Health and Safety
Background information
This page covers practical health and safety which may seem common sense to some but may not occur to others. My Digital forensics tutor once said "The reason you wear gloves when handling devices, is not because of the device its self but when it has been" Basically, it means people hygiene can be real nasty, and you have no idea what's the drive been exposed to or who touched it with which part of their body. Wearing disposable gloves just keeps helps keep you safe.
Electronics safety
"Not only will electric kill you, but it will hurt the entire time you're dying - Danger signs"
Depending on where you are in the world voltages differ greatly but what they do have in common is there ability to ruin your day if you don't treat when with respect
In the UK and most of Europe runs around 240v at 50hz on household lines, with America running at around 120v at 60hz.
With that being said the biggest threat when working with electric is not the voltage but the amperage, even a few amps can cause serious issues within the body,
while voltage just causes pain (typically a lot). Voltage is still dangerous when handled without care, but is less likely to kill you when compared to amperage
with the average sized adult human having a resistance of around 70 - 100mille-amps with anything above that up to 1000 mile-amps being enough to cause your heart to stop
and or stop you breathing
anything above that is enough to launch you across the room and cause extreme internal heating.
devices such as TV, computer screens and microwaves can easily produce 100+ mile amps with microwave being typically 5000+, epically when they can be dissembled for repair.
the moral of the story is be careful when handling electronics, because nobody wants the thing that kills them to be a microwave.
The follow are some useful tips on how to safely handle electronics, both for you and the sensitive (often fairly expensive) tools and devices you're working with/on.
Working electrical circuits
- Using a multimeter to check the voltages of a component before working on it is recommended, even if the circuit is unpowered, as charge can remain in components for multiple days
in the case of large capacitors.
- Ensuring that you are in a safe environment when working with electronics extends beyond such electrical safety knowledge, it also includes making sure that you're working environment
is safe should you become unconscious for any reason, be it unrelated medical issue or electrical hazard. Consider for a moment this scenario
if you are working on a chair without sides and a solid concrete floor, and you receive a small but powerful electrical shock which briefly knocks you unconscious.
While the shock as not caused any real damage, but in your unconscious state you fell off your chair, hitting your head on the concrete floor causing a concussion.
Now picture the same scenario but with a chair with arm rests, the only way you can fall is either forwards likely landing on your workbench (much smaller fall)
or sideways, in which case the arm rests prevent you from falling off the chair. By implementing non-invasive safety measures, you can prevent further injury to yourself. - Never touch a person who is in contact with a live wire as you will also get shocked
- Learn CPR or keep instructions on how to preform it in a clear visible location
while this does not help if you're on your own but if another person is around they can preform it on you, or you can perform it on them, should your heart stop just to a shock or any other reason - Always use high-powered tools with the appropriate plug, which should contain a neutral,ground/earth,power/live, and wire (Blue, green, brown)(UK only)
- Ensure all probes are shielded as this prevents electrical current from damaging both you and the equipment.
- Unplug unused equipment
- wrapping the top 3/4 of a probe tape in electrical tape will likely prevent an electrical shock should you accidentally touch it when it's connected to a live part
- Clipping a probe to the ground point allows you to probe one-handed meaning your body never completes the full electrical circuit that often causes current to pass through
your heart. - Placing electrical tape over exposed components prevents shorts due to two components touching, also place the board on an insulated surface such as
rubber project mat prevents current running through the table surface - Make sure any exposed electronics are out of range of a separate working area such as a desktop computer, to avoid accidental contact when resting your arms on the work area
espically, if you have a small workspace - Circuit breakers are not fast enough to prevent current from destroying either you or your equipment if you accidentally short to ground
- Know what you're working with, if you don't know research it!, resources such as this exist for a reason.
- Ensure that all devices are operating within their rated power ranges and are properly grounded.
- Wear eye protection
- Do not wear metal jewellery such as rings, bracelets and necklaces in case it makes contact with a live circuit
- Tie back long hair, or remove dangling clothing such as ties, to avoid it touching or getting tangled within a device
- Avoid dragging feet on carpet, handling polythene (plastic) bags as this builds up a static charge which can damage/destroy ESD sensitive components as an electric static discharge(ESD) could occur.
- To discharge any static built up and avoid ESD, simply making contact with a grounded metal surface. These can be achieved by ground your workbench legs (if they are metal)
- By wearing an ESD bracelet, which can prevent ESD completely if grounded correctly.
- Never install/remove or modify a component when a device is powered on
- Use your common sense, if it seems like a stupid idea it properly is or at least required a bit more thinking and research to make sure you don't hurt and or damage you or your equipment
Working with capacitors and other high voltage containers
capacitor's can still hold a high charge typically days after power has been disabled, so it is considered best practice to always assume they are live and must be dealt with accordinglyOther items such as the flash on disposable cameras and certain parts of DVD, CD and VRC players can hold a similar amount of charge for multiple days
To check if these do have a charge in them a voltmeter can be used to probe the positive and negative terminals, to check the current level with it