Attribute Schema Library
Attribute schemaelectronic components

Relays: Attributes & Specifications Reference

A relay switches a load circuit with an isolated control signal. The category covers PCB power relays, plug-in industrial "ice cube" relays, low-signal and telecom relays, automotive relays, reed relays, force-guided safety relays and solid state relays — families that share a name and almost no comparable specs.

The spec that decides the sale is a conditional. "16 A" means nothing without "@ 250 VAC, resistive". Datasheets carry load life as curves, DC derating as charts, and coil data as multi-column tables where one PDF page covers thirty MPNs and 24 VDC differs from 110 VDC by a suffix. Supplier feeds flatten all of it to one number.

Then the vocabulary. US suppliers write SPDT, European datasheets write CO or 1 changeover, the case marking says 1C. Coil voltage arrives as 24VDC, DC24V, 24 V=, or a bare 24. Contact form and coil voltage are the first two filters a buyer touches, and the two that shatter into a dozen facet values if nothing normalizes them.

Core

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

Relay Type
enum
Power relay (over 2 A)

Splits the parametric tree. Power, signal, automotive, reed, force-guided safety and SSR parts share a name and almost no comparable specs below this node.

Contact Form (Contact Arrangement)
enum
1 Form C (SPDT)

The first filter a buyer touches. 1 Form C and 2 Form A are not interchangeable, and Form, SPDT and changeover notation must resolve to one value.

Coil Voltage (Nominal)
number · V (AC or DC)
24 VDC

The part is chosen by the control rail. Same relay body, different coil, different MPN suffix — and 24 VAC is not 24 VDC.

Coil Type
enum
Non-latching

Latching relays hold state without coil power and need a pulse driver; non-latching parts drop out on power loss. Fail-safe logic depends on which.

Contact Rating (Current)
number · A
16 A at 250 VAC, resistive

Headline switching capacity, and only meaningful carried together with the voltage and load type it was measured at.

Max Switching Voltage
number · VAC / VDC
250 VAC / 30 VDC

AC and DC limits differ by an order of magnitude on the same contact. Buyers filter both, and a single number hides the DC ceiling.

Mounting Type
enum
Through hole (PCB)

Through-hole, SMD, panel and DIN-rail socket plug-in are separate purchases. Decides whether the part lands on a board or in a panel.

Manufacturer Part Number (MPN)
identifier
RTE24024

The only reliable key across supplier feeds, aggregator search, PCN notices and the customer's BOM line. Coil voltage usually lives in the suffix.

Differentiating

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

Termination Style
enum
Quick connect, 0.250 in (6.3 mm)

PC pin, quick connect, screw and blade terminals decide the harness. Wrong termination is an immediate return, not a design debate.

Contact Material
enum
AgSnO2 (silver tin oxide)

AgSnO2 resists welding on inrush loads, AgNi is cheaper, and Au-clad AgNi is mandatory for dry-circuit or low-level signal switching.

Coil Power (Nominal)
number · mW (DC) / VA (AC)
400 mW

Sizes the driver and the thermal budget. A bank of 900 mW coils overloads a PLC output card that 200 mW coils would not.

Must Operate / Must Release Voltage
range · % of nominal coil voltage
Operate = 75% max, release = 10% min

Pickup and dropout guarantees. Decides whether the relay works on a 24 V rail sagging to 19 V at the end of a long cable run.

Electrical Life at Rated Load
number · operations
100,000 ops at 16 A, 250 VAC, resistive

Distinct from mechanical life, and worthless without the load it was tested at. 100,000 ops resistive is not 100,000 ops inductive.

Operating Temperature Range
range · °C
-40 °C to +85 °C

Panel interiors run hot. -40 to +85 °C parts and 0 to +55 °C parts sit side by side in the same series under the same photo.

Compliance & identifiers

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

Contact Rating Code (Pilot Duty / TV / HP)
text
B300 pilot duty; TV-5; 1/3 HP at 120 VAC

UL 508A panel builders spec by code, not by amps. B300, TV-5 and horsepower ratings govern inductive, tungsten and motor loads.

Agency Approvals & File Number
text
UL 508 File E43149; CSA C22.2 No. 14; VDE per EN 61810-1

The listing plus file number is what gets the relay into a listed panel or onto a CE declaration. A logo without a file number is not evidence.

RoHS / REACH Status
enum
RoHS compliant; no SVHC above 0.1% w/w

RoHS compliance plus REACH SVHC declaration. AgCdO contact parts sit under an exemption, and some buyers filter them out on sight.

GTIN / UPC and Country of Origin
identifier
00840012345678; CN; HTS 8536.49.00

GTIN gates marketplace listing; ISO 3166 origin plus HTS drives duty and tariff exposure on every quote. Each pack quantity is its own GTIN.

The fields that aren't in the schema at all

What most relays 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.

Competitor signal
+ Seal Rating (IEC 61810-7 protection category)

Digi-Key exposes Seal Rating as a filter and manufacturers encode RT II / RT III in the part-number suffix. Most distributor catalogs have no such field, so buyers cannot filter for wash-tight.

A CM aqueous-washes a flux-proof RT II relay. Cleaner reaches the contact chamber, so the failure surfaces in the field rather than on the line.

Supplier signal
+ Must Operate / Must Release Voltage

Every coil table states pickup at a max % of nominal and dropout at a min %. Distributor records carry nominal coil voltage only; the guarantee does not survive the feed.

Relay chatters or fails to pull in on a sagging 24 V rail. The engineer cannot answer the question from your page, so the RFQ goes to a catalog that can.

Search signal
+ Contact Rating Code (pilot duty B300 / TV-5 / HP)

The codes are printed on the relay case and held in the UL file. Panel builders working to UL 508A ask for them by code; catalogs publish a resistive amp figure and stop.

Resistive amps sell a relay that cannot switch the tungsten or motor load. Panel fails inspection, relay is swapped after build, distributor eats the return.

Supplier signal
+ Coil Power / Coil Current at Nominal

Coil tables give resistance to a stated tolerance and nominal power for every voltage variant. Catalogs list coil voltage alone, so nobody can filter for a 200 mW low-power coil.

A buyer driving eight relays off one PLC output card cannot size the load, picks a 900 mW coil where 200 mW existed, and the card trips.

Supplier signal
+ Load Conditions Behind the Life Figure

Datasheets publish electrical life as a curve against load type and current, often only as a graph. Feeds flatten it to one operations number with no load stated.

An AC-rated relay goes onto a 30 VDC inductive load. Contacts weld far short of the published life and the claim lands as a warranty return.

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.

Contact Form (Contact Arrangement)
SPDT1 Form C1CCO1 changeoverSPDT (1 Form C)
1 Form C (SPDT)

US feeds send SPDT, European datasheets send CO or changeover, case markings say 1C. One arrangement, six values, a shattered facet.

Coil Voltage (Nominal)
24VDC24 V DCDC24V24 Vdc24 V=24
24 VDC

A bare '24' is unusable: 24 VAC and 24 VDC are different parts, different resistance, different MPN. '=' is the IEC symbol for DC.

Contact Material
AgSnO2Silver Tin OxideAg/SnO2AgSnO²AgSnO2 overlaySilver-tin-oxide
AgSnO2 (silver tin oxide)

Six spellings, one alloy. AgSnO2In2O3 is a different alloy, not a spelling variant — collapsing it destroys the buyer's inrush choice.

Termination Style
QC 2500.250" Quick Connect6.3mm fastonTab 6,3 x 0,8Faston 250QC 6.3
Quick connect, 0.250 in (6.3 mm)

Imperial and metric names for the same tab. Faston is a TE trademark used generically by suppliers, so it cannot be the governed value.

What buyers ask

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

  • Will a 24 VDC coil still pull in at 19 V at the end of a long cable run?
  • Is this relay wash-tight, or will an aqueous clean get into the contacts?
  • Does the 16 A rating hold on a DC inductive load, or only 250 VAC resistive?
  • What's the pilot duty rating? I need B300 for a UL 508A panel.
  • How much coil current each? I'm driving eight off one PLC output card.
  • Is there a gold-clad contact version for switching a 10 mA signal?
  • Does this drop into the same 11-pin socket as the relay I'm replacing?
  • Latching or non-latching — does it hold state if the panel loses power?

What channels require

The same SKU, different mandatory fields per destination.

Distributor parametric search (own site)
Relay TypeContact Form (Contact Arrangement)Coil Voltage (Nominal)Contact Rating (Current)Mounting TypeTermination Style
ECIAauthorized.com (authorized-distributor search)
Manufacturer Part Number (MPN)Manufacturer nameLifecycle statusRoHS / REACH StatusDatasheet URLStock and price breaks
Octopart / Nexar (design-engineer part search)
Manufacturer Part Number (MPN)Contact Form (Contact Arrangement)Coil Voltage (Nominal)Contact Rating (Current)Datasheet URLPackage / mounting
Amazon Business
GTIN / UPCBrandManufacturer Part Number (MPN)Country of OriginCoil Voltage (Nominal)Contact Rating (Current)

Relays data, in practice

Why isn't Contact Rating (Current) enough on its own?

Because it is a conditional. A relay rated 16 A at 250 VAC resistive may be rated 10 A at 30 VDC and far less on a DC inductive load — DC arcs have no zero crossing to extinguish at, so contact life falls off sharply as inductance rises. Datasheets carry this as a load-life curve or a derating chart, usually a graph rather than a table, which is exactly why feeds drop it. A record that publishes '16 A' and stops has sold a part the buyer will misapply. The field needs current, the voltage it was measured at, the load type (resistive, inductive, tungsten, motor), and the operation count the life figure refers to.

What is Seal Rating, and why does it belong on a relay record?

IEC 61810-7 defines protection categories for relay construction: RT 0 unenclosed, RT I dust protected, RT II flux proof, RT III wash tight, RT IV sealed, RT V manufacturer-specified. It matters at the contract manufacturer. An RT II flux-proof relay survives wave soldering but not an aqueous wash — cleaning solution reaches the contact chamber and the relay fails in the field rather than on the test bench. Manufacturers state the category on page one of the datasheet and encode it in the part-number suffix. Most distributor catalogs carry no such field, so the buyer who needs wash-tight cannot filter for it and calls someone else.

How should contact form be normalized?

To a single governed value carrying both notations, e.g. '1 Form C (SPDT)'. Suppliers send Form notation (1A, 1C, 2C), pole-and-throw notation (SPST-NO, SPDT, DPDT) and European changeover notation (CO, 1 changeover). These describe the same physical arrangement. Left alone, one facet fractures into a dozen values and the buyer's first click returns a fraction of the relevant inventory. The mapping is mechanical — Form A is normally open, Form B normally closed, Form C changeover — but it has to be applied to every incoming feed on every update, not once at load time.

Which relays need force-guided contact data on the record?

Any relay going into a safety-related control circuit. IEC 61810-3 (formerly EN 50205) governs relays with forcibly guided, mechanically linked contacts: the NO and NC contacts are tied to a common comb so they can never be closed simultaneously, even after a contact welds. That property is what makes the feedback contact diagnosable. The standard distinguishes Type A (all contacts mechanically linked) from Type B (linked and non-linked contacts in one relay), and that distinction changes the safety argument. If the record says only 'DPDT, 6 A', a machine-safety buyer cannot tell whether the part is usable at all.

More electronic components schemas

CapacitorsConnectorsResistorsSemiconductorsSensorsTerminal Blocks

Run this against your own relays.

Bring the category. We'll show you which of these attributes your catalog is missing — and the ones we find that aren't on this page yet.

Book a demo