ESB lines

JOHNPT

Can anyone tell me what are the red and white circular balls u can see on overhead power lines. There is some on the lines over the motorway around Dublin. Some people say they are so aircraft can see lines others say so birds can see them and dont fly into them and drop onto cars.

Also usually there is 5 lines together. Is each line made up of one cooper of wire or is there multiple cores in each cable. Is it always distributed in three phase ie 3 seperate phases and a neutral or when you see two overhead cables what are those cables composed of. Are they insulated


Thanks in advance for replies.

Jnealon

Correct the balls are for small aircraft etc.
Over head lines, 110-400kV, are usually made from aluminium with a steel core The steel stop them from sagging when they heat up and they are not insulated. There are usually 3 or 6 wires together, one for each phase. If the lines are close to a station, ie less than 2km you will see a single earthwire on the tip of the tower. In that case you will have 4 or 7 wires. I some cases there may be 2 earth wires

Davy

JOHNPT wrote: »

Can anyone tell me what are the red and white circular balls u can see on overhead power lines. There is some on the lines over the motorway around Dublin. Some people say they are so aircraft can see lines others say so birds can see them and dont fly into them and drop onto cars.

Also usually there is 5 lines together. Is each line made up of one cooper of wire or is there multiple cores in each cable. Is it always distributed in three phase ie 3 seperate phases and a neutral or when you see two overhead cables what are those cables composed of. Are they insulated


Thanks in advance for replies.

The red balls over the M50 are for aircraft as posted. Their are also red tags but aren't that common. They are smaller than the balls and look like a very small dart board and hang from the line, usually low lying conductors to prevent birds hitting them.

As john sad about the amount of wires all correct, but that is all HV (110-400KV) The copper lines would be 10kv 3ph distribution lines with 3 conductors. Copper wouldn't be the norm as its to expensive to the stranded aluminium with a steal core is used. These would usually be 7 strands for 10kv, and would about 30 strands for HV.

The only insulated overhead conductors would be 400v or 230v. These Lv lines are the only ones with include a neutral, both single and three phase.

JOHNPT

So its just for aircraft not for birds? Surely they wouldnt prevent birds hitting wire as only placed every few hundred metres?

Davy

JOHNPT wrote: »

So its just for aircraft not for birds? Surely they wouldnt prevent birds hitting wire as only placed every few hundred metres?

The m50 are for aircraft, the ones for birds are a lot smaller and look like little dart boards or shooting targets. Look something similar to

Steve

JOHNPT wrote: »

So its just for aircraft not for birds? Surely they wouldnt prevent birds hitting wire as only placed every few hundred metres?

It's more for small aircraft as they tend to navigate visually following major roads. Some larger birds (e.g. swans) seem to follow roads as well when they migrate so it stops them hitting wires as well.

Solair

It's for small aircraft / helicopters without any doubt.