Buying task · ESD and bench safety
ESD and bench safety
How static damages electronics, what an ESD mat, wrist strap and common-point ground do, and the mains and battery safety rules for a home repair bench.
Short answer
Static discharge can destroy parts outright or leave hidden damage, and many components are susceptible below 100 V.[1] A basic ESD bench is a dissipative mat, a wrist strap with a built-in resistor, and a common-point ground tied to the outlet's ground wire. Two rules come before everything else: never wear a wrist strap near circuits of 250 V or more, and deal with lithium batteries before you open a device.[2]
What ESD control does
The ESD Association (ESDA) defines electrostatic discharge as the rapid, spontaneous transfer of static charge. It can cause catastrophic failures or latent defects, which show up later.[1] The core rule of the ANSI/ESD S20.20 standard is that every conductor at the workstation, including the person, is bonded to a known ground.[3]
A basic home ESD bench
| Part | What it does | What to look for |
|---|---|---|
| ESD mat (worksurface) | Lets charge drain away from boards and tools | A stated resistance to ground within ESDA's range for worksurfaces, 1 megohm to 1,000 megohms[2] |
| Wrist strap | Keeps you at ground potential | A cord resistor, most commonly 1 megohm, rated at least 1/4 W and 250 V[2] |
| Common-point ground | Joins the mat and strap to one ground | ESDA prefers a connection to the outlet's equipment ground, the third wire[2] |
If a mat does not state a resistance to ground in that range, do not count it as part of your ESD setup, however heat-resistant it is. The ESD bench setup guide walks through the connections.
Grounded soldering tools
A soldering tip touches sensitive pins directly, so the station's grounding matters. Hakko and JBC publish tip-to-ground resistance under 2 ohms and tip-to-ground potential under 2 mV for their stations.[4][5] In Japan, Hakko grounds the three-conductor version of its FR-301 desoldering tool to prevent electrostatic damage to components, and also sells a two-conductor version.[6]
Do not call a two-prong tool ESD-safe unless its maker publishes figures that support it. Few marketplace listings publish these figures; treat a missing one as unknown, neither a pass nor a fail.
Mains and battery safety
- Wrist straps and mains do not mix. ESDA says wrist straps must not be used if you will be exposed to circuits of 250 V or more.[2]
- Lithium batteries first. iFixit's ROG Ally battery guide says to drain the battery below 25% before starting, because a charged lithium-ion battery may catch fire if damaged.[7] Follow the battery steps in your own device's guide.
- Disposal. The EPA says lithium-ion batteries, and devices that contain them, do not belong in household trash or recycling bins. Take them to battery recycling or household hazardous waste collection, tape the terminals or bag each battery, and contact the maker if a battery is damaged.[8]
How to choose
- A mat that states its resistance to ground, big enough for your boards and tools.
- A wrist strap with a 1 megohm cord resistor.
- A common-point ground cord designed to connect to the outlet's ground.
- Grounded tools, preferably with published tip-to-ground figures.
For the rest of the bench, see soldering stations and the measurement tools overview.
Everything in this topic
Guides
- How to set up an ESD-safe benchGives a standards-based ESD setup for a home repair bench, the common mistakes, and when you must not wear a wrist strap.
Common questions
How do I ground an ESD mat at home?
Connect the mat's ground cord to a common point ground that ties into the outlet's equipment ground (the third wire), which the ESD Association describes as the preferred connection. Use a ground cord or plug made for ESD mats rather than an improvised wire. More in How to set up an ESD-safe bench
What resistor should an ESD wrist strap have?
The ESD Association says the cord resistor is most commonly one megohm, rated at least 1/4 watt with a 250-volt working voltage. More in How to set up an ESD-safe bench
Is a silicone soldering mat ESD-safe?
Not unless its maker states a resistance to ground in the ESD range. The ESD Association puts ESD worksurfaces at 1.0 x 10^6 to 1.0 x 10^9 ohms to ground; heat resistance is a different property. More in How to set up an ESD-safe bench
Should I wear a wrist strap when working on mains?
No. The ESD Association says wrist straps must not be used if you will be exposed to circuits of 250 volts or higher. More in How to set up an ESD-safe bench
Do I really need ESD protection for hobby repair?
If you handle bare boards and chips, it is simple insurance. The ESD Association notes that many components are susceptible to discharges below 100 V and that damage can be latent, showing up only later. More in How to set up an ESD-safe bench
Questions
Do I need an ESD mat for home electronics repair?
If you handle bare boards and chips, it is a sensible precaution. ESDA notes that many components are susceptible to discharges below 100 V and that ESD can leave latent defects that show up later.[1]
How do I ground an ESD mat at home?
Through a common-point ground. ESDA's preferred connection runs from the common point ground to the equipment grounding conductor, the third wire of a grounded outlet. Follow the mat maker's instructions and never improvise a connection.[2]
What resistor should an ESD wrist strap have?
ESDA says the cord resistor is most commonly one megohm, rated at least 1/4 watt with a working voltage rating of 250 V.[2]
Can I wear a wrist strap while working on mains equipment?
No. ESDA says wrist straps must not be used if the operator will be exposed to electrical circuits of 250 V or higher.[2]
Is a soldering station with a two-prong plug ESD-safe?
Do not assume so. Look for published tip-to-ground figures, such as the under 2 ohms and under 2 mV that Hakko and JBC give for their stations, and prefer a grounded three-prong plug.[4][5]
How do I dispose of an old lithium-ion battery?
Not in household trash or recycling. The EPA says to take it to battery recycling or household hazardous waste collection, with the terminals taped or the battery bagged, and to contact the maker if it is damaged.[8]