It’s possible to cut or splice your coaxial cable to make a longer cable that reaches your TV receiver, but what are the chances that you’ll get an electric shock? Splicing cables is delicate work and requires precision and following proper procedures, but almost anyone can do it safely.
If you’re not sure whether your coax cable is live, always make sure you turn off the electricity to be safe, or use a local aerial company to do it for you. If you’re not sure that you can splice the coax cable correctly or safely, always consult with an electrician.
Does your TV aerial cable carry current?
By their very nature, aerial cables carry a current. TV aerials work by capturing radio waves from the air and transmitting them through a coaxial cable down to your television set. Through this process, the cable is using alternating current electricity, a higher frequency than your mains electrical supply.
Don’t let this scare you away, though. The voltage coming from a coax cable from your TV aerial is very low. If you touch the live current coming from most aerials, you likely won’t feel it, and it won’t cause you harm. Most aerials can’t get enough signal to do any damage if you touch them while they’re live.
Can you get an electrical shock from satellite dish coax cables?
Satellite dishes work differently from aerials in that they get their signals from satellites in Earth’s orbit instead of waves in the air. Many people have a Sky box or TV with an integrated satellite TV tuner. A satellite dish has a different current because the signals coming down from the satellites are received at low levels. The signal needs to be amplified by the satellite LNB before it goes to your TV receiver. To that end, a continuous, direct current (DC) voltage is fed to the receiver to power the LNB. The voltage is an average of 13V DC.
The voltage is higher than passive TV cables, but it is still low enough that it will not cause any harm if you touch it.
However, you might feel a current when you’re connecting cables at the satellite dish, which is relatively common. You’re probably standing on a metal ladder or holding something metal when it happens. This is also likely in wet weather. More than likely, you still won’t be harmed by the current, but you should take precautions so that you don’t fall. If you can, turn off the satellite dish or disconnect it from the receiver so that the current isn’t live in the cables while you work on it.
How does it work with communal TV systems?
Communal systems feed multiple TV systems instead of only one or a couple in one house. Communal systems can be connected to 50 or 100 homes with that many or more TV systems. Combine this with the TV equipment, amplifiers, etc., and the voltage will start building up in the cables.
The chances that the cables will give you an electric shock are still low but don’t take any unnecessary risks. Communal systems need to be connected to an earth connection for safety, but some aren’t, especially older systems that weren’t installed correctly.
CAI Device Limits
The CAI has a safety limit of up to 5 pieces of equipment connected to your TV system at one time. Once you reach 6 or more pieces of equipment, you need to earth the system or sign a disclaimer waiving liability for the installer.
With 6 or more pieces of AV equipment connected to your TV system, the touch current can build up, which can potentially cause injury if someone were to touch it. The injury isn’t only from the current, but from too much equipment that could fall over and cause harm.
The 5-piece limit is not a regulation, but the measure does help limit legal liability in case of an accident.
Safe Up To 50V
Researchers have noted that humans can absorb up to 50V at one time without injury or harm. Many systems now operate up to 50V to get the most power while risking little damage. Many electrical transformers have a voltage below 50V for safety, and the ring circuit on your telephone, which makes it ring when you have a call, is 50V. Any device or cable running at or below 50V likely won’t cause any harm or give you a strong electrical shock.
However, if the system is not installed correctly, you could have high currents on your cables. Also, some old-style televisions, like Cathode Ray Tube (CRT) TV’s have voltages around 25,000V. Another problem is that your TV, unlike other appliances in your house, is not enclosed in a metal casing. Often the only exposed metal is the aerial plug, which can develop unwanted voltage. Fortunately, most modern TVs are designed safer than older-styles and do not reach extremely high voltages.
Poor installation of your device can cause high voltage in the coax cable, but this is more common in very old setups. These days, most new systems include RCDs and MCBs that cut the electrical supply when something is wrong or unsafe.
How can you stay safe from electric shocks?
While in most circumstances, the current or voltage is too low in coax cables for you to notice or feel them, you should still practice all the proper safety precautions when working. Splicing coaxial cables can still be dangerous if you do something wrong.
Start with the obvious by turning off all the TV equipment.
You also want to turn off the electric supply.
Make sure you use cutters or hand tools that have proper electrical insulation.
Earth the TV system for safety.
Hire a professional if you’re not sure you can handle it yourself or handle it safely.
If you’re on a ladder, harness yourself.
Don’t work on the aerial or satellite dish outside in wet weather.
Following a few extra steps of safety makes sure you can splice your coax cables to your heart’s content without putting yourself at unnecessary risk.