3 phase electricity

Duffster03@hotmail.com is correct in pointing you towards gounding rather than a problem with 3 phase power, I,d give up my left arm to have 3 phase power in my home. Proper grounding is a big factor with hum and noise problems, especially with pro and high end audio equipment that usually employ 3 conductor grounded power cords and balanced inputs/outputs. I have installed sound systems in a few local bars and nightclubs in the past. One particular club I installed a sound system in, had an intermittant hum/static noise problem. I found that the problem was caused by the electrical sub-panel, feeding the sound system, did not have the neutral/ground buss bonded to earth ground. There was more than a 5VAC difference between the ground buss in the panel and a nearby water pipe due to the fact that the earth ground connection to the buss in the panel was being made through the current carrying neutral line. Most sub-panels in commercial buildings and service panels found in homes have the neutral connections and earth ground connections to the branch circuits connected to the same buss bar in the service panel. For proper gounding this buss bar must be tied to both the neutral line coming into building (or the main switch gear feeding a multiple sub-panel arrangement) and the ground line running out to the grounding stake outside the building, the grounding stake line is usually tied to the service panel box and a bonding screw or wire is used to connect the box to the buss bar. A few things you should check if you are having hum and noise problems are, make sure that you have a good connection to the grounding stake outside and that at least 30 inches of the stake is below the ground level. If you have an older home where the wiring is fed through greenfield flexible conduit, run a seperate ground wire between the outlets feeding power to your system and the service panel. Flexible conduit is a poor grounding conductor, especially as it ages and oxidizes between the flex joints. One last thing to try is, in the service panel, move all of the neutral lines feeding the branch circuits to the portion of the neutral/ground buss bar between to the main neutral line feeding the panel and the bonding screw/wire, and move all the branch circuit earthground wires to the other side of the bonding screw/wire. If you are not familiar with electrical wiring safty and codes it would be best to hire an electrician to do this. Hope this helps.

Get a PSAudio Power supply and properly ground it, even if that mean installing your own ground system. 2 or 3 phase power isn't an issue as long as the Power supply has enough source power. Example the PS1200 will accept 2 phases of 30 amp power and by removing the internal jumper you can isolate the ground (by installing your own ground grid.) No TV signals or extreneous information will be delivered to you powered devices. I AM AN ELECTRICAL ENGINEER THAT HAS TO DEAL WITH PROCESS CONTROL NOISE IN INDUSTRIAL ENVIROMENTS.

Well, not sure if I quite understand your response but... you and your neighbors will share the same secondary on the transformer. The neighborhood transformers only have the one secondary output coil, whether single phase, 2 phase, or 3 phase. There are multiple output secondary coil transformers, but they are very expensive and you won't find these in a typical neighborhood. However, if there is a transformer (underground pad-mounted, or pole mounted) at both sides of your property line it may be an advantage to be connected to one or the other. Depending on how many houses are on one TX. versus how many on the other TX. Not sure that a power company would make the change to the other TX. unless you changed your service entrance to the other side of your house. That can be very expensive. Anyway, normally a TX is sized according to the load to be applied, one house, four, or eight houses. Then the KVA rating is raised accordingly, this makes up for any voltage drop caused by overloading the TX. Now about being quieter because of your neighbors load, you might have something there. That's one for an engineer. Oh well, that's my two cents for this week, Skip.

If I am understanding you, then 3 phase is an opportunity, not a problem. It means you can select which secondary to be connected to on your local power transformer. One may be quieter than another due to what your neighbours are doing with theirs. Generally you are likely to get lower noise if you do not use the same phase as you nearest neighbours. This is because the noise added by your neighbours is attenuated by the length of the cable between you and them.

Albert Porter has 3 phase service, so he knows all about it. Ask him.

Is your power underground or overhead. Have been a lineman for Florida Power & Light for 12yrs. and now a lineman for a municipal power company. 4kv, 12kv, 23kv, and so on can be single phase, two phase, three phase. Most of the time when power is brought into a neighborhood it is a three phase system, but one phase will be sent to one part of a neighborhood, another phase to another part, and then the other... Normaly it is a single phase primary that energizes the coils in your particular transformer, then it converts your primary voltage (4kv, 12kv, 23kv) down to your 120v-240v for use in your home. Overhead primary systems can create a problem called TVI. Which is television interference. This used to be very common back when rabbit ears and antennaes were used for TV reception, it also caused hav'oc with HAM radio operators. The cause was the hardware on the poles were not properly tightened or became loose. Normally, going to the pole that your property was associated with, and one pole up the line from yours and one pole down the line from yours, and re-tightening the hardware fixed this problem. If you have underground power, then there is no problem with this type of interference. 3 phase, 2 phase, or single phase. All of the primary conductors are insulated. Now whether or not the overhead type system can cause interference whith a stereo system, other than FM reception, I would doubt it. I won't guarantee that, just because my knowledge is rather in a limited area. An electrical engineer could probably answer you more completely, as they are proficient in electrical theory. I am not saying you don't have a problem with your electrical system bacause I am a lineman, I am a stereo enthusiast myself. The problem very well could be in the electrical system of your home or equipment. Don't know if this puts your mind at ease with your power provider, but I hope it answers some of your qustions about 3 phase power. Sincerely, Skip.

If I remember correctly, all 4KV lines are 3-phase. This should not cause any problems for you. Much greater culprits are any motorized things in your home, dimmers and your cable connection. All of these can cause nasty noise on the line and/or ground loop problems.