Is it true that all NEMA head fixtures have latches to hold the 'bucket' (refractor module) in place instead of screws?

I believe all true NEMA heads do, however, the not so true ones may have screws to hold the reflector and refractor assembly.

I think so. Someone else feel free to correct me.

Yeah, every commercial grade NEMA head has a standard size latching for the diffuser which can be bucket style or teardrop, etc. The cheaper residential grade ones started using screw-on diffusers in the 80's I believe.

Speaking of residential NEMAs, does anyone know what the length of the short mounting arm used for wall mounting ITT/AE NEMA/security lights that didn't have cast mounting ears?

Speaking of residential NEMAs, does anyone know what the length of the short mounting arm used for wall mounting ITT/AE NEMA/security lights that didn't have cast mounting ears?

I thought I had one here at home but can't find it. I'll measure the one I have at work on Monday if someone else doesn't before then.

Thanks for the help!  The parts list from my Philips grooved head kit lists an optional 9" straight arm.  Also, the AE Deluxe Yard Lite/Big Bright kits use a short 4.5" straight arm, but I'm not sure if that is the same length as the one supplied with the NEMA style lights.

Also, anyone know what size the supplied lag bolts were?

I measure exactly 10 1/2 inches from mounted flat surface to end of the arm. Just to add, the O.D. appears to be about 1.67"....somewhere between 1 5/8' and 1 3/4' with calipers; so, weird size.

Edit...I checked another arm, it looks closer to 1 5/8" OD.

Thanks for the info!  That's longer than I thought they were.  I'd seen plenty of them, but the all my AE NEMAs that came with arms came with the 18" curved arm.

I asked my uncle who is a utility lineman in rural Minnesota,  and he said he runs in to 10" arms on the shorter ones.