Osram (UK) / GEC Date Calculator
This calculator gives up to 2 possible options of what that date might be, depending on which decade the lamp was made in- you'll have to decide which one applies most closely to the lamp in question. All this does, is remove the need for you to do the maths of which month code is which date.
This should be 2 letters, and covers lamps made since Jan 1958. However there are lamps as far back as 1945 with a letter date code and this calculator works for those too.
It assumes the letters I and O are excluded from the year sequence.
Info from an email by Colin Grimes to StreetlightingUK, May 2009.James Hooker made the following comments about this sequence however:"The pre-1958 double letter codes however, are not the same system. That was a different system for the valve factories."I've seen a couple of pre- '58 lamps though that definitely work for this sequence, so you'll have to make up your own mind!
This should be 2 letters, and covers lamps made since Jan 1958. However there are lamps as far back as 1945 with a letter date code and this calculator works for those too.
It assumes the letters I and O are excluded from the year sequence.
Info from an email by Colin Grimes to StreetlightingUK, May 2009.James Hooker made the following comments about this sequence however:"The pre-1958 double letter codes however, are not the same system. That was a different system for the valve factories."I've seen a couple of pre- '58 lamps though that definitely work for this sequence, so you'll have to make up your own mind!