Elizafox's Ramblings

I haven't found a comprehensive guide online to being safe in electronics, other than giving out fragments of tips. There's obvious things like “don't touch the hot part of the soldering iron,” but there are a lot of other things not mentioned.

This will be a post I will update as I find more information on the subject, and find things people may not be aware of when doing electronics work.

Failure to abide by safety guidelines may result in grave injury or death. Electronics is largely a safe hobby, when safe procedures are followed. Make safety a habit. You don't want to end up like this (content warning: graphic PSA).

This post is not comprehensive. Use common sense. If you don't know better than, say, don't touch the hot end of an iron, you should probably have a few more birthdays before you do electronics work.

This all may seem like a lot, but trust me: it becomes automatic with practise.

Feedback is welcome for this post. Contact me for any additions, clarifications, or fixes you would like to see!

Solder safety

• Never put solder in your mouth, not even for a moment, not even to hold it
• Do not eat or drink anything whilst soldering
• Wash your hands after soldering thoroughly
• Only solder in well-ventilated areas
  • Lead is not in solder smoke as it is not hot enough to vaporise the lead; however, tin may be present and is an inhalation hazard
  • Note: tin is always present in lead-free solders
• Do not allow pets to chew on or eat solder
• Keep solder out of reach of children

Flux safety

• Many fluxes are corrosive or irritating to skin; do not allow flux to contact your hands for long periods
  • Wash off all flux thoroughly if it gets on your hands
• Clean all excess flux off your boards and work area with isopropanol (rubbing alcohol)
• Do not allow pets to consume flux
• Keep flux out of reach of children

Soldering iron / hot equipment safety

• Never grab the soldering iron or hot solder sucker by the end
• Do not leave hot equipment unattended for any period
• Have a non-flammable holder for the equipment around at all times
• If using a sponge, ensure it is wet
  • Do not hold the equipment to any point on a sponge for long periods
• Never use temperatures above what you need for the work at hand
• If a hot piece of equipment falls, let it fall; under no circumstances should you ever try to grab it
• Assume hot equipment is always hot; verify the equipment is not hot before servicing in any way (tip change, etc.)
• Use care around hot equipment; do not rush or try to hurry
• Work should never be performed on an energised circuit
• Wear only cotton or wool garments when working with hot equipment; other garments may melt and burn the skin upon contact
  • Don't work with hot equipment without wearing jeans and a shirt; I know it sounds cute to solder in a skirt, but for safety's sake, please don't

Isopropanol (rubbing alcohol) safety

• Isopropanol is highly flammable; keep away from all hot equipment and sparks of any kind
• Do not ingest isopropanol; I'm not sure I have to include this one, but I've been asked if it's toxic...
• Never use isopropanol on any energised circuit
• Remove all excess isopropanol from surfaces and allow to dry before energising a circuit
• Prolonged contact with skin may result in dry skin; try to avoid skin contact with isopropanol

PCB safety

• Work should never be performed on an energised circuit
• High voltage and low voltage must be separated in any design, with isolation at all connection points
  • Drilled gaps in the board between high and low voltage are best when possible to avoid arcing
  • Traces, contacts, and pins must be spaced sufficiently apart to avoid arcing
  • Traces, contacts, and pins must be sized appropriately to the voltage and amperage; more voltage and/or more amperage means you need larger traces
  • Higher voltages always require wider traces, even at low current
• PCB edges can be sharp; use caution when handling PCB's
• Wash your hands after handling any PCB
• Discharge any higher-value capacitors in your circuit before work, especially those charged at higher voltages and above a millifarad
• Wear respiratory protection when sanding PCB's, and remove all dust wifh HEPA filter vacuums
• Do not store PCB's in bulk in bags; this can result in toxic and dangerous dust from PCB friction collecting inside the bag

Voltage/amperage safety

• Only work around energised circuits with dry hands
• The breakdown voltage of dry skin is around 20-40 volts (although can be as high as 50 volts for very dry skin); above this, power can begin to conduct through the skin; use care around voltages above 20 volts,
  • The threshold amperage at which you can still let go of a current source is around 6 milliamps (however, this will vary by person); use special care when this much amperage is involved with 20 or more volts
  • As a general rule, to set good habits, use caution with any voltage over 20 volts, and treat any voltage over 50 volts as inherently dangerous, regardless of current
• Do not attempt to directly use mains voltage in your project without knowing exactly what you are doing
• Use only components rated for the voltage your circuit will run at
• Ensure your wire gauge is sufficiently thick for the voltage and current going through it; here is how to size your wire correctly

Battery safety

• Do not heat, puncture, or incinerate any battery; fire may result
• If a battery will not charge, and it is not the charger at fault, do not attempt to force it to charge; discard the battery
• Do not attempt to charge a battery run that has completely discharged (below 2 volts for a Lithium-ion battery)
• If a battery begins to smoke, or emit a smell like acetone, metallic, or sweet, carefully remove the battery place immediately into a flame-resistant container and remove the battery to the outdoors; allow symptoms to dissipate before disposal
• If a battery has begun to swell, carefully remove the battery and place immediately into a flame-resistant container (preferably with sand); dispose of it at an e-waste site
• Dispose of all batteries at e-waste sites; never throw away a battery, or place them into a recycling bin
• Battery fires should be extinguished with an ABC fire extinguisher or sand; remove the electronics outdoors immediately after extinguishing, as the battery may reignite
• Use only insulated tools on equipment with large capacitors or higher voltages
• Always assume if the voltage is high, the amperage is high

Other safety

• Never work on energised equipment
• Do not attempt to disassemble a microwave unless you know what you are doing; there is a capacitor inside that may be charged to lethal levels
• Do not attempt to service a CRT unless you know what you are doing; there is a flyback capacitor inside charged at potentially lethal levels; always ground the CRT before use
• If dealing with lasers, always wear eye protection
• When checking for smells, waft, do not smell directly

— Elizabeth Myers (Elizafox) Fedi (elsewhere): @Elizafox@social.treehouse.systems Tip jar: PayPal || CashApp || LiberaPay