ESD hand lotion: why dry skin impairs personnel grounding
Dry skin is a poor conductor: a high contact resistance builds up between wrist and strap, and the person-to-ground limit of 3.5 x 107 Ω set by IEC 61340-5-1 is exceeded. A silicone-free, lanolin-free ESD hand lotion moisturises the skin, improves contact and leaves no residue on assemblies.
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Why does dry skin impair personnel grounding?
A wrist strap drains charge only through its contact area with the skin. Moist skin conducts well because sweat carries ions; dry, flaky skin acts like a thin insulating layer. Contact resistance rises, and the path through strap and ground cord can exceed 3.5 x 107 Ω even with strap and cord in perfect order.
The grounding path puts the cord resistor (usually 1 MΩ), the strap and the skin interface in series. Only the skin interface varies with person, season and day, which makes it the usual cause when a sound strap fails the test.
How do you recognise grounding problems caused by dry skin?
Typical signs are tester readings just above the limit, or values that vary between attempts, while the same strap passes on a colleague. Continuous monitors give short alarms without a visible defect, often in the morning and in the heating season. After a few minutes of wear the reading often falls on its own.
Rule out the strap first, then treat the skin
- Check the strap with the tester's test plug or on a colleague.
- Check snap, cord and fit: the strap must sit snugly on bare skin.
- Only then apply lotion and repeat the test.
Wrist strap testing and careHow to test strap, snap and cord and spot wear in good time.
Read the guideWhy not use ordinary hand cream in the EPA?
Ordinary hand creams often contain silicones, lanolin or mineral oil. Lanolin and mineral oil form a film that tends to worsen contact with the strap. Silicone transfers via the fingers onto PCBs, where even traces disturb solder wetting and coating adhesion. ESD hand lotion is dissipative, free of these ingredients and absorbs without leaving a residual film.
| Property | Ordinary hand cream | ESD hand lotion |
|---|---|---|
| Silicones | often included | not included |
| Lanolin, mineral oil | often used as emollients | not included |
| Contact with the wrist strap | grease film can insulate | improves skin conductivity |
| Residue on assemblies | risk of soldering and coating defects | low residue, non-corrosive |
| Surface resistance | not specified | dissipative, 106 to 109 Ω |
How do you apply ESD hand lotion correctly?
A small amount is enough. Rub it in mainly where the strap sits, around the wrist, and on dry areas of the hands. Let it absorb fully and wipe off any excess with a towel. Only then carry out the grounding test and start work.
- Timing: before the shift and before the grounding test, not afterwards. The logged reading should reflect the condition in which work is actually done.
- Quantity: a little is better than a lot, otherwise a moist film ends up on components and tools.
- Gloves: let the lotion absorb completely before putting on ESD gloves or finger cots.
- Where to use: hands and wrists only, keep away from face and eyes.
What can ESD hand lotion not replace?
ESD hand lotion improves skin contact; it does not ground anyone. Without a connection to the common ground point via wrist strap, or via footwear and flooring, it drains no charge. Nor does it make up for torn straps, broken cords or worn snaps.
Frequently asked questions
Can ordinary hand cream be used instead of ESD hand lotion?
Not in an EPA. Silicones, lanolin and mineral oil in many creams can worsen contact with the wrist strap and leave residue that causes soldering and coating defects. Use only a lotion compatible with your process.
When should ESD hand lotion be applied?
Before the shift and before the grounding test, so the logged value matches the working condition. Reapply after hand washing if needed, and let it absorb before touching components, tools or gloves.
Does ESD hand lotion replace the wrist strap?
No. It only improves the skin-to-strap interface. Charge is drained only through a tested connection to the common ground point, via wrist strap and cord or via ESD footwear on dissipative flooring.
Which care products suit your EPA?
Silicone-free ESD hand lotion and wrist straps for personnel grounding to IEC 61340-5-1.
Standards-based
Limits according to IEC 61340-5-1.
Process-compatible
Silicone-free, lanolin-free care for production.
Measurable
Effect verifiable at the wrist strap tester.
Selection help
We help you choose the right products; technical details are clarified with the manufacturer.