutral so my AFCI breakers work without pigtails?

What channels require

The same SKU, different mandatory fields per destination.

IDEA Industry Data Warehouse (IDW)
UNSPSC code (mandatory in IDEA Connector)Manufacturer part numberGTIN / UPCElectrical Attribute Schema attributesSpec sheet documentProduct description
Distributor site filter rail (Rexel, Platt, WESCO)
Bus ampere ratingMain typePhase & wire configurationPole spacesBus materialEnclosure type (NEMA)
Amazon Business
GTIN / UPCBrand and manufacturer part numberMain device amperageSystem voltageEnclosure type (NEMA)Country of origin
Federal / BABA-funded project submittals
Country of originManufacturer part numberShort circuit current rating (SCCR)Suitable for use as service equipmentSystem voltage

Panelboards & Load Centers data, in practice

Should load centers and panelboards share one schema?

Yes, with one added field. Both are built to UL 67 and covered by NEMA PB 1, and both carry the same core ratings: main type, bus amperes, voltage, phase and wire, pole spaces, bus material, SCCR, enclosure type. What differs is packaging. Load centers ship as a complete assembly with box and cover included, generally 100-225 A single-phase, taking QO, Homeline, BR, CH, or QP breakers. Commercial panelboards ship as an interior, a box, and a front under three catalog numbers, and run to 600 A and beyond at 208Y/120 or 480Y/277. An Assembly Role field carries that difference without forking the schema.

Should SCCR and AIC be one field?

No. AIC is the interrupting capacity of an overcurrent device, tested to UL 489 for breakers, and NEC 110.9 requires it to meet or exceed the available fault current at that device's line terminals. SCCR is the rating of the whole assembly: NEC 110.10 applies it to the panel and 408.6 requires it to be marked. They are different numbers on the same SKU, and both vary by voltage, so a panel can be 65 kA at 240 VAC and lower at 480Y/277. Store SCCR with its voltage. A bare '10K' cannot be filtered, compared, or checked against a fault-current study.

Does 'number of spaces' mean the same thing as 'number of circuits'?

No, and conflating them creates returns. A space is a physical breaker position on the bus. Circuits counts what can be landed once tandem or twin breakers are used in the spaces that accept them, which is why load centers are titled things like '20-space, 40-circuit'. Not every space accepts a tandem, and the panel label states which do. Commercial panelboards are usually specified in pole spaces (30, 42, 54) because tandems are not used there. Carry both as numbers, and carry them as fields rather than inside the description.

How do you model interiors, boxes, and fronts?

As three sellable SKUs with an explicit relationship, not as one row with the box specs in free text. Each interior catalog number is valid with a defined set of box catalog numbers, and each box with a defined set of fronts, flush or surface. Box selection is driven by pole spaces and mains, so a 42-circuit interior and a 54-circuit interior take different boxes. That relationship already exists in the manufacturer's selection tables. Once it is a field, the site can offer the box and front as required companions at the point of sale, and the counter stops rebuilding it by hand.

More electrical distribution schemas

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