Electricity, not so shocking: Part 2 of 2
In this 2nd part I add to that knowledge by detailing some skills to splice cables, replace connectors. These skills can be used to customize or repair cables or power strips. As well a few other bits of knowledge worth having.
One of the first things to know is about polarization. I covered this a bit in part one but feel it's worth providing a bit more detail on the subject.
Polarized AC plugs are electrical plugs that have two prongs of different sizes, with one prong being wider than the other. The wider prong is the neutral prong (white wire), while the narrower prong is the hot prong(black wire). Polarized plugs are designed to fit into polarized outlets, which have slots of different sizes to match the prongs on the plug. The purpose of polarized plugs and outlets is to ensure that the electrical current flows through the circuit in the proper direction for the device/appliance being connected and reducing the risk of electrical shock and fire.
It is important to note that not all electrical outlets are polarized, and not all plugs are polarized. Some older outlets and appliances may have non-polarized plugs, which can be inserted into the outlet in either orientation.
| NEMA 5-15 receptacle. |
As mentioned before, polarization can be indicated by color or other visual or physical markers on the cable. For AC cables you will have white for neutral, black for hot and green for ground.
This chart can be used a general rule of thumb when attempting to identify wires. But know that it's not always certain and you should always double check.
Tools for basic electrical work:
In order to do basic electrical tasks you should have some tools to make things easier and ensure you do a good job.
-Voltmeter/Multimeter
Having a good multimeter is a great tool for problem solving. Checking continuity is important when splicing wire or replacing plugs. Having one that can serve as a ammeter (measure amperage) is an added bonus.
-Wire Stripper/Crimper tool
There are various styles and options but this one is great being that it's multi-function.
-Soldering iron
You don't need anything fancy for basic work. This is a simple one that can handle simple DIY tasks.
-Flux
Essential to get a good connection when soldering.
-Butt splice connectors
Good to have in all sizes for various gauge wiring. These are quick and secure method for splicing.
-Heat shrink tubing
Get a collection of sizes
-Heat gun
Best option for heat shrink tubing but not essential. A lighter will do in a pinch.
-Electrical tape
Get the good stuff from 3M.
-Screwdriver
The 6-in-1 style linked is great to have while offering 6 driver options in one package while not having tiny bits to worry about loosing.
Splicing Wires
Splicing wires can be helpful to shorten power cables or make a Y-split cable as I've discussed HERE. This can also translate to DC wiring and making your own custom DC cables. (Like D-Tap, barrel plugs, etc..)
The video below shows covers five different way to splice wires but the two methods I prefer are soldering and butt splice connectors.
The basic steps if soldering are:
- Cut the insulation around the wires at the end of each AC cable, using a sharp knife or wire stripper. Be careful not to cut the wires themselves.
- Twist the bare wires from each cable together to create a solid connection. Make sure to match the wires according to their color code (e.g., white to white, black to black, green to green.). If using heat shrink, remember to place your heat shrink tubing on the wires before making the connection.
- Apply flux to the connection.
- Apply solder to the connection. Just enough to to "tin" the connection.
- Once the bare wires are securely connected, you can wrap the splice with electrical tape or heat shrink tubing to protect it from the elements and ensure a secure connection.
- Check the continuity with a multimeter to confirm the hot and neutral are connected properly.
Another useful skill is replacing a plug on AC cables. This could be done due to damage or needing to shorten a cable. I often cut down the length of the cable on power strips and UPS as they often come much longer than needed and will be used in conjunction with a stinger/extension anyway. Just makes for less work managing cables.
The steps for replacing a plug on an AC cable:
- Unplug the AC cable from the wall outlet.
- Use a wire stripper to remove a small section of the insulation from the end of the AC cable, exposing the bare wire. Be careful not to cut the wires themselves.
- Locate the screw terminals on the new plug and loosen them using a screwdriver.
- Match the bare wires according to their color code (e.g., white to white, black to black, green to green. This can also be black to the brass connector and white to the silver connector) and insert the bare wires into the appropriate screw terminals on the new plug.
- Tighten the screw terminals securely using a screwdriver.
- Test the new plug to make sure it is secure and the wires are properly connected.
I find it helpful to use these lighted plugs as they help give a visual indication that an outlet has power.
Surge protectors
I was asked by a few people to cover surge protectors. In the most basic explanation, they protect your electronic devices from voltage spikes by redirecting excess voltage away from your devices and into the ground. These voltage spikes can be caused by a variety of things, such as lightning strikes, power outages, and problems with the electrical grid. Without a surge protector, these voltage spikes can damage your electronic devices and potentially cause them to stop working. It is possible to have an ungrounded surge protector but it's not likely to provide as much protection.
They can often be found integrated into power strips and UPSs. You can also get them as standalone units. Surge protectors are rated based on their ability to absorb and redirect excess voltage. This rating is typically expressed in joules, which is a measure of energy. The higher the joule rating of a surge protector, the more energy it can absorb before it fails. In addition to the joule rating, surge protectors may also be rated based on their voltage protection rating (VPR) and their response time. The VPR indicates the level of voltage that the surge protector can handle before it begins to divert excess voltage away from your devices. The response time, on the other hand, refers to the amount of time it takes for the surge protector to begin redirecting excess voltage.
Volt and joule are two different units of measurement that are used to describe electrical power and energy, respectively. A volt is a unit of electrical potential difference, while a joule is a unit of energy.
In practical terms, a volt is the measure of the force that drives the flow of electricity through a conductor, such as a wire. The higher the voltage, the greater the force, and the more electricity will flow through the conductor.
On the other hand, a joule is a measure of the amount of energy that is required to perform a certain amount of work. For example, the energy required to lift a 1-kilogram object a distance of 1 meter is 1 joule.
You should only consider surge protectors rated at or above 500joules.
In closing:
Having a basic knowledge and understanding of the basics of electricity is a vary valuable tool. I've only touched on a few key elements that might help you on set and working the photography or film world but these things can translate into your home life as well. I suggest getting a book like this one to help further your education on this subject and gain the confidence to tackle other projects. After you've learned the basics of single phase 120VAC you can begin to learn about three-phase power.
Disclaimer: Everything covered above pertains to electrical system in North America and specifically the United States with single phase 110-120VAC. Other countries vary. I'm not a licensed electrician, but have many years of experience working first hand with basic electrical wiring on and off set. I've spent the time learning the details, proper safety required and am aware of the risks involved. Carelessness with electricity can result in serious injury or death.
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