There are cases when the owners of a TV aerial or sat wish to cut or slice the coaxial cable that is feeding energy to the aerial or satellite dish. Considering that electrical power runs through this cable, many think that it’s risky to try cutting this cable. But, is it really the case? In the lines that follow you will find out everything, you need to know on this matter. So, if you’re looking to shorten a coax cable that is too long, at the end of the article you will know whether the operation is risky or not.
Whatever you do, do not take this matter lightly. We are talking, after all, of cables that have a continuous stream of electrical power running through them. So, if you want to cut such a coaxial cable, turning off the power for the appliance it is connected to is the best way to go. We are not however, talking here about electrical cabling.
Let your family know that the power will be down for a small amount of time and turn off the power supply of the appliance. This way you make sure that your cable is no longer supplied with energy during the operation. If you have any concerns regarding the operation, you can always contact a reliable electrician or aerial fitter. It is even recommended to do so if you don’t know the best means to complete the operation in a safe manner.
Whatever you do, do not take this matter lightly. We are talking, after all, of cables that have a continuous stream of electrical power running through them. So, if you want to cut such a coaxial cable, turning off the power for the appliance it is connected to is the best way to go. We are not however, talking here about electrical cabling.
Let your family know that the power will be down for a small amount of time and turn off the power supply of the appliance. This way you make sure that your cable is no longer supplied with energy during the operation. If you have any concerns regarding the operation, you can always contact a reliable electrician or aerial fitter. It is even recommended to do so if you don’t know the best means to complete the operation in a safe manner.
Is there any current in the cables feeding TV and radio aerials?
This type of cables cannot work if the electric current is not going through them. Thus, they need electrical power to run through them so they can do their job right. The job of your aerial is to get radio frequencies that run across the atmosphere and then transfer them to the cable that goes to your TV. More precisely, the signal captured by the aerial is actually alternating current electricity. But its frequency is much higher than of your home’s electrical supply. However, this won’t make cutting a coaxial cable an impossible task. The voltage going through the cable will be much lower than that captured initially by the aerial.
Is there any current in the coaxial cables powering satellite dishes?
The functioning principle of this coaxial cable is the same as that presented earlier, in the case of TV and radio aerials. The satellite dish will capture signals coming from a satellite providing TV services and will transmit the signals to a satellite receiver through a coaxial cable. The current is yet again involved to make this aspect happen. In most cases, a Freesat or Sky box is used or a TV that is equipped with a satellite tuner.
However, satellite dishes work in a different manner than aerials. When signals are captured by the satellite dish, they are first beamed down to earth before reaching the satellite receiver. Because of this, the satellite LNB will have to amplify the signal before sending it to the receiver, as it comes at a very low level. The LNB won’t be able to perform this operation without current. Thus, the satellite receiver will provide DC voltage in a continuous manner to the LNB. This means, usually, 13V DC, and in the case of Quad LNBs a value of 18V DC.
The values mentioned earlier are much higher than the passive cables used for TV and radio aerials, but, even so, they are far from the limit meant to cause harm. Thus, these numbers should not scare you. Still, if you do get an electric shock from such a coaxial cable, you will feel it, without a doubt. This usually happens because, in most cases, when working on such a cable you’re anchored to a ladder made out of metal. And we all know that metal is a good current conductor. The “shock” feeling is more intense during rainy weather, as water makes it worse and propagates it faster. Again, all of this won’t cause you any harm, but it will be unpleasant and will trigger a level of discomfort.
However, satellite dishes work in a different manner than aerials. When signals are captured by the satellite dish, they are first beamed down to earth before reaching the satellite receiver. Because of this, the satellite LNB will have to amplify the signal before sending it to the receiver, as it comes at a very low level. The LNB won’t be able to perform this operation without current. Thus, the satellite receiver will provide DC voltage in a continuous manner to the LNB. This means, usually, 13V DC, and in the case of Quad LNBs a value of 18V DC.
The values mentioned earlier are much higher than the passive cables used for TV and radio aerials, but, even so, they are far from the limit meant to cause harm. Thus, these numbers should not scare you. Still, if you do get an electric shock from such a coaxial cable, you will feel it, without a doubt. This usually happens because, in most cases, when working on such a cable you’re anchored to a ladder made out of metal. And we all know that metal is a good current conductor. The “shock” feeling is more intense during rainy weather, as water makes it worse and propagates it faster. Again, all of this won’t cause you any harm, but it will be unpleasant and will trigger a level of discomfort.
Communal TV systems are different
If you’re TV is connected to a communal TV system, you should know that this system is different from conventional TV systems. The difference is set by the fact that one single system can feed a high number of TV equipment. For example, if there are 100 flats in the building where you live, all 100 will be fed by the same communal TV system. Thus, the number of amplifiers and other pieces of equipment will be much higher and, therefore, there will be an accumulated voltage effect in this case.
So, if you end up working on a communal TV system, you may end up affecting the functionality of several TVs, if not of all of them. In other words, your neighbours may get out of their homes to yell at you that their TVs are not working any longer. Making adjustments, in this case, could be more difficult, due to the large number of users connected to the same system. If you don’t have too many neighbours using the same system, it may be worth talking to them, to all of them, and get their approval while also setting a time and date for the operation to take place.
So, if you end up working on a communal TV system, you may end up affecting the functionality of several TVs, if not of all of them. In other words, your neighbours may get out of their homes to yell at you that their TVs are not working any longer. Making adjustments, in this case, could be more difficult, due to the large number of users connected to the same system. If you don’t have too many neighbours using the same system, it may be worth talking to them, to all of them, and get their approval while also setting a time and date for the operation to take place.
Some electrical shocks are not dangerous, apparently
According to some specialists, the human organism is capable of absorbing electric shocks of up to 50V, without risking significant harm or injuries. Thus, considering the values mentioned earlier, the value of the voltage you’ll subject yourself to will not be in the dangerous range. Precisely because the upper limit is 50V, many systems are made to operate below this value so they won’t represent a threat to people’s lives. POE systems or Power over Ethernet range in the 24 to 48V area, as an example. Of course, this upper limit is a generally-set value and may not apply to everybody. Some may be more sensitive than others, so precaution is advised.
Poor or faulty electrical installation may represent a greater risk for shocks
So far, we talked about systems and installations that are done according to standards. If the electrical installation you’re about to work on is faulty or poorly set, the risk you may be facing is greater. In other words, your coaxial cable may run current of a higher voltage than in a normal situation. The good news is represented by the fact that there is no outer case made out of metal, as it happens in the case of a fridge or washing machine. Also, in most cases, there isn’t an earth connection present in the main plug.
The conclusion is that the aerial plus is the only piece of metal exposed outside the TV that could represent a degree of risk. This is translated into the possibility of an unwanted voltage to reside in this particular piece of metal. However, most TV types, including LED and OLED, rarely go anywhere near a voltage that is high and dangerous.
You should also know that even a poor electrical installation is incapable of delivering high voltage values. This could be possible only in the case of a very old installation that is away from today’s range of standards. Systems used nowadays generally include an MCB or RCD that will immediately cut down the power if anything out of the ordinary is sensed.
The conclusion is that the aerial plus is the only piece of metal exposed outside the TV that could represent a degree of risk. This is translated into the possibility of an unwanted voltage to reside in this particular piece of metal. However, most TV types, including LED and OLED, rarely go anywhere near a voltage that is high and dangerous.
You should also know that even a poor electrical installation is incapable of delivering high voltage values. This could be possible only in the case of a very old installation that is away from today’s range of standards. Systems used nowadays generally include an MCB or RCD that will immediately cut down the power if anything out of the ordinary is sensed.
What you can do to stay on the safe side
Even if the cases in which you can get hurt are quite rare and they mean the occurrence of particular conditions, you should always take proper safety measures and precautions. Because you are working with electric power, safety is advised at all times, no matter how small the voltage is. So, here is what you can do to make sure you’re working in safe conditions:
- All TV equipment should be switched off before you start working on the cables;
- It is strongly recommended to also switch off the electric supply leading to all your equipment in the house;
- Utilise cutters and tools that are made to provide adequate insulation against electric current. An adequate set for an electrician will provide protection of up to 1000V;
- You can increase the level of safety by earthing your TV system. You can do so on the spot, with the help of an earth bonding. This will allow you to work on the system without any risks involved;
- If you have any doubts about how to handle this matter properly, you can always hire a trained professional.
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