Attribute Schema Library
Attribute schemaelectronic components

Terminal Block Attributes and Specifications

A terminal block clamps two or more conductors to a common contact inside an insulated body. They land in control panels, machine builds, switchgear, junction boxes, and onto PCBs. The buyer is a panel shop, an OEM machine builder, a maintenance storeroom, or a design engineer choosing a mating header — and each one arrives with a conductor size and a rail already fixed.

This category is dual-standard, and that is what breaks the data. The same part carries a UL rating and an IEC rating that are different numbers, because UL 1059 and IEC 60947-7-1 test it differently. Conductor range is published in mm² and in AWG independently, not converted. Suppliers write "5,08 mm", "0.200"" and "200 mil" for one pitch. Flatten any of those pairs into a single field and the record is wrong for half the people reading it.

The source shape makes it worse. One Phoenix Contact or Weidmüller PDF covers an entire family across every cross section, colour and level count, with torque, strip length and rail type in a connection-data block behind it. The per-SKU spec is a table cell, not a document.

Core

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

Manufacturer Part Number
identifier
3044102 (Phoenix Contact UT 4)

The only key the buyer, the supplier PDF, the UL file and the panel BOM all agree on. Everything else is derived from it.

Terminal Block Type
enum
Feed-through

Sets the whole function. Feed-through, ground, disconnect and fused blocks are not substitutes; they are separate line items on the same rail.

Mounting Style
enum
DIN rail, NS 35/7,5 and NS 35/15

Decides whether the part physically lands. A DIN-rail block and a PCB block are different products in the same category tree.

Termination Style
enum
Screw connection

Screw, push-in and spring cage change wiring labour, tooling and whether ferrules are needed. First filter most panel shops touch.

Number of Positions
number
2

Pole count. Load-bearing for PCB and pluggable blocks, where 2 to 24 positions is the primary variant axis.

Number of Levels
number
1

Single, double or triple level. Determines terminals per millimetre of rail — the constraint when the enclosure is already sized.

Terminal Width (Pitch)
number · mm
6.2 mm

Rail budget for DIN blocks, mating geometry for PCB blocks. A 5.00 header will not take a 5.08 plug.

Conductor Range – mm²
range · mm²
0.14–6 mm² (solid and flexible)

What the clamp actually accepts, per the supplier's own published figure. The field European and IEC-spec buyers filter on.

Conductor Range – AWG
range · AWG
26–10 AWG

The same clamp, as North American buyers size it. Published separately by the supplier — do not derive it from the mm² figure.

Differentiating

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

Nominal Current – IEC
number · A
32 A (at 4 mm² nominal cross section)

Per IEC 60947-7-1: five blocks looped in series, 45 K rise permitted. The number an IEC-spec machine builder designs to.

Nominal Voltage – IEC
number · V
1000 V

The IEC 60947-7-1 rated voltage. Runs higher than the UL figure on the same part because clearance rules differ.

Nominal Current – UL
number · A
30 A

Per UL 1059: three blocks adjacent, 25 °C ambient, only 30 K rise permitted. The number a UL 508A inspector reads.

Nominal Voltage – UL
number · V
600 V

The UL/CSA rated voltage. On the UT 4 this is 600 V against 1000 V IEC — same block, same screw, different test.

Compliance & identifiers

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

UL 1059 Use Group
enum
B, C

Groups A–E. Says whether the block may be field-wired or is evaluated for factory wiring only. Nothing on the part tells you.

Flammability Rating (UL 94)
enum
V-0

Gates the block into rail, transit and many OEM enclosure specs. V-0 or the RFQ stops.

Agency Approvals
text
UL/cUL Recognized E60425; CSA 13631; CB DE1-50905

File numbers, not logos. The panel builder's submittal package needs the file, and marine buyers need DNV or Lloyd's by number.

GTIN / UPC
identifier
GTIN-13 on the box; GTIN-14 on the carton

Required to list on Amazon Business and to match across supplier feeds. Blocks sold loose, in boxes and in packs need distinct GTINs.

Country of Origin
enum
Germany

Drives duty, USMCA and Trade Agreements Act eligibility. The same MPN can ship from two plants with two origins.

The fields that aren't in the schema at all

What most terminal blocks 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.

Marketplace signal
+ Current and Voltage Rating, split by standard (UL vs IEC)

Two marketplace listings for the same MPN (Phoenix Contact 3044102) read "600V 30A" and "1000V 32A". Both are right: 30 A/600 V is the UL figure, 32 A/1000 V the IEC. One field can't hold both.

A UL 508A panel builder sizing off the IEC number over-rates the block. The inspector reads the UL figure. That panel gets rebuilt, not re-labelled.

Supplier signal
+ UL 1059 Use Group

On the UT 4 datasheet the UL Recognized table (file E60425) has two unlabelled columns headed "B" and "C" — the use groups. Extractors take the 30 A and 600 V under them and drop the header.

Group D blocks are factory-wiring only. Without the field a panel shop field-wires one and finds out at inspection, with the block already in the enclosure.

Supplier signal
+ Tightening Torque and Stripping Length

The UT 4 lists 0.6–0.8 Nm and a 9 mm strip length on page 5 of a 22-page PDF, under Connection data. It is on no distributor's filter rail and rarely on the product page.

Panel shop sets the driver from the PDF or from memory. Under-torqued screw clamps back out under thermal cycling; the callback is a field failure, not a return.

Search signal
+ Marine and type approvals (DNV, Lloyd's Register, ABS)

The UT 4 carries DNV, Lloyd's Register, GL and RS type approvals, each with its own certificate number. Shipyard and offshore buyers search those names; the catalog has no field to search.

A whole buyer segment — marine, offshore, rail — cannot self-serve. The approval exists and the part is in stock, but the RFQ goes to whoever put DNV in a filter.

Competitor signal
+ Accessory relations (end cover, bracket, cross-connector)

Phoenix's own page links end covers, end brackets and cross-connectors to the UT 4. Re-hosted distributor records carry the block alone, with no relation to the parts it needs to work.

Order ships without the 2.2 mm end cover that closes the rail. Assembly stops for a sub-$2 part, a second order, and a second freight charge.

How Schema Foundry finds these

Messy in, governed out.

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

Termination Style
Push-inPUSH INPush-in CAGE CLAMPScrewlessPush In Spring ConnectionPush-in spring-cage
Push-In Spring

WAGO says CAGE CLAMP, Weidmüller says PUSH IN, Phoenix says Push-in. One termination, three house styles, three filter buckets.

Conductor Range – mm²
0,14...1,5 mm²0.14-1.5mm20.14 – 1.5 sqmm0.14 to 1.5AWG 26...1626-16AWG
0.14–1.5 mm² (26–16 AWG)

German sheets use a comma decimal and an ellipsis for range. Loaded naively, "0,14" parses as 14 and the size facet fills with nonsense.

Mounting Style (rail type)
NS 35/7,5TS 35TH 35-7.5EN 50022DIN 35mmtop hat rail
TH 35-7.5 (EN 60715)

EN 50022 was superseded by EN 60715, and Phoenix ships its own NS designation. Same rail, six buckets, none of them stocked together.

Color
graygreyGYgreen-yellowyellow/greenGNYE
Gray | Green-Yellow

Colour is the ground-block filter: green-yellow means PE, blue means neutral. Six spellings and the PE facet returns a fraction of stock.

What buyers ask

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

  • Will 2.5 mm² stranded with a ferrule fit, or do I need the next size up?
  • Is that 32 A the UL number or the IEC number?
  • Can I field-wire this, or is it factory wiring only?
  • What torque do I set the driver to, and how much insulation do I strip?
  • Does it clip onto NS 35/7,5, or do I need the 15 mm deep rail?
  • Which end cover and which cross-connector go with this block?
  • Is there a green-yellow ground block in the same 6.2 mm width?
  • Is it DNV or Lloyd's approved? This panel is going on a vessel.

What channels require

The same SKU, different mandatory fields per destination.

Digi-Key / Mouser parametric feed
Manufacturer Part NumberNumber of PositionsTerminal Width (Pitch)Conductor Range – AWGNominal Current – ULNominal Voltage – UL
Amazon Business
GTIN / UPCBrandCountry of OriginTerminal Block TypeNominal Current – ULNominal Voltage – UL
ETIM / BMEcat (EU electrical wholesale)
ETIM class codeNominal cross section (mm²)Termination StyleNumber of LevelsNominal Current – IECNominal Voltage – IEC
Distributor parametric search
Terminal Block TypeMounting StyleTermination StyleConductor Range – mm² and AWGNominal Current – UL and IECUL 1059 Use Group

Terminal Blocks data, in practice

Why do the UL and IEC current ratings differ on the same terminal block?

The test methods differ. Under IEC 60947-7-1, five blocks are mounted on a rail and looped in series with conductors at the rated cross section, and a 45 K temperature rise is permitted. Under UL 1059, three blocks are mounted adjacent to one another at 25 °C ambient and only a 30 K rise is allowed. Same part, different fixture, different permitted rise, different number. The Phoenix Contact UT 4 shows 32 A / 1000 V under IEC and 30 A / 600 V under UL and CSA (file E60425). Both are correct. Carry one field and you have to choose which half of your buyers to be wrong for. Carry two, labelled by standard, and neither has to ask.

The same part shows 1000 V, 800 V and 600 V. Which is right?

All three. On the UT 4, 1000 V is the IEC 60947-7-1 rated voltage, 600 V is the UL and CSA figure, and the VDE/IECEE CB entry gives 800 V — but only over a 0.2–4 mm² conductor range, narrower than the block's full 0.14–6 mm². That last detail is the one catalogs lose. A rating is not a scalar; it is a number bound to a standard, and often to a conductor range as well. Stored as a single "Voltage" column, the record silently picks one and discards the binding. Store the figure, the standard it was tested to, and the range it applies over.

Should conductor range be one field or two?

Two, and neither derived from the other. Suppliers publish mm² and AWG independently against the clamp geometry, not by conversion — the UT 4 lists 0.14–6 mm² and 26–10 AWG as separate rows in the connection-data table, and 2.5 mm² sits between 14 and 12 AWG with no clean mapping. If you convert, your AWG figure will eventually disagree with the datasheet, and the datasheet is what the buyer has open in the other tab. Load both from the supplier's own published values, facet both, and a search for "2.5 mm2" and a search for "14 AWG" both land on the same stocked part.

Why does a single terminal block family generate so many SKUs?

A feed-through family multiplies across nominal cross section (0.14 mm² up past 35 mm²), termination (screw, push-in, spring cage), levels (1, 2, 3), function (feed-through, ground, disconnect, fused, sensor), colour (gray, blue, green-yellow, orange, red), and packaging (box, bulk, tape and reel). Then the accessory tree hangs off it: end covers, end brackets, cross-connectors at every jumper span, marker carriers, plug-in bridges. Most of those variants share one PDF, which covers the family as rows in a table. The spec for any single SKU is a cell, which is why coverage is good for the six facets on the front page and thin for everything behind it.

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