Grounding a soldering iron and testing tip-to-ground resistance
An ESD-safe soldering station lives or dies by the grounding of its tip. This guide explains how to bond your soldering iron and station to a common point ground, how to measure tip-to-ground resistance per IEC 61340-5-1, and how to stay under the 2 ohm limit.
View soldering stationsWhy must the soldering tip be grounded?
With every joint the soldering tip touches the leads of electrostatic-sensitive devices directly. If the tip is not properly grounded, static charge or leakage current from the heating element can flow through the tip into the part and destroy it, either instantly or through latent damage.
A low-resistance path from the tip to the common point ground drains charge in a controlled way and keeps the voltage at the tip low. IEC 61340‑5‑1 therefore specifies a defined tip-to-ground resistance and a limited leakage voltage.
What limits does IEC 61340-5-1 set?
Two figures matter for a soldering iron: the resistance from tip to ground and the leakage voltage (potential) at the tip. Both are measured with the tip hot, because the values shift with temperature.
The widely quoted 2 Ω figure comes from common manufacturer specs and test routines; what counts is a value that is low and stable. If resistance climbs to several ohms the tip is usually oxidised or the ground path is broken.
How do I test tip-to-ground resistance?
You only need a low-ohm milliohm or multimeter and a millivoltmeter. Switch the station on and bring it to operating temperature, because cold and hot readings differ.
- Switch on the station and let it reach working temperature (for example 350 °C).
- Clip one test lead to the bench common point ground.
- Hold the second lead to the hot tip using a test adapter or heat-proof clamp.
- Read the resistance: target < 2 Ω. Then measure leakage voltage in the mV range.
- Record the values with date and station ID.
How do I keep the ground reliable over time?
The station ground must run to the same common point ground as the bench mat and wrist strap. Only then do all conductive elements sit at one potential and no equalising current flows through the component.
- Bond station, mat and wrist strap to ONE common point ground.
- Screw the station ground lead down firmly, do not just plug it in.
- Tin the tip regularly - a clean tip means low resistance.
- Measure tip-to-ground resistance and leakage voltage periodically and log them.
- Replace damaged or heavily oxidised tips promptly.
Frequently asked questions
How high may the tip-to-ground resistance be?
The common requirement is a low value below 2 ohms, measured at the hot tip against the ground point. A clear rise usually means an oxidised tip or a broken ground path.
Why measure with the tip hot?
Resistance and leakage voltage change with temperature. Since soldering happens hot, only a reading at operating temperature is meaningful.
Does the tip need a 1 MΩ resistor like the mat?
No. The tip is grounded hard and low-ohm (< 2 Ω) so no residual voltage sits on the part. The 1 MΩ resistor applies to person and surface grounding, not the tip.
How often should I test the ground?
For sensitive assembly a short daily check is advisable, and at least after every tip change. Log the values to catch wear early.
Need an ESD-safe grounded station?
We supply ESD-safe soldering stations, grounding sets and test tools for tip-to-ground resistance, matched to IEC 61340-5-1.
Standard-tested
Stations meet the requirements of IEC 61340-5-1.
Low-ohm ground
Tip-to-ground resistance kept below 2 ohms.
Measurably safe
Resistance and leakage voltage documented and verifiable.
Expert advice
ESD specialists help with selection and testing.