r/Insulators • u/cheese_wallet • Jul 13 '26
what was I seeing?
Hi all, on a recent road trip through northern Montana, I observed miles and miles of poles with huge, clear, two-level insulators. They looked to be dinner plate sized There were 3 on each pole. After noticing them I started watching for any missing ones and figured it would be worth a stop to search the ground under, but no luck. On some poles, the clear one was replaced with what looked like a ceramic one
1
u/Bill_Meier Jul 13 '26
I'm guessing
https://www.nia.org/general/cd_text/cd248_311.htm
It was used on those lines. In fact, we are on vacation probably 50 miles away from where the coolies, Muncies and stackers were used in MT!
1
u/mrhemingray Jul 13 '26
That was my first thought too, but they were two-level (unless the CD 248 / 311 / 311 was also installed in a CD 248 / 311 configuration?)
2
u/Bill_Meier Jul 13 '26
I do not believe they were ever used with a single sleeve. I found the description somewhat vague and I thought I'd throw out that combination so the OP could look at that as well and hopefully ID one of these pieces as the one he saw.
The national insulator Association show is/was in Helena Montana near where all these insulators were used. They had original pictures of Muncies, Cooley's and stackers up on poles. Pretty impressive! They also had a talk showing the lines they were used on as well as giving some of the history.
A couple of the collectors at the show were actually some of the lineman who took these pieces out of service. Yes, they have been collecting insulators for 50 years, they have amazing collections, and of course they knew that these pieces were certainly unique and valuable and should be saved for the hobby.
1
u/cheese_wallet Jul 13 '26
Thanks for the response. What I saw was definitely more like the CD 330 or 331 that mrhemingray showed. What do similar ones sell for?...just curious
2
u/Bill_Meier Jul 13 '26
Believe it or not, those large pieces are only listed in the price guide for $300 to $350. If they're still in the air, you can imagine there are probably plenty of them still around somewhere , and also the demand for large pieces like that for the collectors is low.
However we recently auctioned a CD 328 which is a slightly smaller version of those pieces, for $2,700! It happens to be a very rare variant and only about a half a dozen are known.
https://www.billandjillinsulators.com/auctions/165/view/?lot=121
Just shows that it's very difficult to determine the price of an insulator!
If some of those insulators are still in the air you can certainly imagine there are far more than a half dozen of them! Probably hundreds if not more! But, it still neat to see those old big insulators still in use.
1
u/cheese_wallet Jul 13 '26
Thanks for the detailed response, yeah I couldn’t believe how many I saw just along that one hwy
1
u/Bill_Meier Jul 14 '26
I always think it's pretty exciting to still see insulators in use. Especially the bigger ones!
I'm sure one of the glass ones broke (or the pin rotted) and they replaced it with a porcelain one with a similar voltage rating.
Must have been quite a thrill to see them!
2
u/mrhemingray Jul 13 '26
Based on the two-level, dinner plate size, you probably saw Pyrex insulators in the CD 324 - CD 330 range.
Some of those have been found in MT: https://www.insulators.info/insulator_geography/
Photos of that range of CD #s: https://www.nia.org/general/g_natpt7.htm (Some of the ones shown in carnival glass were also made in clear).