Hi

I would like to ask if anyone has any information about the Narva fluorescent tube shown in the photo below.

 I recently bought a few of these; I had assumed they were standard 40W, 120cm tubes, but it turned out to be an unusual 60cm version made by Narva. Despite having a standard "640" color rating, they are marked "not for general lighting." Unfortunately, I cannot find any technical documentation or information about them anywhere online. I even contacted the manufacturer, Narva, but was told that they stopped producing these tubes a long time ago and could not provide any information.

I suspect they might be a special version intended for laboratory use, but I am not certain.

I would appreciate any information you might have.

very cool finds! Standard Colour Modern Narva T12's are very rare, modern Day Narva only generally make special types of T12's

so they are generally only found in UV colours and the such like rather than any sort of normal shade of white, and the regular white ones you do find, will often themselves be an odd-ball rating/length, like the examples you have, but even these regular-white-but-odd-ball rating types are quite rare themselves


the examples you have are British specification 2ft 40W tubes, they run at 48V 880mA, they where introduced in 1948 designed to run 2 as a series pair off an 80W fluorescent tube/Mercury vapour choke, to make continued use of that choke type and provide a higher brightness more cold weather resistant tube for applications like street-lighting, or in applications where 5ft 80W tubes where in use and they wanted to "book end" and installation with shorter of tubes of the same brightness-per-ft-of-tube, they where quite common in England from the late 1940's-1970's but fell out favour after then as they are not the most efficient of tubes but where made for replacement purposes/special cases, into the early 2000's

(they also became common in bug zappers and the such where they are actually still made in UV form)

however the examples you have look a fair bit later than that, and I suspect where made on commission for someone looking to keep an installation of 2ft 40W lights going, Narva did/does specialise in making special types on demand if your willing to cough up the money for them to do so

they are quite cool to see it is the first time I have seen Modern Narva 2ft 40W tubes that are not UV types

very cool finds! Standard Colour Modern Narva T12's are very rare, modern Day Narva only generally make special types of T12's

so they are generally only found in UV colours and the such like rather than any sort of normal shade of white, and the regular white ones you do find, will often themselves be an odd-ball rating/length, like the examples you have, but even these regular-white-but-odd-ball rating types are quite rare themselves


the examples you have are British specification 2ft 40W tubes, they run at 48V 880mA, they where introduced in 1948 designed to run 2 as a series pair off an 80W fluorescent tube/Mercury vapour choke, to make continued use of that choke type and provide a higher brightness more cold weather resistant tube for applications like street-lighting, or in applications where 5ft 80W tubes where in use and they wanted to "book end" and installation with shorter of tubes of the same brightness-per-ft-of-tube, they where quite common in England from the late 1940's-1970's but fell out favour after then as they are not the most efficient of tubes but where made for replacement purposes/special cases, into the early 2000's

(they also became common in bug zappers and the such where they are actually still made in UV form)

however the examples you have look a fair bit later than that, and I suspect where made on commission for someone looking to keep an installation of 2ft 40W lights going, Narva did/does specialise in making special types on demand if your willing to cough up the money for them to do so

they are quite cool to see it is the first time I have seen Modern Narva 2ft 40W tubes that are not UV types

Thanks for the information, that’s a very interesting lead. Yes, my tubes are definitely quite new and almost certainly date from the 21st century. Unfortunately, I can’t figure out which date-coding system was used on them. Do you know how I could decode the date? Do you perhaps have any wiring diagrams showing how these tubes were connected, or maybe some photos or anything else related to them?

I bought the tubes from a private seller in Poland. It’s quite unusual that they were apparently made to order for a British lighting installation and somehow ended up being sold in Poland.

I’m also curious how much these tubes might be worth if I wanted to resell them.