Wiring on power pole

Status
Not open for further replies.
Joined
Apr 2, 2015
Messages
1,840
Location
USA
On a power with six wires, like shown below, what line carries typically what? Also, if there is a transformer as shown, what goes in, what comes out, where does it go? Is there a ground wire in case of lightning strikes? If so, where is it and does it run down the pole. literally grounded? Enjoy my pre-school level sketch!

7f6b.jpg
 
I have seen that page. Alas, it does not really help me with assigining wjat line is what in my drawing and it doesn't show what wires go into a transformer and where they go when they come back out. You liked my drawing? Can I draw you something else? I'm doing okay with stick figures and dead body outlines.
 
Looks like two separate three phase 12.47kV feeds.
Take any two wires from one group of three, feed them into the input of the transformer. If this is a residential neighborhood, output from the transformer will be three wires (North America) to feed 240V to several houses, the two outside of the three will be your 240V, the middle one is neutral.

Commercial would be 480V three phase, I believe. I'd look for three in and three out, but a lot of commercial transformers are in fire isolation pits or rooms around here, and feeds to them are run underground with the transformer at ground level.

To add a bit, on our backyard pole I see fuses on the feed lines into the transformer on our pole.

240px-Cutout_fuse.jpg


https://en.wikipedia.org/wiki/Fuse_cutout

The two fuses go between the two wires that tap off the group of three and the input to the transformer.

Also, I don't have any training with poles and distribution lines.
 
Well I'm in So Cal. 99% of the storms here are not accompanied by lightning. I don't see static wires on residential poles here.
 
Our lines were hit by lightening a few years ago . The house light up brighter than daylight then the chain link rattled then all went black and the thunder happened. Called P.G.E and the guy came out pretty quick and explained that he would change the fuses and if that didn't fix the problem a crew would come out in the morning and change the transformer. I asked if they would install a chrome one like on the coast in Oregon and the guy said I could have any color transformer I wanted as long as it was stocked on the truck. i liked the answer.
 
Originally Posted By: BRZED
Thanks, that's very helpful. So there's no static wire?
They are grounded.
 
I have a photo of a squirrel that got too close to a transformer and some wires if anyone cares to see it.
smile.gif
 
Originally Posted By: CT8
Originally Posted By: BRZED
Thanks, that's very helpful. So there's no static wire?
They are grounded.



What does the pole ground wire connect to if there is no static wire?
 
Originally Posted By: dlundblad
I have a photo of a squirrel that got too close to a transformer and some wires if anyone cares to see it.
smile.gif



Try the food forum?
grin2.gif
 
Originally Posted By: BRZED
Originally Posted By: CT8
They are grounded.

What does the pole ground wire connect to if there is no static wire?


Tesla worked out that with polyphase, the sum of the three phases, 120 degrees out of phase was zero.

So a balanced three phase system needs no return. If it's not balanced, the imaginary "zero" floats off in the direction.

But the imbalance is often returned to ground. Some have 4 pin 3 phase, some have 3 pin.

Allows some oddball things.
* motors can operate in "star" mode, phase to neutral (nominally 240 here)
* can be operated in "Delta mode", where it's phase to phase across the windings (nominally 415 volts here)...can have switching gear that starts "star", then moves to "delta"...like changing gears on runup.
 
So the shared neutral phase is grounded at (every?) pole? Did I get that right?
 
Originally Posted By: Shannow

So a balanced three phase system needs no return. If it's not balanced, the imaginary "zero" floats off in the direction.

But the imbalance is often returned to ground. Some have 4 pin 3 phase, some have 3 pin.


Depends if it's a Wye or Delta AC configuration. Typically all three phases are never perfectly balanced, so they will use a Wye setup with a current carrying neutral that all 3 phases are tied to.

http://www.achrnews.com/articles/93448-more-delta-vs-wye-transformers

http://www.ecmag.com/section/your-business/wye-does-it-matter
 
Originally Posted By: ZeeOSix
Depends if it's a Wye or Delta AC configuration. Typically all three phases are never perfectly balanced, so they will use a Wye setup with a current carrying neutral that all 3 phases are tied to.

http://www.achrnews.com/articles/93448-more-delta-vs-wye-transformers

http://www.ecmag.com/section/your-business/wye-does-it-matter


True but there are still some (not many) single wire rural houses in my country.

Where I'm usually at, there's only three big conductors (and a massive earth grid)
 
Originally Posted By: xxch4osxx
Every pole with a transformer I see has a lightning arrestor for each phase that is grounded.


I have been looking at power poles and I always see those arrestors. How can I tell an arrestor apart from a fuse?
 
Originally Posted By: BRZED
So the shared neutral phase is grounded at (every?) pole? Did I get that right?


Yes. They run a copper wire down the pole.

That picture is two three phase circuits. The single and three phase feeders around me will always have a ground tied to the pole ground too.
 
I find power and utility poles quite fascinating. Still trying to figure out what's what.


2ic1v2s.jpg


See how the transformer is connected to the nearest line on the top of the pole? I presume at least one of the layered inline gizmos is a fuse.

qstf5x.jpg


2v9szo4.jpg

Crop: That's a lot of stuff!

huoflz.jpg

It's a modern art sculpture!

2l8vtis.jpg

Flare for the JJ Abrams fans!
 
Status
Not open for further replies.
Back
Top