Just a little advice - Don't Touch it

I would be worried about the roofers when they put their metal safety barricades around the edge of the roof.

I can picture one of the barricades falling onto the secondary and giving a nice big spark as it shorts.

Wouldn't the primary make a bigger spark?

What on earth?

Are we actually seeing two separate buildings here with only a few inches between them, or is this one structure which has been built around the pole?

Edit: Nevermind, I've just realized what I'm looking at. At first glance I thought the paved area on the ground was actually part of another flat roof.


[This message has been edited by pauluk (edited 05-09-2006).]

Hope the HVAC guy servicing that CDU(ConDensing Unit)doesn't run a piece of copper tubing into that or *KABOOM*. :Rolleyes:

[This message has been edited by Av-guy (edited 05-10-2006).]

[This message has been edited by Av-guy (edited 05-10-2006).]

cool!

Haveing only put in large fuses in a vault what is the flashover for 13.8KV???

Wondering if those black marks on the roof are the remains of the last guy who got too close...

I see a guy wire attached to the pole. Where is the other end attached? To the building , maybe, if the separation is so minimal?

Mike (mamills)

{sarcasm on} Bet the POCO loves the easy access for re-fusing. {sarcasm off}

If I were the HVAC guy servicing this building, I would be re-fusing to go anywhere near that unit!!

Other than the obvious hazard of accidental contact, if one of those fuses should blow while you're there, there is a serious risk of flash burns, getting sprayed by melted link and needing a change of shorts!!

Look at the building in the back of the picture. Another close pole and flat roof there too.

that has to be an illusion, there would be no way to fuse those disconnects if the pole was as close to the building as it looks

Its funny u should say that mbhydro
I got a call from a roofing outfit in Philly about how they hit the elec. service. So I thought they may have hit the residential taps. When I got there they actually hit the hi-tension lines lifting a pulley to the roof. They all thought it was funny describing the flashes and arcs. I told them they are all lucky to be alive. He has a bunch of irresponsible people working for him who just worry about what time they can start hitting the bar. I told the roofer to wise up before someone gets killed and that what had happened was no laughing matter.
I went up to the roof to see the damage.The roof caught on fire,the capping shot about 1/2block away and the metal pulley was blown in two. I didn't even have to notify the POCO there were about 5-6 trucks already driving around investigating.

It is no illusion. The pole is in fact within 3 feet of the building edge. The guy is attached to a plate that is attached to the building.

Sure there is, just use a pair of channel locks.

I know of an incident where someone built right up to a power line here in Ireland. They then rang the power company to ask them to "kindly move it"..

The PoCo did accordingly and sent them a bill for £52,000 !!!

OK Bill,
Let's see that from the other side?.
It looks like it's Photo-Shopped.
I say that mainly because that rear pole brace cable seems to be going nowhere, when it should be at at least 45 degrees to the pole to counteract the line tension of 3 wires.
One other thing, that flitch plate should be attached to something.
Hummm.


[This message has been edited by Trumpy (edited 05-18-2006).]

Pair of channel locks,, I have seen channel locks and 7200v and it ain't pretty.

Trumpy - I will be back there within the next 10 days, I'll get a side photo.
Bill

That must be quite common for the POCO, because I sent in pictures just like this a year or 2 ago. The pole was right up against the building and you could just reach out and touch it.

Bill,
I think the phrase "A picture speaks a thousand words" springs to mind here.
It's amazing how a different angle can change things.
Personally I really don't see anything wrong with this distance.
Of course, if you have people near that like to stand on the edges of buildings and reach out and touch the pretty coloured fuseholders, then you may have a problem on your hands.
Thanks for the extra pic, mate.

That's true, but.......

I've been nearby (on the ground and some distance away) when one of those fuses lets go, and the resulting arc and "boom" would tend to make me not want to be on that roof servicing that A/C unit.

I guessing, based on the side view (thanks, Bill!) that being at the access door for that A/C unit puts you no more than ten feet away from and inline with those fuses.

And I don't think HVAC guys carry proper PPE for the potential (admittedly slightly possible) arc flash hazard. Or for that matter, that they are even aware that a hazard exists.

Food for thought....

edited for spelling

[This message has been edited by mxslick (edited 05-26-2006).]

Regarding those fuses:
I have heard that those expulsion fuses when they blow open, they do so with a hell of a bang and a lot of sparks and " spare parts" going everywhere... makes me not want to park under one or near one with my truck let alone be under one when it happens to " go off".. Is it true these fuses are like little bombs or firecrackers when they open? Just wondering....

The ones in my neighbourhood are the old links in the "door" type cutouts that just fizzle and open and do not make any noise from what I remember...
A.D

I have been on quite a few Projects, where similar situations existed
(pole mounted stuff, waiting to "reach out and touch someone" - in a matter of speaking... ...)

Several setups were H-Racks, but mostly they're single Poles with Pole Mounted Pots, such as in this thread's images.

With the growing trends of those beloved "Scrap-Happy Jokers"; -
of whom, I am referring to those Rocket Scientists that feel a money making career should be both; a profit situation, and an adventure;...
you know, the ones who work so hard at not working... have the philosophy "Why Work for $200.00 a day - in 8 hours, when I can risk my life, and work really hard for $100.00 a day - in 12 hours...
ones who know the Recycling Center's Staff by name...
(ok, enough about those "Ecologically Minded People"; I just love to rant!)

With the growing trends of those beloved "Scrap-Happy Jokers", wonder how long it's going to be before they try to perform "The Great Copper Harvest" on one of those Pots (Transformers)?!

I can almost see it now...

Park the Car / Truck _Right_ Underneath The Pots, go up on the roof, unbolt a Pot from the mount bracket, and it just "falls" right into the Car / Truck.

Imagine, if you will, the Vonage Commercial; where that guy decided to cut down a rather large Pine Tree, and decides to park the car right next to the tree (not so far to walk!) - and, when the tree begins falling towards the car, he tries to grab it - possibly deviating its fall...
LMAO at the Tree-Car Contact!!!

I see the same occurring with the before mentioned Scrap-Happy, Eco-Minded Personnel!

---------------------------------------
Now for something completely different.
---------------------------------------
On the Newer (?) 100 KVA White Transformer
(tagged "56, 72, 24" sounds like a quarterback ...),
I noticed the center bushing is being used.

Does this Transformer's Secondary only have a single Center-Tapped Winding, instead of having a Split-Coil Secondary?

Have seen a few 208Y/120V 3Ø 4 Wire Wye setups here and there, where the Secondary Common was connected to the Center Bushings (as in this thread's images), instead of at the left-side Bushings.

This setup appears to be a 208Y/120V 4 Wire arrangement (300 KVA, if that matters ...).
Doesn't look like a Delta, well at least the Secondary does not look "Delta-Ish"; the Primary looks really triangular to me though...

Back to the close proximity of said Pole vs/ Building:

Some time ago, I posted some images from a Project in La Jolla (the city that Bugs Bunny should have made a left turn at, after turning right at Albuquerque), where the PoCo had a Pole with 12 KV Primary Circuits "Within Reach of A 10' Stick Of EMT" for someone on the roof.

Being that the project was about 1/4 mile from the Ocean, every piece of Metal was extremely oxidized.
The Fuse Cartridges + the cutouts were a lovely green, and the Insulators had a deep buildup of dirt.

That Pole was mounted like right against the Building!

There are many "H-Racks" around here which are "Just a Hop, Skip and a Jump Away From The Roof", and for some strange coincidental reasons, the Roof Mounted HVAC Equipment is _ALWAYS_ placed right there too!
It's the oddest thing!

(BTW: "H-Rack" = certain PoCo Pole / Framing arrangement, used to set Transformers on, in-lieu of Transformers hung on Pole mounted Brackets).

Anyone know whazzup with the Common derived from the Center-Most Bushing - i.e. Single Coil Secondary???

Scott35

edited for spelling and plot-holes in story.

[This message has been edited by Scott35 (edited 05-26-2006).]

Adam,
Yes, expulsion-type fuses are designed to provide enough force upon fusing, to knock the top of the fuse link out of the holder and allow the fuse carrier to drop down and hang in it's hinge at the bottom of the fuse carrier, ready for the PoCo faultsman to replace it.
Admittedly they do go off with a rather pronounced bang, but bear in mind the amount of energy flowing through that fuse-link before it ruptures, that has to be dissipated.

I have heard that those fuses are filled with some sort of chemical which, when ignited by the melting fuse element, generates large amounts of a gas which helps to quench the arc. The "bang" they give off is a result of the rapid expansion of the gases produced.

Thank you for the information!!!
I will keep it in mind should I hear a loud bang and see one of those cutouts fallen open somewhere... ( preferably not the ones between my place and the substation

A.D

***EL~BUMPO!!!***



Scott35

BTW, anyone know if the Transformer with the White enclosure has a single secondary winding, which is "Actually" Center-Tapped?

Me...