For my installed SOI/ SOX lantern which runs daily/ nightly I like to know once again if I can use  some new acquired Philips SOX-E 36W on leak transformer which was designed for SOI 45/60/85W and of course SOX 35/55W lamps. Does the life will be much shorter with this setup? I know that the lamp current is different. 
I remember that such discussions were already held in the gallery but I cannot find it anymore.

Thanks

Depends how much different is the current, but more than about 15..20% overcurrent could be quite severe, mainly from the arctube temperature perspective. The thing is, low pressure sodium are designed with quite tight thermal budget. So you will really need to find a way to bring the current back where it should be...

Thank you Medved. I thought about the same but some lamp makers (GEC?) did allow the run of their SOX-E lamps on old leak transformer ballasts but some not so I’m not sure. I like to keep the lantern original without changing the ballast.

They did allow that for some lamps, but along with exact specification which lamp/ballast rating combinations are the allowed ones. So if your combination is one of the listed one, then you are perfectly fine.

My remark was mainly about combinations which are not along the listed ones.

I’ve now found again the description about the SOX-E lamp on James’ page: http://lamptech.co.uk/Spec%20Sheets/D%20SLP%20Philips%20SOXE26.htm

So the Philips ones should be used on SOX-E gear but as far as I understand they do work on conventional gear as well with less efficiency.