Brand: ABB

ABB TF42-20 Thermal Overload Relay 16.0-20.0 A

Name: ABB TF42-20 Overload Relay 16.0-20.0 A | Seven Star LLC
Brand: ABB
SKU: TF42-20

Description

TF42-20 for motors of 16 to 20 A

TF42-20 (1SAZ721201R1049) is the TF42 step for 16.0 to 20.0 A. At 0.145 kg it is slightly heavier than the lower steps, which are listed at 0.130 kg, and it has a larger power loss of 1.6 to 2.5 W per pole.

This is the first step of the group that uses a 63 A gG fuse as listed short-circuit protection, so the cable and the upstream protection should be reviewed when replacing a smaller relay.

Technical specifications

Parameter	Specification
Type designation / order code	TF42-20 / 1SAZ721201R1049
Setting range	16.0 to 20.0 A (current setting scale in amperes)
Device type	Three-pole bimetallic thermal overload relay, trip class 10, phase-loss sensitive
Resistance / power loss per pole	6.25 mohm / 1.6 W at the lower and 2.5 W at the upper setting value
Short-circuit protection (gG fuse)	63.0 A gG
Rated voltage / frequency	Ue 690 V AC (600 V DC); 50/60 Hz; Ui 690 V; Uimp 6 kV
Auxiliary contacts	1 N.C. (95-96) + 1 N.O. (97-98); N.C. 3 A at 230 V AC-15
Reset / functions	Automatic or manual reset selectable; STOP and TEST buttons; status indication; trip-free mechanism
Terminal capacity (main circuit)	1/2 x 0.75-4 mm2 (up to 20 A)
Mounting	Direct on AF09 to AF38 contactors; or on a 35 mm DIN rail with a single mounting kit
Ambient temperature	Operation -25 to +60 C, temperature compensated; storage -50 to +80 C
Weight / protection	0.145 kg / IP20
Approvals (as printed)	cULus (UL 508), CB, CCC, GOST-R, ABS, RINA, DNV, Lloyd’s Register, CE

Terminals and losses

Terminal data are split at 20 A in the data sheet: relays up to 20 A take 0.75 to 4 mm2, while the higher steps take larger conductors. The TF42-20 therefore falls in the smaller-terminal group.

Resistance per pole is 6.25 mohm. Considering heat in a crowded cabinet, the 2.5 W per pole at the upper setting adds up to a few watts per relay at full current.

Use with contactors

AF09 to AF38 contactors accept the relay. Check the contactor AC-3 rating against the motor current of 20 A or less before choosing it;.

Operating frequency is limited to 15 operations per hour, or 60 per hour with 40 percent duty ratio, if the breaking current is 6 times the setting current and the motor start time does not exceed 1 s.

Documents and quotation

The linked file is the ABB TF42 thermal overload relay data sheet 2CDC106023D0201. Seven Star LLC supplies the TF42-20 on request from Muscat as an independent supplier; availability and lead time are given in the quotation. More products of this kind are in the Contactors & Overload Relays category, and a related item is the ABB AF09-30-10-11 contactor.

The data sheet is a general one for all TF42 steps, so the values on this page are those of the exact type shown in its tables. Confirm before ordering: the motor nameplate full-load current (the relay is set to it), the contactor type it will be mounted on, the short-circuit protection ahead of it and whether manual or automatic reset is wanted.

Datasheets & Documents

Datasheet ABB TF42 thermal overload relay data sheet 2CDC106023D0201 Download

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About brand

ABB is the Swiss-Swedish engineering group for electrification and automation: low voltage drives, motors, circuit breakers and motor control, process instruments and analysers, control systems and robots. It was formed on 5 January 1988 by the merger of two older companies. ASEA was founded in Västerås, Sweden, in 1883 by Ludvig Fredholm to make electric lighting and generators. BBC Brown Boveri was founded in Baden near Zurich in 1891 by Charles E. L. Brown and Walter Boveri. ABB Ltd is incorporated in Switzerland, headquartered in Zurich and listed on the SIX Swiss Exchange and Nasdaq Stockholm.

ABB company profile

Formed	5 January 1988, by the merger of ASEA (Sweden) and BBC Brown Boveri (Switzerland), each holding 50%
ASEA	Founded 1883 in Västerås, Sweden, by Ludvig Fredholm; first products electric lighting and generators
Brown, Boveri & Cie	Founded 1891 in Baden, Switzerland, by Charles E. L. Brown and Walter Boveri
Headquarters	Zurich, Switzerland; ABB Ltd became the group holding company in 1999
Ownership	Public company listed on SIX Swiss Exchange and Nasdaq Stockholm
Brands in the group	Baldor (US motors, acquired 2011), B&R (machine automation, acquired 2017), K-TEK level instruments, Endura and Navigator analysers, SACE breakers
Product families	Low and medium voltage drives (ACS series), motors, SACE Tmax and Emax breakers, contactors and soft starters, flow, pressure, temperature and level instruments, liquid and gas analysers, Contrac actuators, AC500 PLCs, Ability System 800xA and S800 I/O, protection relays, robots

Milestones

1883: ASEA is founded in Västerås, Sweden.
1891: Brown, Boveri & Cie is founded in Baden, Switzerland.
1987–1988: The merger is announced on 10 August 1987; ABB Asea Brown Boveri starts operating on 5 January 1988.
1999: ABB Ltd, incorporated in Switzerland, becomes the single holding company of the group.
2011 and 2017: Baldor Electric and B&R join ABB.
2020: ABB sells its power grids business to Hitachi, focusing on electrification, motion, process and machine automation.

Choosing an ABB drive

ABB's ACS drive codes are easy to read once you know the pattern. In ACS580-01-046A-4, "ACS580" is the drive family, "01" means a wall-mounted single drive, "046A" is the rated output current (about 46 A) and "-4" means a 380–480 V supply. The family is chosen by application: ACS355 for compact machinery, ACS310 for simple pumps and fans, ACS580 as the general-purpose drive, ACQ580 for water and wastewater with pump functions such as pipe fill and dry-run protection, and ACS880 for heavy industrial duty with direct torque control. Size the drive on the motor's full-load current, not only its kW rating, and allow derating for the high ambient temperatures common in Gulf electrical rooms.

Where ABB products are used

In Oman and the GCC, ABB drives and motors run pumps, fans and compressors in water and wastewater plants, district cooling, oil and gas and industry. ABB flowmeters, level instruments and analysers are used in water utilities, power and desalination plants and refineries, and SACE breakers protect switchboards in buildings and plants.

ABB products we list

Family	Examples
AC drives	ACS580, ACS580-01-046A-4, ACQ580, ACS355, ACS310, ACS880-01, FEN-31 encoder module
Breakers, motor control and protection	SACE Tmax XT, XT3N 250, SACE Emax 2, AF09 contactor, PSR soft starter, REM615 relay
Flow measurement	ProcessMaster FEP300, AquaMaster4, CoriolisMaster FCB430, VortexMaster FSV430, SwirlMaster FSS430, OriMaster FPD500
Pressure, temperature and level	266DRH, 267CS multivariable, TTH300, K-TEK AT100, LMT200, MT5000 GWR, KM26 gauge
Analysers	Endura AZ20, AK100 hydrogen purity, Navigator AW641 silica, AW402 chlorine, AWT210
Control systems and actuators	AC500, AC500-S, S800 AI810, AC 800F SA 811F, Contrac RSD50, Contrac RHD4000

Ordering ABB products: what we need

Send the full type code from the nameplate (for example ACS580-01-046A-4 or 266DSH...) and, for spare parts, the ABB ID number (such as 3BSE008508R1 or 1SBL176001R3010). For drives, add the motor power and current and any option codes (+...). For instruments, send the complete order code, which sets range, materials and approvals. Baldor motors are listed on their own brand page.

Facts checked against ABB company filings and published histories of ASEA and Brown, Boveri & Cie, October 2026.