Fluke 5440A Low Thermal EMF Test Lead Set

The Fluke 5440A Low Thermal EMF Test Lead Set is engineered for precision measurement applications where thermal electromotive force minimization is critical. This shielded, two-conductor cable assembly delivers sub-microvolt thermal performance and extreme leakage resistance, making it ideal for calibration, metrology, and sensitive electronic testing with Fluke 5440 Series calibrators.

Technical Specifications

• Thermal EMF: Less than 1.3 µV per °C (measured at Tellurium Copper Alloy 145 five-way binding post, half hard)


• Leakage Resistance: Greater than 1.0 × 10¹³ Ω per 100 ft at 45 °C and 75% R.H. (between conductors or between conductor and shield) Cable Assembly


• Configuration: Two 24 inch (61 cm ± 2.5 cm) short leads and one 48 inch (122 cm ± 2.5 cm) long lead


• Cable Type: Two-conductor shielded (Belden 8719 or RG-58/U equivalent)


• Signal Conductors: 16 AWG tinned copper, 19 × 29 stranding (5440A-7003 model) or AWG 20 stranded tinned conductors (5440A-7002 set) Connector Options Spade Lug Configuration (5440A-7003):


• Material: Copper spade lug with gold plating over silver, nickel-free


• Terminal Size: 1/4 inch (6.35 mm) diameter Safety Type Configuration (5440A-7002 set, 5440A-7004/7005 components):


• Connector Diameter: 4 mm


• Center Conductor: Tellurium copper


• Spring Tip: Beryllium copper


• Feature: Retractable spring-loaded hood

Key Features

• Dedicated shielded construction with separate guard/shield connection per lead


• Thermal EMF specification below 1.3 µV/°C ensures drift-free measurements across temperature ranges


• Ultra-high leakage resistance (>10¹³ Ω/100 ft) eliminates measurement corruption in high-impedance circuits


• Multiple connector styles accommodate varied terminal geometries on precision instruments


• Tinned copper conductors resist oxidation and corrosion

Typical Applications

• DC precision calibration and verification


• High-impedance metrology measurements


• Thermocouple and low-level voltage testing


• Temperature-sensitive electronic characterization

Compatibility & Integration Designed exclusively as an accessory for Fluke 5440 Series calibrators. Lead lengths support both bench proximity and remote test point access.