ECN Forum Forums Photo Discussion Forums Photos for General Discussion Too Close for Comfort ...

In picture two: There are the two dead-end bells and then there's a jumper to... something... before it goes to the transformer. What is that? It looks like a lightning arrestor, but I don't see any ground wire.

-John

Do you mean the thing on the left side of the pole above the xfrmr? I can't remember the technical name but that is the disconect. You can't see it from this angle, but there is a place to hook on a hotstick to open it.

It's a fused cutout, usually shortened to cutout, and sometimes has been given different names like switch, but it's more than a switch. There is a lightning arrester there somewhere.

Ichabod

That's definitely too close for my liking.


A similar thing happened in the village where I was living in the early/mid 1980s. Two idiots tried to balance on the top of a ladder in a tree and lift about 20 ft. of steel mast with 18 ft. of vertical antenna down in one piece, working above their heads. The whole lot went crashing down onto 11kV lines in the adjacent field. Apparently a breaker did trip, but then went through its automatic reclose routine two or three times before locking out.

Aha, thanks for the answers. I was wondering how it could be a cut-out without a place to attach a hot-stick.

If that's an expulsion-type fuse, anyone standing at that window would get one heck of a show during an overload.

-John

Actually, there is a good possibility they'd get more than that. Expulsion cutouts open with a violent bang that could shatter that window!!

Thankfully the OP mentions that the whole set-up is being relocated.

Here at my own palatial dump, I have a 15 or 25 kva CSP pot mounted about 15 feet horizontally from my bedroom window. I guess I should be thankful that its primary is "only" 4kv.

Oh, for those who don't know, CSP means "Completely Self-Protected", in other words the fuse cutout, lightning arrestor and a secondary breaker are all internally mounted in the pot.

mxslick: I believe I have seen one of those CSP transformers around here, but they are getting rare. The one I saw had an external arrester but no cutout, although there was some form of switch handle on the side of the transformer itself, and as bizarre as it sounds, there was a red indicator light that was on all the time as well. Not sure if it had a secondary breaker either I only saw one switch handle mounted on the trans.

A.D

If someone made me guess, I'd say that would be to indicate whether the cutout had opened, otherwise there wouldn't be any visual indication.

-John

Rewired:

Oops, I did goof in my first post, for the record, any lightning arrestor will be external, not internal.


The red light is supposed to be a warning indicator, that the trans is operating on overload and the internal secondary breaker will trip at any time.

The external handle serves two purposes: It allows linemen to reset the internal breaker, and it can also be used to "temporarily" set the trip point some 150% higher. Guess how long "temporary" is and what happens next?

Big John:

Nope, the light doesn't indicate the status of the cutout, which is on the primary side. One of the reasons the linemen I have talked to hate the CSP's is because when that primary cutout opens, first there is no positive indication (other than an overall low voltage issue on the secondary lateral) and it can only be replaced in a transformer shop. So down goes the pot, and a new one goes up in its place. (Almost always a conventional style like in the pics above, with a new external cutout installed.)

Another reason the guys hate CSP's is because there have been failures that for some reason trip the secondary breaker, then when they try to reset it the pot explodes!!

Makes the job more interesting, eh? {sarcasm}

[This message has been edited by mxslick (edited 12-24-2006).]

Probably cause someone used common neutrals in the neighborhood.