I'm thinking this is more likely HPS that has lost the ignitor, since the ballast is too large to be mercury and I think I see a bit of the ignitor mount in there.

Nope. I've seen this one before the refractor door fell off. It IS Mercury Vapor.

Actually David, it looks like an HPS style....look at the coils....a MV coil would be more equal sized while the ballast here has one a lot smaller coil and a bigger coil...and it matches this one better than this one Sometimes a wrong NEMA tag or even wrong bulb is inserted and appears to be working...and sometimes it's possible they put a replacement door with blue tag....so from the ballast design..it is an HPS ballast...So I am with Niall (gailgrove) on this one! I know a lot about electricity and the components. In fact I have electric certification and looking at this, it is an HPS ballast design....

Hey Jace I just posted a comment, where did it go? And you changed yours too... Anyway, it seems his area has a lot of mislabelled lights and I am quite convinced that I see a piece of the igniter base.

Yeah because I changed mine, so it wouldn't fit what I said LOL..If I left it there, you would look like an idiot ..., after I looked at the ballast......I saw the design

And yes you are right, in some areas in Massachusetts seems to have TOTALLY neglected streetlight setup I have noticed like in Boston!

Well, this was on Truman Parkway in Hyde Park and every street light on Truman Parkway was Mercury Vapor. Now there are some Cooper OVXs that are HPS now and this was replaced by one of them.

Not only that, I found the refractor for it on the ground. So this proves it was Mercury Vapor.

Sometimes I see HPS fixtures have a MV lamp wrongly fitted in. The ballast is an HPS desgin for sure......

I thought that it was agreed upon on LG that this was HPS, and why would a MV fixture really have a plastic ignitor mount next to the ballast.

David never agreed for some reason.

I've noticed alot with Boston streetlights as well, they do alot of ballast replacements with existing fixtures, so it can be diceiving.

David......listen, sometimes ballasts are replaced but they don't change the sticker.....now this is an HPS...do not doubt the actual electricians who works with electricity. Do you have an electrical job? Some people who has commented has a job for electrical work, have experience, have electrical certificate. Do not doubt those people...unless you are an electrician or work with ballasts for a living or have a certificate.

I have a GE M-250R1 with a blue 10 NEMA tag...but the ballast itself is actually a 175 watt....so it could be a door replacement, or the sticker is wrong, or the linemen just mistakely thought it was a MV fixture and put a sticker in......

Antstar85 above, lives in Massachusetts too and works with streetlights and he knows.

BOTH websites agrees it is an HPS fixture....Everyone against you..David....you don't want to get in trouble again like you did in LG that got you kicked off for a year again

So listen to us. Thank you

Not trying to be a troublemaker, but maybe this'll clear things up. In June 2008, I found the refractor door for it on the ground. So this proves it was Mercury Vapor.

I give up.

David, the refractor door marking may have been wrong or was previous ballast......some electric companies changes the ballast.....for example there's some HPS Unistyle 400s in your area right? Well the Unistyle never came out in HPS...only MV, so the electric company changed the orginal ballast....it may be the same for this fixture, but they may have FORGOT to replace the NEMA tag.....get it? We know how to identify ballasts by looking at them...

Do YOU know how to identify by simply looking at them without any NEMA tags, labels, or even a MISSING ignitor???

David, your name is David right...if you had a name tag that said "Henry" does that prove your name is Henry? No it does not...same for the NEMA tag! Do you remember you found a NEMA tag that was yellow but had the word "MV"?? This PROVES even factory makes mistakes...so perhaps they intended to make this a MV fixture, but factory or the lineman mistakely put a HPS ballast.....this BALLAST is a HPS....but maybe it was SUPPOSED to be MV, but the ballast is an HPS period.

I've seen 100w HPS M-250R2s that have 250w HPS tags on them because the doors blew off last year.

I also know, NSTAR, Boston's electric company does not maintain they're respective streetlights. They could have some contractor with no experience sticking up a light and not checking to make sure it's a mv fixture. There could very well of been a packaging mix up at GE or somebody stuck an mv labeled door on an HPS light. I see it all the time at work. I have seen MV lamps work on a HPS ballast but the ignitor kills the lamp real quick probably the case with this fixture!

I've seen fixtures with conflicting tags before too, the nameplate on this Unidor says 400w while the NEMA tag says "20" on it.

I had a HPS PF-400 that I worked on that had a 25 sticker on IT. I relamped it twice in the Mater of two months because the lamp keep turning white and burning out. After the third time of relamping, I looked at the tag inside and the fixture was actually 400 watts. Since then the light has been problem free and that's why I now check the tag as well before relamping.

I've also seen fixtures without nema labels with the wrong lamps in them, my Westinghouse OV-15 didn't have a wattage label on the lower housing and the fixture is 250 watt MV but someone put a 175 watt MV lamp in it.