When a power pole falls down

Well all the wires in my street are insulated, fortunately or I might not b e posting. However I think the power was off. The top three wires appear to be 11Kv and have large insulators and go to a transformer and then carry o n along the road, sometimes with large insulators and sometimes with small. As a temporary fix the power company connected the top three wires to the bottom three wires that my house is connected to. They've now removed the t emp connection. The bottom three wires seem to be fed from the opposite dir ection.I don't understand how several hundred houses can be fed 230 volts f rom the relatively small wires outside (which are 230 volts also of course) .

Reply to
Matty F
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But white pigments *don't* reflect it, they scatter it around in the bulk with very little loss. Look up titanium dioxide in Wikipedia. Gold foil reflects fine, or aluminium until it oxidises.

All my experience inclines me to believe the earlier poster who says carbon black filler absorbs all the damaging UV in the first few microns, although I don't personally have data to confirm this.

Reply to
newshound

Although "posh" arabs used to wear white, even before they all had limos with aircon.

Going back to the tourareg, perhaps it could be for the same reason most UV resistant plastics are black. Little radiation gets through the outermost layer, then they rely on the looseness to provide insulation and ventilation and allow perspiration to escape.

Reply to
newshound

Because (1) it shades the skin better and (2) it heats the air under it faster. As their clothing is loose, heating the air under it causes the air to rise, which creates a draught, which cools the skin.

Colin Bignell

Reply to
Nightjar

Does that imply you have whacked 'em with an ali ladder in the past or just tripping over 'em in the dark the other night?

Live cables on the ground *in general terms* will be making it fairly obvious they are still live. Even 230 V from a source capable of delivering the best part of a megawatt won't sit nice and quiet and still... Note "in general", be very wary of any downed powerlines, they could become live and leap about when a breaker trys to reset.

The 230 V from pole transformer to house is insulated here but only the phase, the neutral is uninsulated but that's not a problem as it's a combined neutral/earth connection.

I'm not sure I follow that. Presumably the lower 3 wires also go through a transformer before the power gets to your house?

That would make sense, open switches in the lines and feed from somewhere else (temporary jumpers bewteen the lines). The line that we are a spur off can be fed from either end (one end being the 33 kV substation). The other end can be fed from two different routes, one route runs along the other side of the valley, the other comes over from an adjacent valley. By opening/closeing various manual air switches a section with a fault can be isolated and the rest of the line(s) fed from other directions.

Are you sure? I suspect 11 kV distribution and transformers every so often. Quite feasable for 50 or more homes to live off one transformer, the limit is volt drop which is related to cable size and distance. I wouldn't expect 230 V to be distributed more than a couple of hundred yards. That seems to be about the distance that the density of 11 kV transformers down in the town indicates.

Reply to
Dave Liquorice

Codswallop most uv protected cable is black,probably because of cost,it is probably dearer to make colours uv safe.

Reply to
F Murtz

I think the stuff which is easiest to use to make it UV safe is carbon black. Another example is plastic plumbing - the grey stuff doesn't like light, the black stuff is ok.

Reply to
Clive George

The wiring is out in the open and very simple to follow. My house is connec ted directly to two of the lower three wires, so they must be 230v. There w as an emergency connection from the upper three wires to the lower three wi res. Therefore all of them must be 230v. All those wires have some small in sulators, i.e. 230v. Goodness knows why it's like that.

Reply to
Matty F

I think you need to revisit that conclusion. Outside plumbing is frequently grey and it is the orange pipe which is supplied for underground use.

Reply to
Roger Chapman

I suspect only where an outside tap is being plumbed with "ordinary" grey plastic pipe being used for the rest of the internal plumbing. I doubt because it is the best pipe (from a UV pov) to use.

Never seen orange water pipe but UV resistance for underground pipe is a bit of a non-issue.

Tim

Reply to
Tim+

I think Roger is talking about soil stacks

I'd call it brown rather than orange

Unless some numpty uses brown pipe intend to be buried above ground ...

Reply to
Andy Burns

Waste plumbing generally but I think I have also had grey rain water furniture in the past.

t always struck me that it was too bright to be brown when brand spanking new but technically it probably is a version of brown.

It does seem to last quite well. I have had the odd offcut lying around outside for years without it disintegrating.

Reply to
Roger Chapman

Their particular standards allocate different colours to cables based upon their voltage and or function.

Chris

Reply to
Chris J Dixon

The wiring is out in the open and very simple to follow. My house is connected directly to two of the lower three wires, so they must be 230v. There was an emergency connection from the upper three wires to the lower three wires. Therefore all of them must be 230v. All those wires have some small insulators, i.e. 230v. Goodness knows why it's like that.

You have three phases and neutral.

Reply to
harryagain

No not, its to stop the plastic decomposing in UV light seen it several times !..

We've taken down aerials that have been up for years and years and the black tie wraps are still fine. Any other colour, mainly clear ones, went ages ago!..

Reply to
tony sayer

If something looks white, then I can assure you the surface is reflective. Otherwise the surface would tend to black as reflectivity approached "0".

Reply to
Fredxx

They insulate power cables? That'll be why when you fly a kite into one you get an electric shock then..... You sure it wasn't a telephone cable?

Reply to
Gefreiter Krueger

You clearly have no idea:

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Carbon black may be used to make *some* plastics more weatherproof, others such as PVC will generally use Titanium Oxide to provide the UV screen. Yes, the cable may be coloured black as well.

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Reply to
Fredxx

You mean the way snow looks white?

Andy

Reply to
Vir Campestris

Precisely! (not sure where your explanation went though)

Reply to
newshound

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